Cirugia en El Embarazo

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Surgery in PregnancyPhysiological Changes Associated with Pregnancyand Their Impact on Perioperative Care

The pregnant woman undergoes significant physiological change that

affects almost every organ system and whose magnitude of derangement

relative to the nonpregnant state increases as the gestation progresses

(Table 1). The general surgeon must be aware of the expected changes todiscern illness from normal aberrant physiology properly, to discern

impending deterioration, and to plan operative intervention and postop-

erative care.

Fluid Hemostasis and Blood VolumeOne of the most striking changes, particularly in the later stages of

gestation, is the volume expansion that occurs during pregnancy. This

process starts as early as the 6th week of pregnancy and progresses untilthe 34th week. The expansion allows for perfusion of the placenta and

fetus and is mediated by resorption of sodium and water under the

influence of the renin-angiotension system and antidiuretic hormone.1,2

Total body water increases by approximately 3 to 4 L by the end of

gestation. Of this, 2 to 3 L comprise the placental-fetal circulation and the

remainder is due to expansion of the maternal blood volume (1500 mL).

The increase in maternal blood volume, in turn, is composed of an

increase in both plasma volume (1200 mL) and red blood cell volume(300 mL). Because plasma volume expands much more than red blood

cell volume, the hematocrit decreases, resulting in a physiologic anemia

of pregnancy.3 The hematocrit of a healthy pregnant woman is 33%.4

In addition to relative anemia, the concentration of many plasma

proteins is also decreased because of the increase in plasma volume. This

results in a net decrease in the plasma oncotic pressure, thereby predis-

posing the patient to develop interstitial edema.5 This problem is

magnified in the postoperative period because of the expected increase incapillary endothelial permeability to protein and salt. Fluid should be

Curr Probl Surg 2012;49:333-388.

0011-3840/$36.00 0doi:10.1067/j.cpsurg.2012.02.003

Curr Probl Surg, June 2012 333


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administered judiciously to maintain euvolemia while minimizing periph-

eral edema.Changes associated with blood volume have immediate ramifications to

the evaluation and care of the patient. The expanded blood volume allowsthe maternal patient to tolerate substantial blood loss with little change in

vital signs. By the third trimester, the woman can hemorrhage up to 2 L

with little change in heart rate or blood pressure.6 The placenta lacks the

ability to autoregulate flow and its perfusion is determined primarily bymaternal blood pressure. This means that hypotension will result in ashunting of blood away from the placenta-fetus and fetal hypoxia will

ensue shortly after the onset of hemorrhage or hypovolemia. Thus, the

earliest sign of impending maternal distress is fetal distress, and the fetusis critically starved for nutrients by the time that maternal hypotension

manifests.7

Cardiovascular SystemCardiac work and cardiac output increase as pregnancy progresses to

account for the metabolic demand of the fetus and also to accommodate

the fluid expansion described previously. Cardiac output can reach 140%

of normal and peaks in the second trimester.8,9 All 4 chambers of the heart

enlarge, thereby predisposing the heart to dysrhythmia, particularly atrial

TABLE 1. Key physiological changes associated with pregnancy

Cardiovascular system

X Increased cardiac output

Stroke volume heart rateX Plasma expansion

Increased propensity for atrial fibrillation

Respiratory system

X Respiratory alkalosis and increased minute ventilation

Tidal volume respiratory rate

X Decreased functional residual capacity

X Decreased total lung capacity

X Increased in systemic oxygen demand

Gastrointestinal system

X

Decreased motilityX Decreased lower esophageal tone and increased in gastroesophageal reflux

X Decreased sensitivity of the peritoneum to irritation

Hematologic system

X Anemia

X Leukocytosis

X Procoagulant state

Renal system

X Increased renal blood flow and glomerular filtration rate

334 Curr Probl Surg, June 2012


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fibrillation.10,11 At least 33% of pregnant patients will develop new-onset,clinically innocuous mitral regurgitation that will resolve postpartum.3

Cardiac output increases initially because of a rise in stroke volume andsubsequently a rise in resting heart rate.1,9,12,13 By the end of gestation, thepregnant woman will have a resting heart rate 15 to 20 beats/min greater than

baseline and a stroke volume 30% to 50% greater than baseline.

The need to maintain a high stroke volume to maintain the requisitecardiac output means that the pregnant patient is sensitive to decreases in

preload. It follows that compression of the inferior vena cava by thegravid uterus, as occurs when the patient lies supine, has significant

deleterious effects on cardiac output and, therefore, blood pressure.9 The

propensity for this to occur begins after the 20th week of pregnancy. Riskand resultant physiological derangement increase as the pregnancy

progresses such that compression of the vena cava by the gravid uteruscan result in a 30% decrease in cardiac output by the end of the third

trimester.8 The patient should always be placed in a left lateral decubitus

position with a 30-degree incline during the late second and thirdtrimester of pregnancy.

Despite the significant fluid expansion described previously, centralvenous pressure and pulmonary and systemic arterial pressures remain

unchanged.14 Progesterone acts as both a veno- and arterial dilator,

thereby keeping the central venous pressure unchanged or slightly lowerthan normal despite the increase in blood volume and keeping the

pulmonary and systemic arterial blood pressures unchanged in the face ofincreased blood volume and flow. It is never normal for the pregnant

patient to be hypertensive. An obstetrician must be consulted to evaluate

any cases of persistent hypertension with systolic blood pressure greater

than 160 mm Hg or diastolic blood pressure greater than 110 mm Hg.Furthermore, elevated venous capacitance is one reason for the signifi-

cantly increased risk of venous thromboembolic disease in pregnancy.

Respiratory SystemThe maternal respiratory system bears the burden of exchanging the

additional carbon dioxide load and providing for the increased oxygendemand generated by the placenta and fetus. Carbon dioxide exchange is

facilitated by the ease with which this molecule diffuses across thecapillary-alveolar membrane. Carbon dioxide exchange is directly pro-portional to minute ventilation, which is determined by the product of

respiratory rate and tidal volume. Minute ventilation respiratory ratetidal volume. Minute ventilation increases by 40% to 50% in pregnancywith most of the increase resulting from an increase in tidal volume.15-17



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The increased minute ventilation of pregnancy results in a physiologicalhypocapnea.18,19 The normal resting pCO2 level in a pregnant patient is

30 to 33 mm Hg. Arterial pH is kept in the normal range by acompensatory metabolic acidosis where the serum bicarbonate leveldecreases to 20 to 22 mEq/L.20-22 The need for an increased minute

ventilation coupled with a preexisting metabolic acidosis means that the

pregnant patient cannot tolerate periods of apnea, slow respiratory rate, orshallow tidal volume. This is particularly relevant during laparoscopy

because carbon dioxide diffuses between the peritoneal cavity, maternalbloodstream, and fetus until equilibrium is reached. Fetal carbon dioxide

clearance decreases and acidosis ensues at an approximate maternal pCO2level of 40 mm Hg.23 Therefore, it is imperative that either maternal

end-tidal carbon dioxide or arterial pCO2 be monitored intraoperatively

and ventilation titrated to maintain a maternal pCO2 of 28 to 32 mm Hg.Oxygen demand also increases throughout pregnancy such that it is

approximately 50% greater at the end of gestation relative to the

nonpregnant state.15,16,24 Because oxygen absorption is inefficient ascompared to carbon dioxide exchange, O2 diffusion across the alveolar-

capillary membrane is time- and pressure-dependent. As pregnancyprogresses, the gravid uterus impinges on the ability of the diaphragm to

contract and descend. This, in turn, results in a 5% decrease in total lung

capacity and 25% to 30% decrease in functional residual capacity.16,20,21

Coupled with the increased O2 demand, the decrease in functional

residual capacity renders the patient prone to hypoxia because ofatelectasis.25-27 To overcome this, the patients head should be elevated

when possible to encourage recruitment of the superior and middle

segments of the lung. Intubation should be performed by someone facile

in the procedure and, when possible, a 3- to 5-minute period ofpreoxygenation and denitrogenation of the alveoli with 100% oxygen

should be allowed.27 Maternal arterial oxygen tension should always be

at least 70 mm Hg with 95% oxygen saturation of hemoglobin to optimize

oxygen diffusion across the placenta.

Gastrointestinal SystemThe anatomic changes to the gastrointestinal (GI) system are a conse-

quence of cephalad displacement of the intraperitoneal viscera starting at12 weeks gestation when the uterus crosses the pelvic brim. Stretching ofthe peritoneum renders it somewhat less sensitive to irritation, thereby

making the abdominal examination less sensitive and reliable as an index

of underlying pathology.6,28 In addition, displacement of viscera, partic-

ularly the appendix, can result in atypical presenting signs and symptoms.



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In addition to anatomic changes, the GI tract experiences significantfunctional changes that are mediated primarily by the influence of

progesterone. These effects primarily involve smooth muscle relaxationand a relative hypotonic/hypokinetic state throughout the alimentary tract.The changes are most clinically relevant in the area of the foregut, with

diminished lower esophageal sphincter tone and impaired gastric empty-

ing. This results in a significant incidence of gastroesophageal reflux witha concomitant increased risk of aspiration. The incidence of clinically

overt gastroesophageal reflux during pregnancy is as high as 80% and the

risk for aspiration becomes significant as early as 12 to 16 weeksfollowing conception.29,30 As pregnancy progresses, gastric compression

from the late-stage gravid uterus and administration of opioids and otheranticholinergic medications can amplify these changes. Risk of aspiration

can be lowered by keeping the patients head elevated and through the useof histamine receptor-2 blocking agents or proton pump inhibitors to

decrease gastric volume and acidity.

Despite anatomic and functional changes in GI function, the incidenceof acute abdominal pathology does not change significantly during

pregnancy. The most common condition requiring abdominal operation

during pregnancy is acute appendicitis, which has an incidence of 1:1500casesthe same as the incidence in the general population.31 Progester-

one decreases gallbladder motility, resulting in a 2- to 3-fold increase inthe prevalence of gallstones in multiparous women and a 3% to 8%

incidence of neostone formation during pregnancy.32 Furthermore, theincidence of sludge in the gallbladder increases as well. However, despite

these changes, the incidence of symptomatic cholelithiasis and acute

cholecystitis does not change during pregnancy, and the prevalence of

sludge in the gallbladder is not higher than that of the general populationfollowing the birth of the child. This is most likely due to resumption of

normal biliary flow.

Hematologic SystemPregnancy has a significant impact on the hematologic system in regard

to red blood cell concentration. The increase in plasma volume relative tored blood cell mass results in a physiologic anemia of pregnancy, and

the normal hematocrit during pregnancy is approximately 33%.4 Of note,the mean corpuscular volume and mean corpuscular hemoglobin concen-tration remain within the normal ranges in the absence of concomitant

iron deficiency or other cause for hemoglobinopathy.

The anemia of pregnancy must be considered in planning an operation,particularly because most general surgical procedures performed during



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pregnancy are urgent in nature and may be associated with a higherestimated blood loss. Furthermore, a careful history must be obtained to

ensure the patient does not have other hematologic disorders, such ashereditary red blood cell disorders, that can worsen the effects of theanemia. Blood should be cross-matched for any pregnant patient under-

going operation, regardless of the magnitude of the procedure. There is no

role for preemptive transfusion to increase the hemoglobin titer inanticipation of surgical intervention, but iron supplementation may be

helpful in restoring hemoglobin levels following blood loss.

A physiological leukocytosis occurs because of increased cortisolproduction, and the normal white blood cell count can be as high as

14,000 cells/mm3. Although the increase in the serum leukocyte countdoes not affect immune function, it decreases the value of this test as a

screening tool for pathologic conditions such as appendicitis.Pregnancy is a procoagulant state. Factors VII, VIII, IX, X, XII, I

(fibrinogen), and plasminogen activator inhibitor increase significantly in

concentration and the concentration of protein S decreases.33 The normalfibrinogen level during pregnancy can be as high as 450 mg/dL, a 50%

rise relative to the nonpregnant state. Coupled with an increase in venouscapacitance and venous stasis in the lower extremities (due to compres-

sion of the vena cava by the gravid uterus), these changes result in a

5-fold increase in the incidence of venous thromboembolic disease.4,34

This risk is heightened further following operation owing to endothelial

injury, elaboration of inflammatory mediators, and immobility in thepostoperative period. Pharmacologic prophylaxis against thrombus for-

mation is mandatory, and patients should be encouraged to ambulate as

soon as possible following operation.

Renal SystemIncreased plasma volume, cardiac output, and vasodilation result in an

increase in renal blood flow and glomerular filtration rate.35 Ureteral

dilation occurs because of impaired ureteral motility under the influenceof progesterone and extrinsic compression by the gravid uterus.8 Ureteral

dilation tends to be more pronounced on the right and can increase therisk for both urolithiasis and pyelonephritis.

ConclusionsPregnant patients undergo significant physiological changes that impact

their pre-, intra-, and postoperative care. Changes related to the cardiac,

respiratory, hematologic, and GI systems can make diagnosis of acuteabdominal pathology challenging and also increase the propensity for



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perioperative complications, particularly venous thromboembolic disease.The increased metabolic demand, which manifests as increased basal

cardiac output and minute ventilation, must be accounted for intraoper-atively. When feasible, a pregnant patient should fast for 8 to 12 hoursbefore administration of a sedative to minimize the risk for aspiration.

Radiographic Imaging in PregnancyThe frequency of radiographic imaging of the pregnant patient has

increased significantly in the past decade with the greatest increaseoccurring in the use of computerized tomography (CT) scans.36 Although

this is the modality with which many surgeons are most comfortable,

other modalities that do not require ionizing radiation can also be used toevaluate the pregnant patient with a potential acute general surgical

process. Ultimately, the surgeon must be aware of the risks, benefits, anddiagnostic yield associated with each imaging modality and the impact of

the cumulative radiation dose absorbed by the mother as well as the fetus

when serial imaging studies are requested.To compare the dose of ionizing radiation associated with different

radiographic tests, one must be familiar with the basic definitions used to

describe radiation absorption and its impact on cellular function. The doseof radiation absorbed per mass of tissue is described in units of rads or,

more commonly, centigray (cGy), where 1 cGy 1 rad.37,38 It isimportant to note that a gray refers to an estimation of the dose of

radiation absorbed by the body and not necessarily the total ionizingradiation dose to which the body was exposed. For the fetus, the exact

absorbed dose is estimated based on the exposure of the uterus to the

ionizing radiation field and number of images acquired. Therefore,

estimation of the degree to which the fetus absorbs the radiation deliveredto the maternal abdomen can be very imprecise.39,40 The degree to whichtissue is damaged by the absorbed ionizing radiation differs based on its

metabolic rate, ability to repair oxidative injury, and cumulative dose of

radiation absorbed over ones life. The propensity of ionizing radiation toinjure a particular tissue bed is measured in sievert units (Sv).38 It is

generally accepted that the risk of developing cancer increases to 0.1%from an exposure of 10 millisievert (mSV).41

The potential for ionizing radiation to cause adverse effects on the fetuschanges with gestational age and is related to the dose of radiationabsorbed by the fetus.37 Exposure to as little as 0.05 mSv can result in loss

of an embryo that is less than 2 weeks in gestationan event that may not

be noticed given that most patients will not know their pregnancy statusat this time. Therefore, use of any form of ionizing radiation should be



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minimized in patients attempting to conceive. Organogenesis, whichoccurs between weeks 2 and 15, is the period at which the fetus is most

susceptible to the teratogenic effects of ionizing radiation, and maternalexposure must be minimized during this time.42 This is especially true ofCT scans, which can deliver a significant amount of radiation depending

on the test ordered and technique used. Limited use of plain radiographic

imaging is associated with very little radiation absorption (0.02-0.04mSv) and therefore is innocuous unless numerous studies are ordered.

The most common negative outcome from exposure of the fetus toionizing radiation during this time is mental retardation, but other possible

adverse events include microcephaly, ocular malformation, and cataracts.

Teratogenic effects of radiation are less common following 15 weeksgestation but the risk of pediatric malignancy increases, so the maximal

recommended dose of radiation delivered to a fetus throughout pregnancy

is 5 mSv.43 The possibility of adverse events becomes risk-prohibitive

beyond 15 mSv.37

As opposed to imaging using ionizing radiation, ultrasound and mag-netic resonance imaging (MRI) do not pose risks to the fetus. Concerns

regarding fetal acoustic damage with MRI have not been substantiated inclinical trials using a 1.5-Tesla (T) magnet.44,45 The safety of a 3-T

magnet has not been studied, and many radiologists avoid its use.46 There

are no studies evaluating the risks of gadolinium administration duringpregnancy, and the drug is classified as Category C by the US Food and

Drug Administration. Animal reproduction studies have shown an ad-verse effect on the fetus. There are no adequate and well-controlled

studies in humans, but potential benefits may warrant use of the drug in

pregnant women despite potential risks. Gadolinium does cross the

placental barrier and is excreted by the fetus in the urine, where it couldpose a risk to the fetus following subsequent ingestion in the amniotic

fluid. Generally, most MRI scans requested by a general surgeon do notrequire administration of gadolinium to address the question posed. A

radiologist should be consulted in determining whether a particularimaging request requires gadolinium.

Ultrasound in the Evaluation of the Pregnant Surgical

PatientUltrasound poses no risk to the fetus, but its diagnostic sensitivity and

accuracy are dependent on the technician performing the study, displace-

ment of the abdominal viscera, and the organ that is being imaged. It is

the test of choice when evaluating adnexal structures and can identify anectopic pregnancy in more than 90% of cases.47 However its use in



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general surgical conditions is limited, and its ability to detect pathology

decreases with increasing uterine size. The reported sensitivity of ultra-

sound to detect appendicitis in the pregnant patient varies between 66%and 100%,48-50 with many cases being nondiagnostic due to the inability

to visualize the appendix. The test is most useful in the first and early

second trimesters because the incidence of nonvisualization of the

appendix can be as high as 90% beyond the second trimester.48 Following

trauma, the sensitivity of ultrasound to detect free fluid in the abdomen

during pregnancy varies from 61% to 83%,51,52 thereby limiting its use in

this setting as well. Furthermore, the modality cannot discern the cause,

extent, or presence of ongoing hemorrhage in the abdomen. As such,formal ultrasound examination (as opposed to surgeon-directed ultra-

sound examination [FAST]) is not used routinely as a screening test in the

evaluation of the potentially injured patient. Ultrasound retains its utility

in the evaluation of gallbladder-based pathology because the sensitivity

and specificity of this test do not change in the pregnant state.

CT Scan in the Evaluation of the Pregnant Surgical

PatientThe overall use of CT scanning has increased substantially in all patient

populations, including pregnancy. The use of CT scans in pregnant

patients has increased 25% in the last 10 years.41 Recently, concern has

been raised regarding the possible association between the total dose of

radiation absorbed over a patients lifetime and subsequent cancer.53 A

head and body CT scan delivers 5 to 15 mSv of radiation, a dose that is

the equivalent of more than 100 chest radiographs.53,54 Consistent with

previous reports, 1 study of critically injured patients, as an example,found that CT scans constituted 10% of the total radiologic studies

ordered in this cohort but were responsible for 66% of the ionizing

radiation dose delivered.55

Evaluation of appendicitis is the most common reason for obtaining a

CT scan of the abdomen in the pregnant patient.41 The CT scan has very

high sensitivity (86% to 100%) and specificity (97% to 100%) for this

disease process in the pregnant state, although sensitivity decreases in the

third trimester.56-59 However, because of the need to image the pelvis,this modality is also associated with the greatest risk to the fetus.

Nonetheless, the test is indicated in cases in which the diagnosis of

appendicitis is entertained and other imaging modalities (ultrasound and

MRI) cannot resolve the issue.60 Importantly, the test should be requested

if other imaging modalities are not readily available because the risk of



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spontaneous abortion from delay to diagnosis and appendiceal perforationfar outweighs the risk of fetal malformation from exposure to radiation.

Another common reason for obtaining a torso CT scan in the pregnantpatient involves the evaluation of pulmonary embolism. The CT scan isthe test of choice in evaluating for pulmonary embolism in the pregnant

patient. This test has supplanted V/Q scanning in the general patient

population because of its proven sensitivity and specificity and speed withwhich imaging can be obtained. For the pregnant patient, studies

comparing CT scan with V/Q scan have found a lower total dose of

radiation exposure with CT scan61,62 with no change in diagnostic yield.63

Approximately 7% of pregnant patients are injured annually, and many

will require a CT scan of the abdomen and pelvis as part of their traumaevaluation. The Advanced Trauma Life Support Guidelines of the

American College Surgeons and the American College of Obstetriciansand Gynecologists explicitly state that the CT scan remains the test of

choice for imaging the abdomen and pelvis regardless of the patients

pregnancy status, and the test should be ordered as needed regardless ofpregnancy.64 However, discretion should be applied in deciding when the

risk of CT is warranted based on the patients mechanism of injury andpresenting signs/symptoms. Although ultrasound may suffice in the first

trimester, the CT scan is more useful in determining abdominal trauma in

the late second and third trimesters. The risk of CT scanning in thispopulation is related mainly to a scan of the abdomen because CT scan of

the maternal head and neck is associated with little fetal exposure to the

ionizing radiation.50 Although a CT scan of the torso delivers 11 mSv of

radiation to the mother, the fetus is exposed to a smaller energy dose.

MRI in the Evaluation of the Pregnant PatientMRI has assumed a dominant role in the evaluation of the abdomen in

the pregnant patient. As noted previously, there are no studies suggesting

a teratogenic risk to the fetus from MRI. This modality is frequently used

to determine if a patient has appendicitis. Studies suggest that MRI has asensitivity of 80% to 98% and a specificity of 94% to 100%, but, as with

CT and ultrasound, both parameters decrease and the incidence of

nonvisualization of the appendix increases with advancing gestational

age.48,56,57,65 By the third trimester, the incidence of nonvisualization canbe as high as 52%.

MRI has no role in the initial evaluation of the abdomen in the trauma

patient because of the time required to acquire images, distant location of

the MRI scanner relative to other acute care areas of the hospital, andinability to transport various types of equipment to the vicinity of the



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scanner. MRI can be used to assess the pregnant patients cervical spinebecause this study is usually not time-sensitive and can be deferred until

other critical injuries are addressed and the patients hemodynamicstability assured.

ConclusionsConcern regarding adverse fetal outcome from exposure to ionizing

radiation is greatest before 15 weeks gestation. During this period,

ultrasound and MRI may be safer and equally effective imaging tech-

niques in evaluating the pregnant patient with abdominal pain. Asgestation progresses, the sensitivity and specificity of all imaging modal-

ities decreaseparticularly for ultrasound. CT scanning may be the mostsensitive and accurate test for imaging the abdomen in the third trimester,and the risk of adverse events associated with radiation exposure is least

during this period. CT scanning remains the test of choice for imaging theabdomen and pelvis following trauma regardless of the patients preg-

nancy status. It also remains the test of choice for the evaluation of a

possible pulmonary embolism.

General Surgical Conditions in the PregnantPatient

IntroductionThe pregnant patient provides the surgeon with a unique challenge from

formulating an accurate diagnosis to providing safe treatment options.

Pregnancy does not exclude a woman from any of the surgical diseases of

the nonpregnant patient. In fact, most indications for surgery correlatewithin the age group and are independent of the pregnancy. The challenge

arises from changes in maternal anatomy from the enlarging uterus as

well as the accompanying physiological changes. These factors can causethe presentation of common diseases to be atypical and possibly delay

treatment. In addition, the surgeon must recognize how each treatmentoption affects the developing fetus. This requires close collaboration

between the surgeon, obstetrician, and anesthesiologist.

General Considerations

Every organ system is affected by the endocrinologic and anatomicchanges that occur throughout the pregnancy. Progesterone and estrogenare responsible for many of the physiological changes, while the anatomic

effects are due to the gravid uterus. The surgeon should be aware of the

normal variations that occur within each trimester involving the respira-tory, cardiovascular, renal, endocrine, and GI organs.66



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Anesthetic ConsiderationsThe risk of preterm labor from the administration of anesthesia is a

major concern for the anesthesiologist and therefore elective cases shouldgenerally be delayed until the postpartum period. However, for urgent or

emergent cases, several precautions are needed to ensure the safety of

both the patient and the fetus.67 Appropriate measures are needed to

ensure the patient does not experience hypoxia or hypotension as there are

deleterious effects that may result in fetal demise.68 The anesthetic agents

used can pass through the placenta and exert teratogenic effects.

Elective operations should be delayed until the patient has recovered

fully in the postpartum period. This allows the maternal physiology toreturn to normal and obviously eliminates any risk to the fetus. An

exception to this is a diagnosis of cancer, which may warrant intervention

if established early in the pregnancy and a long delay would be

detrimental to the patient. In this situation, and for other semielective

operations, surgery should be delayed until after the first trimester.

Surgery in the last trimester should be avoided as well to avoid the risk for

preterm delivery. The incidence of premature labor for nonobstetric opera-

tions approaches 5% and is influenced by the underlying disease process andgestational age. When an emergent procedure is necessary, the well-being of

the patient takes priority over the fetus. However, immediate consultation

with the obstetrician should be obtained to monitor the fetus, prepare for any

fetal complications, and prevent preterm labor.

Evaluation of Abdominal Pain/The Acute SurgicalAbdomen

Acute abdominal pain in pregnancy requires the surgeon to be moreastute in formulating an accurate diagnosis and treatment plan. The fact

that one must consider the risks not only to the patient but also to the fetus

can be a source of anxiety for the inexperienced. The changes of

pregnancy previously described may modify how intra-abdominal disease

processes manifest clinically. In fact, it becomes a challenge to the

physician to separate symptoms that occur routinely with pregnancy with

those of an acute abdomen requiring intervention. Because the overall

incidence of nonobstetrical intervention is very low for an acute abdomen,it can be convenient to attribute symptoms to the pregnancy rather than to

a surgical emergency.69 There is no higher risk to the patient or to the

fetus than delaying necessary intervention.70,71

The most frequent symptoms of patients who present with an acute

abdomen are abdominal pain, abdominal distension, nausea, and emesis.



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Although these symptoms are commonly seen in pregnancy, there aresubtle differences in their manifestation. Pain that is severe with a sudden

onset is suggestive of disease. Similarly, nausea and vomiting that occurwith severe constant abdominal pain and/or fever also indicate a potentialsurgical issue. Peritonitis may be present in an abdominal catastrophe.72

The accurate assessment of a pregnant patient requires knowledge of the

changing anatomical relationships of abdominal organs. The gravid uterusdisplaces the stomach further into the left upper quadrant. The small

intestine and transverse colon are also displaced upward. The ascendingand descending colon are displaced toward the flanks. Therefore, the

cecum and appendix are also displaced laterally and will continue to

move cephalad toward the liver.

Small Bowel DiseaseThe third most common etiology of nonobstetric surgical intervention is

intestinal obstruction, with an incidence of 1 per 4000 pregnancies.73 The

vast majority of obstructions are due to adhesions from prior operations,similar to the general population. Other causes of bowel obstruction with

decreasing incidence include volvulus, intussusception, hernias, andneoplasms.

The greatest risk is during the first pregnancy following abdominal

surgery. Three periods of the pregnancy are associated with a higherincidence of obstruction. The first is in the beginning of the second

trimester, when the uterus changes from solely being a pelvic organ to an

abdominal organ. The enlarging uterus will place traction on previousadhesions. The second period of risk is at the end of the third trimester

when the fetal head descends into the pelvis. The last period or risk occurs

at the time of delivery, when there is a dramatic change in theintra-abdominal anatomy.

A midgut volvulus accounts for up to 25% of small bowel obstructions,which is much higher than in the nonpregnant individual (5%). Again, the

incidence is higher in those individuals who have undergone previous

abdominal operations. This diagnosis carries with it a higher level of riskto both the mother and the fetus and prompt intervention is warranted

even if the diagnosis has not been confirmed.

The presenting symptoms of an obstruction in a pregnant patient areidentical to a nonpregnant individual and consist of the classic triad of

abdominal pain, emesis, and obstipation. The acute onset of pain ispresent in 85% of patients, but the character and nature can be highly

variable. Nausea is also a very common associated symptom, but

vomiting may only be reported in less than 25%. The fact that these 2



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complaints are typically associated with the first trimester may lead to a

delay in the diagnosis. There should be a higher level of suspicion of

obstruction if these symptoms persist later in the pregnancy. Othersymptoms include diarrhea and acute abdominal distension. The latter

may be difficult to assess with the gravid uterus. In terms of laboratory

tests, more than one half of patients will not have a leukocytosis.

Evidence of sepsis, such as fever, tachycardia, oliguria, and hypotension,

signifying that compromised bowel are associated with a higher risk of

fetal complications.

Once the diagnosis of a bowel obstruction is established, regardless of

the etiology, the treatment plan differs slightly to that in the nonpregnantpatient with the exception of the additional cautionary measures discussed

in previous sections. The surgeon should have a lower threshold for

operative intervention. Nonoperative measures should be instituted with

nasogastric decompression. However, operation should be recommended

if there is no clinical improvement during the day of presentation. The

more aggressive approach is needed because maternal mortality ranges

from 10% to 20% and fetal mortality from 25% to 50%. The incision

should be vertical to allow for optimal exposure and avoid excessivemanipulation of the uterus. The length of the incision should not be

compromised because incisions in the pregnant patient generally heal

without issue. The abdominal incision should be closed in a routine

manner.

Colon and Rectal DiseaseAcute Appendicitis. Acute appendicitis is the most common nonobstet-

ric surgical problem that requires intervention in the pregnant patient,with an incidence of 1 per 1500 pregnancies.74 The occurrence of

appendicitis can occur throughout the pregnancy but is more common in

the first 2 trimesters.75 Confirmation of the diagnosis can be a challenge

because the typical symptoms of appendicitis are present in a normal

pregnancy, including abdominal pain, nausea and vomiting, anorexia, and

leukocytosis. It is interesting to note that anorexia occurs with less

frequency compared to the nonpregnant population (60% vs 90%). The

only consistent finding is the right-sided abdominal pain, but the locationmay not be in the lower quadrant depending on the trimester.76 In most

pregnancies, regardless of trimester, the appendix can usually be found

within a few centimeters of McBurneys point.77 Peritoneal signs of

rebound tenderness and guarding are not as prevalent in the last trimester.

Most patients with appendicitis have a leukocytosis that remains in what



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is considered the normal range for pregnancy. However, the predomi-nance of neutrophils can support appendicitis.

The evaluation for acute appendicitis in pregnancy is a challenge for the

surgeon because of its prevalence and the need to establish a correctdiagnosis rapidly. Unfortunately, an infected appendix is more likely to

rupture in pregnancy most likely due to an overall delay in diagnosis.78

Ultrasound is the imaging modality of choice and offers several advan-tages. It completely avoids the use of ionizing radiation. It allows

visualization of other pelvic structures, such as the uterus and ovaries,which can eliminate other potential issues. The sensitivity and specificity

are 86% and 81%, respectively.79 If ultrasound cannot visualize thenormal appendix, the surgeon cannot rule out appendicitis. MRI, if

available, is the next imaging choice ifbeyond the first trimester because

it also avoids ionizing radiation (Fig 1).80 The sensitivity and specificity

are 100% and 93%, respectively. If MRI is not available or is inconclu-sive, then a CT scan is performed, with a sensitivity of 97% andspecificity of 100% (Fig 2).81

Appendectomy is performed for a confirmed diagnosis of appendicitis

or if it has not been unequivocally eliminated as the diagnosis. Prematurelabor is similarly frequent for both a negative exploration and an

FIG 1. MRI of the abdomen in a 35-year-old pregnant patient in her second trimester withappendicitis. The appendix is located in the right lower quadrant. The base of the appendix is dilated,measuring up to 1.5 cm. The remainder of the appendix is fluid filled with thickened walls. There is

stranding and edema in the periappendiceal tissues but no evidence of abscess or perforation.



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appendectomy, at 15%. However, fetal mortality increases substantially

from less than 5% in early appendicitis to 20% with perforated appendi-

citis.82 Thus, the treatment of suspected acute appendicitis in the pregnantpatient is emergent appendectomy. A higher negative laparotomy rate isacceptable in the pregnant population to offset some of the concerns of

the surgeon.

The technique used, open versus minimally invasive, is dependent onthe experience of the surgeon, health status of the patient, and the

trimester of the pregnancy.83 There have been arguments made for andagainst each technique; each with some validity.84-87 The open approach

avoids the use of a pneumoperitoneum and its potential effects on thefetus. It also eliminates any potential injury related to trocar placementsince there is an inherent risk of injury to the gravid uterus and fetus. In

addition, there is less effect of the pneumoperitoneum, which reduces the

working space and overall visualization with the laparoscopic ap-proach. As with the earlier trimesters, the incision should be made

FIG 2. CT scan of the abdomen in a 17-year-old pregnant patient in her second trimester withappendicitis. The appendix is located in the right lower quadrant. It is abnormally thickened and fluidfilled. There is stranding and edema in the periappendiceal tissues but no evidence of abscess orperforation.



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directly over the area of maximal tenderness, reflecting peritoneal contactof the inflamed appendix.

By contrast, there are also advantages with the minimally invasiveapproach that mimic known advantages of other laparoscopic procedures.Of interest here is the improved visualization of the entire abdominal and

pelvic contents. This allows identification of the appendix, which may

have been relocated out of the right lower quadrant as the pregnancyprogresses. The use of the minimally invasive approach comes with

special considerations. The surgeon should employ an open technique for

the placement of the first trocar rather than use the Veress needle. Thiswill eliminate the risk of an iatrogenic injury to the uterus and fetus. The

surgeon should be cognizant of the effects of the pneumoperitoneum onthe patients already compromised preload and resort to using lower

carbon dioxide maximal pressures. Minimizing pneumoperitoneum pres-

sures will prevent fetal hypercarbia and acidosis.88 The other major

advantage of the minimally invasive approach is the ability to diagnose

and intervene on other pathologies (such as acute cholecystitis) if anegative appendectomy is encountered. In the third trimester, the use of

the laparoscope is precluded, and open exploration should be thestandard.

Acute Diverticulitis. The incidence of diverticular disease in individuals

younger than 40 years of age is less than 5%, with an equal distributionamong both sexes. Furthermore, fewer than 25% of individuals with

diverticulosis will develop diverticulitis. Thus, this disease process rarely

affects pregnant individuals and is not usually part of the differentialdiagnosis for acute abdominal pain in this population. A review of the

medical literature shows a paucity of original publications other than

small case series.89

Patients will present with similar symptoms as their nonpregnant cohortand include the classic triad of lower quadrant pain, fever, and leukocy-

tosis. There may be associated symptoms, such as changes in bowel

habits and urinary symptoms. The diagnosis may be obscured in preg-nancy because peritoneal signs are not as prominent. The gravid uterus

will also make the abdominal examination difficult. This leads to a

potential delay in diagnosis and increased morbidity as a serious intra-

abdominal infection may be masked.The management of pregnant individuals mirrors that of nonpregnant

individuals; there is no level 1 evidence to suggest otherwise. CT scan

imaging remains the study of choice not only for establishing the

diagnosis of diverticulitis but its complications as well. Ultrasound alsohas reasonable sensitivity and offers an alternative. Water-soluble con-



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trast enema is another option, but will not define potential sequelae, such

as abscess. Nonoperative management includes bowel rest, IV hydration,

and IV antibiotics. If the patient responds favorably, a clear liquidfollowed by a low residual diet ensues. Intervention is required if there is

a failure of medical management and ranges from placement of a

peritoneal drain by interventional radiology for an abscess to exploratory

laparotomy for intra-abdominal sepsis. An obstetrician should be in-

volved early on in the care of the patient to provide appropriate fetal

monitoring and to assist with preterm labor.

Colorectal Cancer. The incidence of colorectal cancer is 1 per 50,000

pregnancies.90

Unfortunately, the diagnosis is often delayed because theearly symptoms of cancer mimic those of an uncomplicated pregnancy.

Abdominal distension, constipation, and anorexia are usual complaints in

pregnancy. However, a severe degree of these symptoms along with

weight loss, abdominal pain, occult fecal blood, and/or rectal bleeding

should prompt additional evaluation. This requires colonoscopy in addi-

tion to a thorough examination. Specifically for rectal cancers, most

diagnoses are made on routine rectal examinations during the pregnancy

or at the time of delivery.The management of colorectal cancer follows a similar algorithm to the

nonpregnant patient and only differs if the diagnosis is made toward the

end of the last trimester. A complete metastatic evaluation should be

made and includes the appropriate imaging studies. The carcinoembry-

onic antigen (CEA) level is of little utility during pregnancy. Any

resectable lesion without the presence of metastatic disease should be

resected following oncological principles. The only exception that allows

a delay in intervention is if the expected delivery date is forthcoming. Inthe situation where metastatic disease is documented, surgery should be

delayed until after delivery and is based on a discussion with the patient.

The choice of incision is based on the location of the cancer and the

stage of the pregnancy to ensure optimal exposure and a formal

oncological resection. If the decision has been made to treat the cancer

after delivery, then the risks of a vaginal delivery versus a Caesarean

section are considered. In most cases, the type of delivery is dictated by

the obstetrical indications. However, a Caesarean section is indicated forlarge lesions located in the pelvic cavity. Any adjuvant therapy should be

delayed until after delivery. Although neoadjuvant chemoradiation is the

standard treatment for rectal cancer in the nonpregnant patient, it is

avoided in pregnancy. Ultimately, pregnancy does not affect the long-

term maternal outcome in colorectal cancer.



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Hemorrhoids. Hemorrhoids are the most common anorectal disease inpregnancy. Fortunately, the symptoms are usually mild and transient,

consisting of discomfort and minor bleeding. Treatment before delivery isdirected toward relief of the symptoms with nonprescription medicationsand sitz baths. Regulation of diet by increasing fiber and other bulking

agents helps to minimize constipation and straining. Any surgical

intervention should be delayed until the postpartum period if the hemor-rhoids remain a persistent issue. The only exception would be Grade 4

internal hemorrhoids with incarceration, thrombosed external hemor-

rhoids, or persistent significant bleeding.91 In the evaluation, the surgeon

should always be mindful of the possibility of an underlying malignancy,

which may warrant a proctosigmoidoscopy or colonoscopy.

Other Colonic Disease. Sigmoid volvulus is a potential etiology of a

large bowel obstruction. If possible, this condition should be managednonoperatively unless bowel ischemia is a concern. Colonoscopic decom-

pression along with a rectal tube is effective. As with the nonpregnant

population, recurrence is generally the rule and so definitive interventionis planned after the delivery.

As opposed to a mechanical obstruction, colonic pseudo-obstruction is

a functional process resulting in an ileus. Although the vast majority ofOgilvies syndrome is seen in the elderly population or non-obstetric-

related surgeries, approximately 10% of cases occur in the postpartumperiod. Again, nonoperative management is usually effective, with

colonoscopic decompression for severe cases, reserving exploration for

suspected bowel ischemia or perforation.

Hepatobiliary Disease

Gallbladder Disease. The second most common nonobstetric surgicalprocedure performed in pregnancy is cholecystectomy. As with thenonpregnant population, there is only a small percentage of patients who

are symptomatic from the presence of cholelithiasis, although there is a

higher incidence of cholelithiasis in pregnancy.92 The symptoms ofbiliary colic are similar in either cohort. It is important to note that

jaundice in a pregnant patient has different etiologies and prevalence.

Hepatitis accounts for 45% of cases; benign cholestasis accounts for 20%,

and choledocholithiasis accounts for only 7% of cases. In contrast toappendicitis, there is virtually no diagnostic dilemma because ultrasoundremains as accurate an imaging study.

There have been several studies, both retrospective and prospective, that

have examined medical versus surgical management of symptomaticbiliary tract disease in pregnancy.93 Conservative management is advo-



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cated for asymptomatic cholelithiasis. The results of these studiesconclude that surgical intervention should not be reserved for the sequelae

of cholelithiasis, such as cholecystitis, choledocholithiasis, and gallstonepancreatitis. Although there are complications of surgery that can result inboth maternal and fetal morbidity, there is similar morbidity from

nonoperative management. Furthermore, nonoperative management leads

to increased length of hospital stay, multiple readmissions, and higherincidence of preterm deliveries.

In a study from the University of Pittsburgh Medical Center, which

included 58 patients, 9 of the 39 patients in the medical observation grouphad multiple hospital admissions.94 Laparoscopic cholecystectomies were

performed safely in all trimesters, with only 1 complication leading to acystic duct stump leak. The results are similar to the University of

California at San Francisco study that showed a 38% relapse rate in thenonoperative group.95 The rate is trimester-dependent: 55% in the first 2

trimesters and 40% in the last trimester. The rate of fetal demise is 2.2%

from surgical intervention and 7% with nonoperative management.These studies support the notion that pregnancy should not be consid-

ered a contraindication to cholecystectomy. Complications from nonop-erative management are higher than uncomplicated surgical intervention.

However, the timing of the surgery is trimester-dependent. The sponta-

neous abortion rate was reported to be 12% in the first trimester comparedto 0% in the second and third semesters. The risk for preterm labor is 0%

in the second trimester compared to 40% in the third trimester.95 Thissuggests that the second trimester is the optimum period in which to

intervene.

Laparoscopic cholecystectomy can be performed during each of the

trimesters.96 The limitation to this approach is surgeon experience andavailable resources to address preterm labor, which is highest in the lasttrimester.97 An open technique is advocated for peritoneal access to

prevent iatrogenic uterine injury. If intraoperative cholangiogram is

performed, the fetus must be properly shielded from fluoroscopy. Pretermlabor can be managed successfully with tocolytics, but is not routinely

indicated.

Acute Pancreatitis. Acute pancreatitis occurs infrequently in pregnancy

with an incidence of 3 per 10,000 pregnancies.98 Overall, pancreatitisfrom a biliary etiology has better outcomes. Gallstone pancreatitis can bemanaged successfully with the same modalities, including endoscopic

retrograde cholangiopancreatography with sphincterotomy.99 An onlinereview of the medical literature produced 12 reports of gallstone pancre-

atitis in which there was 8% fetal mortality in the conservative group and



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2.6% in the surgery group.100 Although not statistically significant, this

suggested earlier surgical intervention for this disease process. Pancreatic

pseudocyst is a potential sequelae of pancreatitis, with associated mater-nal and fetal morbidity rates approaching 20%. Percutaneous drainage

with endoscopic retrograde cholangiopancreatography and sphincterot-

omy is an ideal option before delivery followed by definitive surgical

treatment in the postpartum period if necessary.

Hepatic Adenoma. Hepatic adenomas are uncommon benign epithelial

tumors predominately found in young women and are associated with oral

contraceptive use.101 They are usually solitary lesions in the right hepatic

lobe. Although considered benign, there is a low rate of malignanttransformation. There is a particular association with pregnancy with the

concurrent increase in endogenous steroid hormone levels. The major risk

in pregnancy is hemorrhagic shock from spontaneous rupture of the

tumor. The mortality for both the patient and the fetus approaches 60%.

Thus, prompt diagnosis and treatment are crucial.

Clinically, the patient may present with right upper quadrant or

epigastric pain. An abdominal mass may be palpated for larger lesions.

Jaundice may arise from the compressive effects of the tumor. Hypoten-sion is an ominous sign and signifies rupture. The alpha fetaprotein should

not be elevated unless malignant transformation has already occurred.

Imaging studies include ultrasound, MRI, and CT scan.102 Percutaneous

biopsy is avoided as part of the diagnostic evaluation because of the risk

of postprocedure hemorrhage.

The high mortality rate associated with rupture during pregnancy

necessitates elective resection of a hepatic adenoma. Again, the ideal time

is during the second trimester to minimize the operative risks. A rupturedadenoma should be treated emergently with laparotomy to control the

hemorrhage and resect the lesion. A concomitant Caesarean section may

be indicated dependent on the gestation age.

HELLP Syndrome. HELLP syndrome refers to a severe form of

pre-eclampsia involving Hemolysis, Elevated Liver enzymes, and Low

Platelet count. It occurs infrequently with an incidence of 2 per 1000

pregnancies. It typically manifests in the third trimester to the early

postpartum period. The patient presents with abdominal pain, nausea,emesis, and malaise. Hypertension, jaundice, and ascites are other major

findings. The diagnosis is established with appropriate laboratory tests.

Morbidities associated with HELLP syndrome include disseminated

intravascular coagulation (DIC), placental abruption, acute renal failure,

pulmonary edema, and hepatic infarction, hematoma, or rupture. The



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hepatic complications can be evaluated with CT or MRI (Figs 3 and 4).A marked elevation in serum aminotransferases and fever is also noted.

The mainstay of treatment is delivery after resuscitation, if possible.103

The specific management of hepatic hematoma is dependent on the

hemodynamic stability of the patient. If the patient is stable and the

hematoma is contained and stable, then nonoperative management isappropriate with serial imaging. The lesion will resolve over a course of

several months. Operative intervention is indicated for hemodynamic

instability, ongoing bleeding, and increasing size of the hematoma onserial imaging. Maternal and fetal mortality rates are 60% and 85%,

respectively, in this situation.104 Surgical options include packing, hepaticartery ligation, and/or resection.

Inflammatory Bowel DiseaseThere are several studies that have noted an increase in adverse

obstetrical outcomes with inflammatory bowel disease.105,106 The effect

of ulcerative colitis or Crohns disease on the pregnancy is mostlydependent on the severity of the disease at the time of conception. It isimportant for the surgeon to understand how management of this disease

differs in pregnancy, in terms of both medical and surgical intervention.

Ulcerative Colitis. Fortunately, patients who are in remission at the timeof conception are likely to remain so during the duration of the pregnancy.

FIG 3. Ultrasound imaging of a 37-year-old patient with hepatic rupture associated with HELLP syndrome.There is subcapsular echogenic material consistent with hematoma measuring up to 1.4 cm.



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Relapse occurs at a similar rate as in a nonpregnant individual, or

approximately one third of patients. The first trimester is the most

common period for relapse, which allows remission to be achieved before

expected delivery. For those patients who have active disease, pregnancyshould be delayed until remission is achieved because the disease mayworsen in pregnancy, making remission difficult to achieve. The overall

rate of complications is not different than for nonpregnant individuals. If

surgery is required, premature labor or spontaneous abortion may occur.Severe relapses during pregnancy requiring hospitalizations are another

risk factor for preterm delivery and low birth weights. After delivery, the

disease continues a similar course as before conception.

Crohns Disease. As with patients with ulcerative colitis, the diseasefollows a similar pattern and the pregnancy itself does not alter the courseof the disease. The complications from the disease are also similar to that

seen in the nonpregnant individual. The one exception is the development

of an entero-uterine fistula documented in case reports.107 Women with

Crohns disease are at an increased risk for premature delivery and low

FIG 4. CT scan of the abdomen in a 37-year-old patient with hepatic rupture associated with HELLPsyndrome. There is a region of decreased density along the hepatic dome reflecting devascularizedliver parenchyma and perihepatic hemorrhage. Free intraperitoneal fluid is present.



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birth weights.105 These adverse outcomes are more frequent if pregnancyoccurs while there is active disease or if remission is not achieved during

the pregnancy. Contrary to ulcerative colitis, another consideration is theextent of perianal involvement. A Caesarean section may be warrantedoutside of obstetrical indications if there is active disease and the potential

of an episiotomy exists. This may create a situation in which an iatrogenic

perineal fistula may develop.

Medications. A detailed discussion of each class of medications used to

treat inflammatory bowel disease is beyond the scope of this article. In

brief, most medications used to treat the disease in nonpregnancy can alsobe continued during the pregnancy. The reader is advised to refer to the

manufacturers prescribing information for specific details. The use ofmethotrexate is absolutely contraindicated in pregnancy because of its

association with spontaneous abortion and fetal skeletal abnormalities.

Antidiarrheal medication containing dephenoxylate and atropine shouldalso be discontinued during the first trimester because fetal malformations

are reported with their use.

Surgery. If inflammatory bowel disease is refractory to medical therapyduring pregnancy, surgery may be necessary. A proctocolectomy with end

ileostomy may be needed for the development of fulminant colitis.108

Surgery is associated with spontaneous abortion or premature labor and the ideal

period for intervention to avoid these specific complications is the secondtrimester. The surgeon must be aware that there may be subsequent issues with

the stoma as the patient continues to gain weight, with stoma retraction, prolapse,and parastomal hernia. A stoma nurse should be available to help with any

appliance issues as the contour of the abdominal wall changes.

For those individuals who have had ileoanal pouch reconstruction, there

will be minimal effect on function with the possibility of increased stoolfrequency. A normal delivery should be expected with either a Caesarean

section or a vaginal delivery.109 During a Caesarean section, a general

surgeon should be available in case adhesions are encountered between

the uterus and the anterior wall of the pouch to prevent perforation.110

Thyroid DiseaseThere is appreciable morbidity associated with thyroid dysfunction in

pregnancy, leading to adverse obstetrical outcomes.111 The treatment ofthyroid disease is dependent on whether it is a hormonal dysfunctioncausing hypo- or hyperthyroidism or a malignancy is suspected with the

presence of a nodule. Although the treatment regimen parallels that of the

nonpregnant individual, management of thyroid disease in pregnancymerits additional considerations because of the physiological changes in



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thyroid function.112 Currently, universal screening of pregnant women isnot supported despite the potential of adverse effects for the pregnancy

and fetus. Thus, thyroid testing during pregnancy is reserved on symp-tomatic women or those with a prior history of thyroid disease.

Hypothyroidism. Clinical hypothyroidism is unusual in a healthy

pregnancy because of the associated increased risk of spontaneous

abortion in the first trimester. Although the incidence of hypothyroidismoccurs in 2.5% of pregnancies, only a minority will develop symptoms.

However, if the condition persists through the latter stages of pregnancy,

it can be associated with a myriad of complications, including pre-eclampsia, placental abruption, preterm delivery, perinatal morbidity and

mortality, and postpartum hemorrhage. The diagnosis is established by anelevated thyroid stimulating hormone (TSH) and a low free T4 level. The

goal of therapy is to normalize serum TSH levels with thyroid hormone

replacement with levothyroxine.113 TSH levels should be measured every

4 weeks with any change in replacement dose and at least every trimester.

Hyperthyroidism. Clinical hyperthyroidism complicates 2 per 1000pregnancies and is second only to diabetes mellitus as the most common

endocrinopathy in pregnancy. The differential etiologies include hydatid-iform mole, hyperemesis gravidarum, multiple gestations, and Graves

disease. The latter is the most common cause of hyperthyroidism.

Because the clinical features of hyperthyroidism can be similar to those ofan uncomplicated pregnancy, the diagnosis is established with laboratory

tests with a low TSH and elevated free T4 level. Maternal morbidity

includes premature delivery, placental abruption, pre-eclampsia, conges-tive heart failure, and thyroid crisis.114

The presence of a goiter, exophthalmos, and weight loss support the

diagnosis of Graves disease. Antithyroid drugs are the treatment ofchoice in pregnancy. Propylthiouracil (PTU) and methimazole (MMI) arethe drugs used and have differing toxicities. Although PTU is associated

with hepatotoxicity, it is preferred in the first trimester because MMI has

teratogenic effects. Later, to limit this adverse effect of PTU, therecommendation is to switch to MMI in the second trimester. The goal of

treatment with thioamide drugs is to maintain free T4 levels in the upper

normal range and TSH in the low normal range using the lowest possible

dosage. This requires thyroid function tests to be evaluated monthly.Radioactive iodine is an absolute contraindication, with an association ofthyroid cancer in the offspring. In most patients, symptoms improve with

a return to normal thyroid levels 1 to 2 months after initiation of therapy.

Thyroidectomy may be indicated if the first line of medical treatment isnot successful. Indications include intolerance to thioamides, requirement



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of high dosages, development of agranulocytosis, noncompliance, orcompressive effects from a large goiter. Surgery is avoided until the

second trimester to avoid preterm delivery or spontaneous abortion.Although iodine is avoided because of adverse affects on the fetus, it isused to prepare the patient for surgery to minimize perioperative

complications. It is important to note that Graves disease is characterized

by a recurrence in the year following delivery. Last, when treatinghyperthyroidism in pregnancy, appropriate fetal monitoring is necessary

to evaluate for thyrotoxicosis with fetal heart rate and fetal growth.

Thyroid Nodules and Goiter. Goiter during pregnancy is uncommon inthe USA and is found in regions where iodine intake is low. Physiolog-

ically, plasma iodide concentrations decrease in pregnancy because ofincreased maternal renal clearance and fetal uptake. This relative defi-

ciency may lead to mild thyroid enlargement, which is palpable on

examination. Any significant growth should be considered abnormal andwarrants further investigation.

Any thyroid nodule found in pregnancy is managed the same as in the

nonpregnant patient.115 This includes fine needle aspiration and ultra-

sound. Thyroid radionuclide scanning is not recommended. If pathologyis benign, then appropriate follow-up is warranted. Any nodule that

enlarges warrants a repeat biopsy. If cytology confirms thyroid cancer,

surgery is recommended. Given that thyroid cancer is typically indolent,thyroidectomy is typically delayed until the postpartum period. This

approach is safe and studies have shown no difference in the outcome of

recurrence or metastatic disease when compared to surgery performedduring the pregnancy.116 In addition, complication rates are higher if

thyroidectomy is performed during pregnancy and include higher rates of

hypoparathyroidism, hypocalcemia, and recurrent laryngeal nerve in-jury.117 In the last scenario in which the biopsy is indeterminate, it isappropriate to follow the patient and delay further testing (eg, thyroid

scan) until the postpartum period.

Adrenal TumorsThe incidence of adrenal tumors is not increased in pregnancy.

However, the diagnosis of a functional tumor can be complicated because

pregnancy does upregulate several hormonal pathways. In addition,several symptoms of a functional tumor are similar to normal complaintsof a pregnancy or its common complications, such as gestational diabetes.

The evaluation for an incidental adrenal adenoma is similar to that of a

nonpregnant individual with the exception of certain imaging studies.Where nonfunctional tumors should be followed with repeat imaging in



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the postpartum period, adrenalectomy is warranted if biochemical mark-ers support a functional tumor.

Hyperaldosteronism. Primary hyperaldosteronism is very uncommon,but has catastrophic results in pregnancy. Its diagnosis is complicatedduring pregnancy. There is a physiological rise in aldosterone because all

components of the renin-angiotensin-aldosterone system are upregulated.

A corresponding suppressed renin level confirms the diagnosis.118 The

accompanying hypertension and hypokalemia may become more difficult

to control as the pregnancy progresses, which can lead to placentalabruption, preterm delivery, and intrauterine growth retardation.

However, if imaging studies do not define an adrenal lesion, then

medical management is employed until delivery. Spironolactone iscontraindicated with its association of ambiguous genitalia. Surgical

intervention may also be delayed if hypertension can be controlled

adequately early in the pregnancy. Otherwise, with unilateral adrenaldisease, an adrenalectomy should be performed.

Cushings Syndrome. As with other functional adrenal tumors, theoccurrence of Cushings syndrome is also a rare event during pregnancy.

Adrenocorticotrophic hormone-independent adrenal tumors are more

common than pituitary tumors in the pregnant patient. The diagnosis of afunctional adrenal lesion may be obscured because there is an upregula-

tion of the hypothalamic-pituitary-adrenal axis producing physiological

hypercortisolemia of pregnancy.119 Confirmatory biochemical markers

include an elevated serum cortisol level, elevated 24-hour urinary cortisollevel, and suppressed adrenocorticotrophic hormone level. Noncontrast

MRI is the imaging study of choice. The symptoms of the disease include

weight gain, hypertension, hyperglycemia, fatigue, and emotional changes,

which are many of the same changes noted in a normal pregnancy. Cushingssyndrome should not be confused with pre-eclampsia or gestational diabetes.

Cushings syndrome is associated with severe maternal and fetalcomplications and so an early diagnosis is critical. Adrenalectomy is the

treatment of choice unless delivery is imminent. There is a limited role formedical management since most of the drugs available for use in the

nonpregnant individual are contraindicated secondary to teratogenic

effects.

Pheochromocytoma. Pheochromocytomas are also uncommon in preg-nancy, but must be included in the differential diagnosis for hypertension.

Adrenal lesions that remain undiagnosed in pregnancy are associated withsignificant maternal and fetal mortality. Unlike the previously discussed

functional tumors, pheochromocytomas exert their greatest risk at theonset of labor to the early postpartum period. With appropriate treatment,



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maternal mortality can be limited.120 The diagnosis is confirmed with theappropriate biochemical markers, including 24-hour urine catecholamines

and metanephrines. Metaiodobenzylguandine scan is not recommended inthe pregnant patient.The primary goal in the management of pheochromocytoma in preg-

nancy is the avoidance of a hypertensive crisis until surgical intervention.

Adrenalectomy should be performed in the second trimester to avoidspontaneous abortion. The preparation of the patient involves alpha

followed by beta blockade. Although phenoxybenzamine can be used for

alpha blockade, its long-term effects on the fetus are unknown. Calciumchannel blockers are known to be safe in pregnancy. Beta blockers are

associated with intrauterine growth retardation and so close fetal moni-toring is required with their use. If the diagnosis is not made until the last

trimester, delay of the adrenalectomy is an option until the postpartum

period. Caesarean section is the preferred mode of delivery in this case toallow the anesthesiologist to have more control over the hemodynamics

of the patient.

HerniasPregnancy is a risk factor for the development of a symptomatic

umbilical or inguinal hernia as the gravid uterus becomes larger as the

pregnancy progresses. Pre-existing hernias may become symptomatic.The enlarging uterus may actually help prevent bowel incarceration in

inguinal hernias by displacing the bowel upward. Unless there is thepresence of an incarcerated hernia, elective repair should be avoided until

the postpartum period as there is minimal risk of hernia-related compli-

cations. Bowel obstructions are discussed in a previous section. A

retrospective study of 12 pregnant patients noted that it was safe to delaysurgery until after delivery.121 No patient developed an incarceration orstrangulation during the pregnancy necessitating an emergent repair.

Elective repair was performed an average of 22 weeks postpartum

without complication.

Vascular DiseaseAcute Venous Thromboembolism. Acute venous thromboembolism

(VTE) is 4 to 6 times more common in the pregnant patient compared tothe general population, with an overall incidence of 2 per 1000 births.122

There are several etiologies for the transient hypercoagulable state. A

normal pregnancy is accompanied by an increase in clotting factors and

a decrease in anticoagulant activity. The latter is related to a decrease inprotein S levels. Other factors include venous compression by the gravid



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uterus, decreased activity level, and potential vascular injury from aCaesarean section. The risk is slightly higher in the third trimester and in

the postpartum period. A retrospective review noted an incidence of0.22% over a 6-year period examining 33,311 deliveries.123 A majority ofthe postpartum VTE was associated with Caesarean sections and there

was an association with oral contraception and hormonal stimulation. A

history of a VTE increases the incidence of a recurrence to 12%.124

The initial symptoms from VTE are shortness of breath and lower

extremity swelling and pain. There may be a delay in the diagnosisbecause, to some extent, these complaints are common in an uncompli-

cated pregnancy. The physician must have a high index of suspicion to

investigate further with ultrasound and/or CT scan.125

Fortunately, despite the physiological and mechanical factors related to

VTE, pregnancy alone is not an indication for anticoagulation. If anticoag-ulation is required, options are limited to either unfractionated or low-

molecular-weight heparin. Unlike heparin products, warfarin is contraindi-

cated because of its known teratogenic effects. For those individuals who dorequire anticoagulation for any reason, the current recommendation is to

continue the regimen for the first 6 weeks postpartum.

There is a role for the placement of temporary inferior vena cava filtersfor the prevention of pulmonary embolism in pregnancy. A small

retrospective review was conducted of 11 patients with a deep veinthrombosis for the prevention of pulmonary embolism in pregnancy who

underwent placement of an inferior vena cava filter.126 All the filters wereplaced before delivery without complication. No pulmonary embolism

occurred, which allowed the removal of all filters. One filter was

exchanged for a permanent filter with the presence of a large thrombus

within the filter.The management of VTE in pregnancy parallels that for any patient with

the exception of the use of warfarin. Recommendations for the surgeon in thetreatment of a VTE in the perioperative period are based on literature not

primarily focused on pregnancy. In fact, a recent review of the CochraneDatabase noted that there are no randomized clinical trials examining the

effectiveness of anticoagulation for VTE in pregnancy.127

Splenic Artery Aneurysm. Splenic artery aneurysms are the third most

common intra-abdominal aneurysm, with an incidence of 10%.128,129 It isa particular concern in pregnancy and in women of childbearing agebecause of the higher rate of rupture and morbidity. Multiparity is a risk

factor. The increased portal blood flow and hormonal influences on the

arterial wall are contributing factors. Aneurysms are usually asymptom-atic until they rupture. Fortunately, up to 25% of patients will present with



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an initial contained rupture, which carries a much more favorable

outcome. The risk of full rupture in pregnancy ranges from 20% to 50%

and is considered a catastrophic event, with maternal and fetal rates of75% and 95%, respectively.130 The third trimester is the most common

time for rupture, but there are case reports of aneurysm rupture in the first

trimester as well.

When treated electively, the mortality rate is less than 1%. Thus, when

the diagnosis is made in a woman of childbearing age or in pregnancy,

patients with aneurysms 2 cm or larger should undergo intervention.

Options for intervention include coil embolization, stent placement,

arterial resection with reconstruction, and splenectomy.

131

TraumaTrauma injury occurs in the pregnant patient, with an incidence of

approximately 5%, ranges from being insignificant to having a cata-

strophic result with loss of maternal and/or fetal life.132,133 In fact, trauma

is responsible for a significant cause of nonobstetric mortality in the USA.

Blunt trauma is more frequent and the mechanism of injury usually

involves motor vehicle accidents.134

In a retrospective review by Shah of114 patients, 70% of trauma was attributed to automobile accidents, with

domestic violence following at 12%.

There have been several retrospective studies that have attempted to

identify predictors of fetal demise. The Injury Severity Score is 1 measure

that has been analyzed and higher scores are associated with fetal demise.

Other predictors are severe abdominal injury, maternal shock, placental

abruption, DIC, and maternal mortality. Another study concluded that in

addition to severe abdominal injury, severe head, thoracic, or lowerextremity injury also present higher risks for pregnancy loss.135

The initial evaluation of an injured pregnant patient is identical to that

of the nonpregnant patient using the Advanced Trauma Life Support

protocol. Any intervention that is required to save the mothers life should

be performed even if it poses a potential risk to the fetus. However, there

are several important considerations the surgeon must keep in mind

during the primary survey. There are physiological differences in preg-

nancy that may complicate the initial evaluation. The pregnant patient isable to tolerate acute blood loss better because of the increase blood volume.

Clinical signs of shock, such as tachycardia and hypotension, may be delayed

until there is a 30% reduction in blood volume. Also, the mother attempts to

be normotensive by decreasing perfusion to the uterine vascular bed.

Although the mother may not exhibit hypotension, the fetus may be



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experiencing anoxia. Early aggressive resuscitation should be initiated

even in the normotensive patient.

After the initial evaluation is underway, imaging studies and

diagnostic studies are ordered in accordance with standard traumaguidelines. The fetus should be spared unnecessary radiation exposureand can be protected by proper shielding.136 Ultrasound is advanta-

geous in this regard and should be employed liberally. With blunt

trauma, the spleen is the most commonly injured organ. The graviduterus is also a concern with blunt trauma after the first trimester since

it no longer a pelvic organ. Intrauterine hemorrhage and rupture can bedetected on examination if there is a discrepancy in gestation age and

measurement of uterine fundal height (Fig 5). A pelvic examination is anessential component to detect vaginal bleeding, which would indicateplacental abruption or preterm labor. Again, the previous condition is the

leading cause of fetal loss after trauma. Fetal monitoring detecting deceler-

ations also indicates preterm labor. The presence of amniotic fluid mandatesemergent Caesarean section.

FIG 5. CT scan of the abdomen in a 47-year-old patient with uterine rupture. There is an extensiveamount of gas and fluid in the endometrial cavity extending through the uterine wall anteriorly on theleft side. A small amount of fluid and gas is seen in the intraperitoneal cavity.



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Penetrating trauma is associated with more ominous outcomes. The

morbidity from penetrating wounds is a reflection of the number of organs

involved. With increasing gestation, the uterus will shield other visceraand allow the bowel to escape injury. Gunshots to the abdomen result in

70% perinatal mortality because of direct injury to the fetus and

premature delivery.

Although a full discussion of orthopedic injuries is beyond the scope of

this section, particular consideration is given to pelvic fractures. A recent

publication suggests that a pregnant patient with an orthopedic fracture

should be regarded as a high-risk obstetrical patient.137 There is a

significant increase in pelvic venous capacity, which may result insignificant retroperitoneal hemorrhage with a pelvic injury. The observa-

tional study included 965 pregnant individuals with and without ortho-

pedic trauma. Patients with orthopedic trauma had a higher risk of

preterm delivery (31% vs 3%), higher risk of placental abruption (8% vs

1%), and higher risk of fetal mortality (8% vs 1%).

Motor vehicle accidents are the leading cause of maternal and fetal

injury during pregnancy. A study from Virginia Commonwealth

University Medical Center noted that one half of the trauma evalua-tions in pregnant patients were associated with such accidents.138

Unfortunately, 34% of theses individuals were unrestrained. Pelvic

fractures were identified as an independent risk factor for fetal

mortality (4.7%). A literature review of pelvic trauma was conducted

and demonstrated a 9% maternal mortality rate and a much higher fetal

mortality rate of 35%.139 The type (pelvic, acetabular), classification

(simple, complex), or trimester at time of trauma were not independent

risk factors. However, the mechanism and severity of injury diddictate morbidity rate.

There are 2 other issues confronting the trauma surgeon during the

initial evaluation. The first is the role and timing of a Caesarean

section to save the fetus from demise. A Caesarean section may be

indicated dependent on the gestational age. Consultation should be sought

with an obstetrician and neonatologist to discuss the viability of the

pregnancy. Once a viable pregnancy is confirmed, indications for Caesarean

section include: if the mother has suffered severe trauma and is nonrespon-sive to resuscitation efforts, if there is imminent maternal demise, and/or if a

non-reassuring fetal heart rate is detected on the fetal monitor.

In the setting of blunt trauma, fetal-maternal hemorrhage may occur.

The administration of anti-D immunoglobulin is recommended for

Rh(D)-negative patients to prevent Rh(D) alloimmunization.140



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Breast Disease in the Pregnant PatientThe extensive physiological changes that occur in the breasts during

pregnancy and lactation often make detection and management of breastlesions difficult for the surgeon, radiologist, and pathologist. Although

most masses that develop during pregnancy and lactation are benign, any

new mass should be evaluated promptly because of the possibility of

pregnancy-associated breast cancer (PABC). This is defined as malig-

nancy detected during pregnancy or within 1 year following preg-

nancy.141 Although PABC only represents approximately 3% of all breast

malignancies,142,143 the diagnosis of PABC deserves special consider-

ation because it involves both the mother and the fetus. It is veryimportant to recognize that breast cancer is not caused by pregnancy, but

can occur coincidentally with pregnancy.144

During pregnancy and lactation, the breast undergoes dramatic changes

in response to an increase in the circulating hormones estrogen, proges-

terone, and prolactin, which all have a proliferative effect on glandular

and ductal tissue.145 Early in the first trimester, estrogen and progesterone

secreted by the corpus luteum induce lobuloalveolar formation and

proliferating glandular epithelium, causing progressive branching of thelactiferous ducts. During the second trimester, placental estrogen induces

proliferation and differentiation of the alveolar epithelium into secretory

epithelium. Estrogen, progesterone, and prolactin cause the alveoli to

branch, resulting in enlargement of the breast. In the third trimester,

prolactin then stimulates milk production.146

All the physiological changes described lead to a diffuse and marked

increase in parenchymal density. The breast becomes firm and nodular to

palpation. Thus, the optimal time for a clinical breast examination toserve as a valuable screening tool in the detection of breast tumors is at

the first prenatal visit.147 When a mass is detected, the surgeon then has

the challenge of enacting the appropriate diagnostic algorithm and

expeditiously diagnosing the etiology of the mass. More than 90% of

women with PABC present with a breast mass.

Evaluation. The markedly increased parenchymal density of the breast

during pregnancy alters the traditional approach to a palpable mass in a

woman. At mammography, the gland appears very dense, heteroge-neously coarse, nodular, confluent, with a significant decrease in adipose

tissue and prominent ductal pattern142 (Fig 6). These features, along with

the high density usually noted in young women, decreases the sensitivity

of mammography to 62.5% to 68%, which ordinarily is up to 90%.148,149

Findings on mammography may be subtle, such as architectural distortion



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or asymmetrical densities; therefore, ultrasound is often recommended asthe first-line study to evaluate a palpable mass in a pr

Cirugia en El Embarazo

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