Gastrointestinal Disorders During Pregnancy




Key Abbreviations


Carcinoembryonic antigen CEA


Computed tomography CT


Crohn disease CD


Ectopic pregnancy EP


Esophagogastroduodenoscopy EGD


Gastroesophageal GE


Gastroesophageal reflux disease GERD


Human chorionic gonadotropin hCG


Hyperemesis gravidarum HG


Inflammatory bowel disease IBD


Irritable bowel syndrome IBS


Lower esophageal sphincter LES


Magnetic resonance imaging MRI


Nausea and vomiting of pregnancy NVP


Nonsteroidal antiinflammatory drug NSAID


Pelvic inflammatory disease PID


Peptic ulcer disease PUD


Small bowel obstruction SBO


Ulcerative colitis UC


Gastrointestinal (GI) complaints and disorders are common in women, including in their childbearing years, and thus often occur during pregnancy. These complaints and disorders present unique clinical challenges during pregnancy. First, the differential diagnosis during pregnancy is extensive. Aside from GI disorders unrelated to pregnancy, their complaints may be caused by obstetric or gynecologic disorders related to pregnancy or other intraabdominal diseases incidental to pregnancy. Moreover, some GI conditions—such as hyperemesis gravidarum (HG)—are unique to pregnancy. Second, the clinical presentation and natural history of GI disorders can be altered during pregnancy, as described below for appendicitis. Third, the diagnostic evaluation may need to be altered because of pregnancy. For example, radiologic tests and invasive examinations may raise concerns about their fetal safety during pregnancy. Fourth, the interests of both the mother and the fetus must be considered in therapeutic decisions during pregnancy. Usually, these interests do not conflict because what is good for the mother is generally good for the fetus. Sometimes, however, maternal therapy must be modified to substitute alternative but safer therapy because of concerns about drug teratogenicity (e.g., substituting a histamine 2 [H2]-receptor antagonist for misoprostol, an abortifacient that is contraindicated during pregnancy). Rarely, the maternal and fetal interests are diametrically opposed, as in the use of chemotherapy for maternal cancer, a therapy that can be life-saving to the mother but life-threatening to the fetus. These conflicts raise significant medical, legal, and ethical issues.


The obstetrician and gynecologist, as well as the gastroenterologist and surgeon, should be familiar with the medical and surgical GI conditions that can present in pregnancy and how these conditions affect and are affected by pregnancy. This chapter reviews GI symptoms and disorders during pregnancy with a focus on aspects of these disorders unique to pregnancy.




Physiologic Effects of Pregnancy on Abdominal Disorders


Abdominal assessment during pregnancy is modified by displacement of abdominal viscera by the expanding gravid uterus. For example, the location of maximal abdominal pain and tenderness from acute appendicitis migrates superiorly and laterally as the appendix is displaced by the growing gravid uterus. A rigid abdomen with rebound tenderness remains a valid indicator of peritonitis during pregnancy, but abdominal wall laxity and the interposition of the gravid uterus between the appendix and the anterior abdominal wall in late pregnancy may mask the classical signs of peritonitis. An abdominal mass may be missed on physical examination because of an enlarged, gravid uterus.


Many extraintestinal abdominal conditions or disorders are promoted by pregnancy. Mild hydronephrosis and hydroureter are common during pregnancy, particularly during the early third trimester, because of diminished muscle tone in the urinary tract from elevated progesterone levels and mechanical obstruction from uterine compression. Hydronephrosis in pregnancy is usually asymptomatic but can cause positional abdominal discomfort. Mucosal immunity may be attenuated during pregnancy as part of the physiologic immunologic tolerance for the foreign fetal antigens. This phenomenon, as well as urinary stasis during pregnancy, contributes to an increased rate of cystitis and pyelonephritis. Pregnancy also promotes cholelithiasis because of increased cholesterol synthesis and gallbladder hypomotility related to gestational hormones.


Pregnancy modifies GI physiology. Gastroesophageal reflux is promoted by gastric compression by the enlarged gravid uterus and by decreased lower esophageal sphincter tone due to increased serum progesterone and motilin levels during pregnancy. Pregnancy also increases the risk of aspiration of gastric contents for the same reasons, and gastric acid secretion may decrease as a result of increased progesterone levels. In addition, small bowel motility decreases during pregnancy. Constipation is promoted by decreased intestinal motility, mild intestinal compression by the enlarged gravid uterus, and increased recumbence from bed rest during pregnancy. Physiologic nausea and vomiting of pregnancy (NVP) is described below.


Physiologic alterations of laboratory values during pregnancy include, among others, mild leukocytosis, physiologic anemia of pregnancy, mild dilutional hypoalbuminemia, mildly increased alkaline phosphatase level, and electrolyte changes, particularly mild hyponatremia (see Appendix 1 , “Normal Values in Pregnancy”). The erythrocyte sedimentation rate is physiologically elevated and is a less reliable monitor of inflammatory activity during pregnancy. Gestational hormones, particularly estrogen, contribute to a mild hypercoagulopathy by increasing the synthesis of clotting factors. Thromboembolic phenomena are also promoted by intraabdominal vascular stasis from vascular compression by the enlarged gravid uterus.


The fetus poorly tolerates maternal hypotension, hypovolemia, anemia, and hypoxia. This intolerance affects the type and timing of therapy for abdominal disorders during pregnancy. The gravid uterus can compress the inferior vena cava in the supine position and thereby compromise venous return, aggravating systemic hypoperfusion from hypovolemia or GI bleeding. Simply turning the patient to the left side to displace the uterus may relieve this compression, improve venous return, and normalize the blood pressure. The heart rate increases by 10 to 15 beats/min during pregnancy, but the blood pressure normally declines modestly; therefore a rise in blood pressure during pregnancy may portend preeclampsia or eclampsia. Drugs that are normally safe and indicated in nonpregnant women must be evaluated in terms of fetal safety before administration during pregnancy.




Differential Diagnosis and Evaluation of Gastrointestinal Symptoms during Pregnancy


Physiologic changes during pregnancy may cause abdominal symptoms that include nausea, emesis, early satiety, bloating, pyrosis, and abdominal discomfort. Serious disorders that produce these symptoms may, therefore, be difficult to distinguish from physiologic changes during pregnancy. Significant symptoms should not be dismissed as normal during pregnancy without a careful history, physical examination, and appropriate evaluation.


Occasionally, the pregnancy is not known by the patient or is not revealed to the physician, particularly in early pregnancy, when physical findings are absent. The physician should be vigilant for possible pregnancy in a fertile woman with abdominal symptoms, particularly in the setting of missed menses, because pregnancy affects the differential diagnosis, clinical evaluation, and mode of therapy. Pregnancy tests should be performed early in the evaluation of significant abdominal symptoms in this situation.


Abdominal Pain


The differential diagnosis of abdominal pain during pregnancy is extensive in that it includes obstetric conditions in addition to the usual GI and other intraabdominal conditions in the general population. Abdominal discomfort without other symptoms or signs can be due to an enlarging uterus, fetal pressure against adjacent organs, and Braxton-Hicks uterine contractions associated with normal pregnancy. The abdominal pain is typically localized to the abdominal quadrant in which the afflicted organ is located, as illustrated for pain in the right lower quadrant in Box 48-1 . This general rule has occasional exceptions in nonpregnant patients because of referred pain from nearby regions, but it has more frequent exceptions during pregnancy because of displacement of viscera by the growing gravid uterus and referred or poorly localized pain from obstetric conditions.



Box 48-1

Differential Diagnosis of Right Lower Quadrant Abdominal Pain


Gastrointestinal Disorders





  • Appendicitis



  • Crohn disease



  • Ruptured Meckel diverticulum



  • Intestinal intussusception



  • Cecal perforation



  • Colon cancer



  • Ischemic colitis



  • Irritable bowel syndrome



Renal Diseases





  • Nephrolithiasis



  • Cystitis



  • Pyelonephritis



Obstetric and Gynecologic Diseases





  • Ruptured ectopic pregnancy



  • Ovarian tumors



  • Ovarian cyst rupture



  • Ovarian torsion



  • Endometriosis



  • Uterine leiomyomas



Other





  • Trochanteric bursitis




In the medical history, the pain intensity, nature, temporal pattern, radiation, exacerbating factors, and alleviating factors help narrow the differential diagnosis. Abdominal pain increases progressively in appendicitis but is nonprogressive in viral gastroenteritis. The pain from obstruction of the small intestine may be intermittent but is severe, and renal and biliary colic also produce a waxing and waning intensity of pain. Acute cholecystitis is associated with RUQ pain as well as pain referred to the right shoulder. The pain of acute pancreatitis is often boring in quality, located in the abdominal midline, and radiates to the back. Careful physical examination of the abdomen that includes inspection, palpation, and auscultation can further pinpoint the etiology. Laboratory evaluation of significant abdominal pain routinely includes a complete blood count, serum electrolytes, and liver function tests and often includes a leukocyte differential, coagulation profile, and serum lipase determination. In evaluating the laboratory results, gestational changes in normative values, as mentioned earlier, must be considered. Radiologic tests may be extremely helpful diagnostically.


When the diagnosis is uncertain, close and vigilant monitoring by a surgical team with frequent abdominal examination and regular laboratory tests can often clarify the diagnosis. The character, severity, localization, or instigating factors of abdominal pain often change with time. For example, acute appendicitis typically changes from a dull, poorly localized, moderate pain to an intense and focal pain as the inflammation extends from the appendiceal wall to the surrounding peritoneum. The differential diagnosis of severe abdominal pain is described in Table 48-1 .



TABLE 48-1

COMMON CAUSES OF ACUTE, SEVERE ABDOMINAL PAIN DURING PREGNANCY: PAIN CHARACTERISTICS AND DIAGNOSTIC TESTS




















































CONDITION LOCATION CHARACTER RADIATION DIAGNOSTIC TESTS
Ruptured ectopic pregnancy Lower abdomen or pelvis Localized, severe None Serum β-hCG, abdominal ultrasound
Pelvic inflammatory disease Lower abdomen or pelvis Gradual in onset, localized Flanks and thighs Abdominal ultrasound
Appendicitis First periumbilical, later RLQ (RUQ in late pregnancy) Gradual in onset, becomes focal Back or flank Abdominal ultrasound in appropriate clinical setting
Acute cholecystitis RUQ Focal Right scapula, shoulder or back Abdominal ultrasound, serum liver function tests
Pancreatitis Epigastric Localized, boring Middle of back Serum lipase and amylase, abdominal ultrasound
Perforated peptic ulcer Epigastric or RUQ Burning, boring Right back Abdominal ultrasound, laparotomy
Urolithiasis Abdomen or flanks Varies from intermittent and aching to severe and unremitting Groin Urinalysis, abdominal ultrasound, and occasionally fluoroscopy with contrast urography

hCG, human chorionic gonadotropin RLQ, right lower quadrant; RUQ, right upper quadrant.


GI causes of abdominal pain are discussed below under their individual headings in this chapter, and hepatobiliary causes are discussed in the prior chapter on hepatic disorders. Obstetric causes of abdominal pain are also prominent during pregnancy. Ectopic pregnancy (EP) classically presents with abdominopelvic pain and vaginal bleeding after a period of amenorrhea. The pain may initially be diffuse and vague but later becomes focal and severe. Physical signs include mild uteromegaly, cervical tenderness, and an adnexal mass. EP is often differentiated from a viable intrauterine pregnancy by serial beta–human chorionic gonadotropin (β-hCG) determinations, but it is better differentiated from intrauterine pregnancy by transabdominal or transvaginal pelvic ultrasonography with simultaneous β-hCG determination. Rupture of an ectopic pregnancy often presents with abdominal pain, rebound tenderness, and hypotension.


In an abdominal (heterotopic) pregnancy, the abdominal pain is associated with signs of abdominal tenderness; a closed, noneffaced cervix; and a palpable mass distinct from the uterus. Sonography and other radiologic modalities, as well as serial β-hCG determinations, are used to detect and localize the pregnancy. Abdominal pain is the most common symptom of heterotopic pregnancy. Abdominal ultrasound is sometimes diagnostic, but laparotomy may be required for the diagnosis.


The lower abdominal pain associated with preterm labor is characteristically associated with vaginal discharge or spotting. Back pain and vaginal pressure commonly occur. The diagnosis is made by cervical examination, either by transvaginal ultrasound or digitally. The abdominal pain from spontaneous abortion— whether threatened, incomplete, or complete—tends to be mild to moderate, crampy, and diffuse and is typically associated with vaginal bleeding. Placenta previa sometimes presents with abdominal pain or painful uterine contractions in late pregnancy. Vaginal hemorrhage is, however, the predominant symptom. Sonography is usually diagnostic. Although placental abruption commonly causes abdominal pain, it is typically distinguished from GI disorders by the presence of vaginal bleeding. Patients typically exhibit uterine tenderness and frequent uterine contractions. Uterine rupture usually presents in laboring women with abnormal fetal heart rate recordings or fetal death, uterine tenderness, peritoneal irritation, hypotension, and vaginal bleeding.


Severe preeclampsia can present with right upper quadrant (RUQ) pain and elevated serum transaminase levels. Patients exhibit hypertension and proteinuria that starts after 20 weeks’ gestation. Patients with hemolysis, elevated liver enzymes, and low platelets (HELLP) syndrome often have epigastric or RUQ pain. Patients have hemolysis with a microangiopathic peripheral blood smear, elevated liver transaminase levels, and thrombocytopenia. Acute fatty liver of pregnancy (AFLP) often presents with abdominal pain, nausea and vomiting, anorexia, and jaundice. Liver biopsy demonstrates intracytoplasmic microsteatosis in hepatocytes. The definitive treatment for these three pregnancy-related conditions of preeclampsia, HELLP syndrome, and AFLP is prompt delivery after maternal stabilization, provided that the fetus is sufficiently mature (see Chapters 31 and 47 ).


Choriocarcinoma , a malignant trophoblastic proliferation, typically presents with an abdominal mass and vaginal bleeding but may cause abdominal pain. The symptoms usually occur after term pregnancy, abortion, or incomplete evacuation of a hydatidiform mole. The diagnosis is suggested by persistently elevated β-hCG levels in the absence of pregnancy.


Gynecologic disorders are also in the differential of abdominal pain during pregnancy. The lower abdominal pain from pelvic inflammatory disease (PID) is typically associated with pyrexia and vaginal discharge. Hemorrhagic infarction of large uterine leiomyomas (fibroids), called the painful myoma syndrome, is characterized by severe abdominal pain, nausea, emesis, pyrexia, and uterine bleeding. Ultrasonography or magnetic resonance imaging (MRI) is usually diagnostic. The abdominal pain of a tuboovarian abscess is frequently associated with a palpable lower abdominal mass, pyrexia, and leukocytosis. Patients often have risk factors such as prior pelvic surgery, assisted reproduction, or PID. MRI or sonography is helpful in the diagnosis, but laparoscopy is often required for confirmation.


Adnexal torsion typically causes lower abdominal pain that is sharp and sudden in onset. Signs include unilateral lower quadrant tenderness, a palpable adnexal mass, cervical tenderness, or rebound tenderness from peritonitis. Ultrasonography, including duplex scanning, is valuable in the detection of adnexal masses, particularly cysts. The abdominal pain from early ovarian cancer tends to be vague and diffuse. Patients may also complain of abdominal distension and urinary frequency. Abdominal sonography is highly sensitive at mass detection but is insufficiently accurate at distinguishing malignant from benign ovarian lesions. Surgery may be required to confirm the diagnosis and for definitive therapy.


The differential of abdominal pain during pregnancy also includes renal disorders. Symptoms from cystitis may include suprapubic discomfort without frank abdominal pain, but patients usually have urinary frequency, urgency, or dysuria. The diagnosis is made by urinalysis and urine culture in the appropriate clinical setting. Symptoms from acute pyelonephritis include pyrexia, chills, nausea, emesis, and flank pain. The pain may radiate to the abdomen or pelvis and may cause costovertebral tenderness. Patients often have risk factors such as nephrolithiasis, recurrent lower urinary tract infections, diabetes mellitus, or congenital ureteral abnormalities. The diagnosis is usually made by urine and blood cultures in the appropriate clinical setting. Renal ultrasound is performed in patients who fail to respond clinically within 3 days of instituting therapy or who have recurrent infection. The abdominal pain from urolithiasis typically radiates from the back or abdomen to the groin. Other symptoms include gross hematuria, nausea, emesis, urinary urgency, and urinary frequency. Ultrasonography is the standard initial diagnostic test during pregnancy.


Patients with sickle cell hemoglobinopathies that include hemoglobin SS, hemoglobin SC, and hemoglobin S/β-thalassemia are prone to sickle cell crises during pregnancy. Patients are usually black, and the abdominal pain in sickle cell crisis can be excruciating.


Upper Gastrointestinal Symptoms


Nausea and Vomiting


Nausea and vomiting during pregnancy is most commonly because of NVP or HG, idiopathic disorders without demonstrable mucosal or mural disease. The differential diagnosis of nausea and vomiting includes many other conditions ( Box 48-2 ). NVP should be diagnosed only after exclusion of organic disorders by the history, physical findings, blood tests, and appropriate diagnostic studies. Misdiagnosis of nausea and vomiting as NVP, rather than more severe diseases, can be catastrophic. However, the great majority of nausea and vomiting during the first half of pregnancy is from NVP.



Box 48-2

Differential Diagnosis of Nausea and Vomiting During Pregnancy





  • Nausea and vomiting of pregnancy



  • Hyperemesis gravidarum



  • Pancreatitis



  • Symptomatic cholelithiasis



  • Viral hepatitis



  • Peptic ulcer disease



  • Gastric cancer



  • Intestinal obstruction



  • Intestinal pseudoobstruction



  • Gastroparesis diabeticorum



  • Gastritis



  • Gastroesophageal reflux disease



  • Acute pyelonephritis



  • Drug toxicity



  • Vagotomy



  • Preeclampsia/eclampsia



  • Acute fatty liver of pregnancy



  • Hemolysis, elevated liver enzymes, and low platelets (HELLP syndrome)



  • Anorexia nervosa/bulimia



  • Other neuropsychiatric disorders




Dyspepsia or Pyrosis


The differential diagnosis of dyspepsia or pyrosis (heartburn) during pregnancy is listed in Box 48-3 . During pregnancy, gastroesophageal reflux disease (GERD) is extremely common, whereas peptic ulcer disease (PUD) is relatively uncommon. The diagnosis of GERD, rather than PUD, is suggested by pain that radiates substernally, or pain exacerbated by drinking acidic citrus drinks, or recumbency. Symptoms include water brash or regurgitation of an excessive amount of acidic saliva and the presence of extraintestinal manifestations, including nocturnal asthma, hoarseness, laryngitis, or periodontal disease. Patients with dyspepsia or pyrosis during pregnancy can usually be managed symptomatically without undergoing diagnostic esophagogastroduodenoscopy (EGD), as discussed below.



Box 48-3

Differential Diagnosis of Dyspepsia or Pyrosis During Pregnancy





  • Gastroesophageal reflux disease



  • Peptic ulcer disease



  • Nausea and vomiting of pregnancy



  • Hyperemesis gravidarum



  • Pancreatitis



  • Biliary colic



  • Acute cholecystitis



  • Viral hepatitis



  • Appendicitis



  • Acute fatty liver of pregnancy (in late pregnancy)



  • Irritable bowel syndrome/nonulcer dyspepsia




Hematemesis


Upper GI bleeding is uncommon, but not rare, during pregnancy because pregnant patients are generally relatively young adults. NVP increases the risk of hemorrhage from a Mallory-Weiss tear, and decreased lower esophageal sphincter (LES) pressure and increased intragastric pressure during pregnancy promote gastroesophageal reflux that can cause hemorrhage. The most common causes of GI hemorrhage during pregnancy are GERD, gastritis, Mallory-Weiss tears, and ulcers. Unusual causes include esophageal varices and gastric cancer. Patients with upper GI bleeding that causes hemodynamic instability are approached much the same as nonpregnant patients but with a few exceptions. In the general population, the hematocrit is not a reliable indicator of the severity of bleeding because of the lag between blood loss and the decline in the hematocrit. The hematocrit is an even less reliable indicator of bleeding severity during pregnancy because of the conflicting effects of intravascular fluid accumulation and increased erythrocyte mass during normal pregnancy. Maternal blood pressure is not a reliable indicator of fetal well-being. Fluid, including transfusions of packed erythrocytes when indicated, should be aggressively administered to pregnant patients with acute GI bleeding because of the extraordinary fetal sensitivity to hypoperfusion, the difficulty in assessing volume status during pregnancy, and the usually satisfactory cardiac function of pregnant patients.


Dysphagia


The differential of dysphagia during pregnancy is similar to that in the general adult population, except that esophageal cancers are uncommon in these relatively young adults. Pregnant patients with acquired immunodeficiency syndrome (AIDS) can have dysphagia or painful swallowing, odynophagia, from esophageal candidiasis or esophageal lymphoma. Dysphagia from a peptic stricture is uncommon in pregnant patients, despite their high frequency of GERD, because their GERD is typically short term and moderate. Achalasia is a motility disorder that typically presents with a high resting LES pressure, failure of the LES to relax with swallowing, nonperistaltic esophageal muscle contractions, dysphagia, and weight loss.


Definitive therapy for severe dysphagia is best performed before, rather than during, pregnancy to assure adequate nutrition during gestation, a paramount concern for normal fetal development. Thus surgery for severe achalasia or other benign esophageal diseases should be performed before pregnancy.


Lower Gastrointestinal Symptoms


Diarrhea


The pathogenesis and differential diagnosis of diarrhea in pregnant women is similar to that in the nonpregnant population. Acute diarrhea is usually caused by viral, bacterial, or parasitic enteropathogens. Viral agents, such as rotavirus and Norwalk virus, typically cause an acute self-limited diarrhea with upper GI symptoms and rare long-term sequelae. Bacterial causes of diarrhea include Campylobacter, Shigella, pathogenic Escherichia coli , and Salmonella. Pseudomembranous colitis from Clostridium difficile infection must be considered in the differential diagnosis when the diarrhea starts after antibiotic administration. Bacterial pathogens tend to produce frequent, small-volume stools, abdominal pain, and pyrexia. Inflammation of intestinal mucosa may produce fecal blood or leukocytes. Bacterial colitis is usually diagnosed by stool analysis and stool cultures. Pregnant patients with advanced human immunodeficiency virus (HIV) infection are prone to opportunistic enteric bacterial, fungal, parasitic, and viral infections, which often cause diarrhea. Noninfectious causes of diarrhea include medications, functional causes, food intolerances, and inflammatory bowel disease (IBD); in addition, hyperthyroidism can cause hyperdefecation. The initial management of severe acute diarrhea includes intravenous (IV) hydration, correction of electrolyte disorders, and consideration of discontinuing oral feedings. Stool studies include bacterial culture and sensitivity, ova and parasites, C . difficile toxin, and fecal leukocytes. Flexible sigmoidoscopy can be considered despite pregnancy for persistent refractory diarrhea if the stool studies are unrevealing. Reversal of nutritional deficiencies from profound acute or chronic diarrhea is especially important during pregnancy to maintain fetal well-being.


Constipation


Constipation is very common in pregnant women and affects up to one-fourth of this population. Pregnancy tends to promote constipation from poor fluid intake due to nausea and vomiting, iron supplementation, decreased patient mobility, slowed GI transit predominantly from the effects of progesterone, and GI compression by the enlarged gravid uterus.


General measures can reverse these constipating factors during pregnancy. Adequate fluid intake and moderate exercise are important. Increased fiber intake—either by increasing dietary fiber, such as with wheat bran or psyllium husks, or by administering medications such as methylcellulose—is recommended to promote stool bulk and softness. Patients should be advised to defecate in the morning or after meals when colonic motor activity is stimulated via the gastrocolonic reflex. Sorbitol and lactulose, poorly absorbed sugars that cause an osmotic diarrhea, may be effective for constipation during pregnancy; however, they may cause abdominal bloating and flatulence. They should be used with caution in patients with diabetes, and they should be avoided in pregnant patients with nausea because they can exacerbate this symptom. Stimulant laxatives such as senna or bisacodyl may be considered in patients with severe constipation who fail to respond to conservative measures, bulk laxatives, or osmotic laxatives. Laxatives to be avoided during pregnancy include castor oil, because it may initiate premature uterine contractions, and hypertonic saline laxatives such as phospho soda, because they promote sodium and water retention, which is inadvisable during pregnancy; in addition, they may cause renal failure in patients who are dehydrated or have preexisting renal insufficiency. Rarely, constipation is the first manifestation of severe GI disease during pregnancy.


Red Blood Per Rectum


Hemorrhoids are the most common cause of rectal bleeding during pregnancy. Other causes in the differential diagnosis include ulcerative colitis (UC), Crohn disease (CD), a rectal fissure, and infectious colitis as well as unusual diagnoses during pregnancy such as diverticular bleeding, bowel ischemia, or colon cancer.




Diagnostic Testing during Pregnancy


Radiologic Imaging


Fetal safety during diagnostic imaging is a concern for pregnant patients and pregnant medical personnel. Ultrasonography is considered safe during pregnancy and is the preferred imaging modality for abdominal pain during pregnancy. Unfortunately, test sensitivity depends on operator technique, patient cooperation, and the patient’s anatomy in that sensitivity is decreased by abdominal fat and intestinal gas (see Chapter 9 ). MRI is preferable to computed tomography (CT) during pregnancy to avoid ionizing radiation, and gadolinium administration should be avoided if feasible during MRI in the first trimester. Rapid-sequence MRI is preferable to conventional MRI because of briefer exposure. The patient should undergo counseling before diagnostic roentgenography.


Data concerning fetal malformations, growth restriction, and mortality from ionizing radiation are derived from past experience, particularly from survivors of the atomic bombs in Japan and the nuclear accident in Chernobyl. Radiation can cause chromosomal mutations and neurologic abnormalities, including mental retardation, and it moderately increases the risk of childhood leukemia. Radiation dosage is the most important risk factor, but fetal age at exposure and proximity to the radiation source are also important factors (see Chapter 8 ). Diagnostic studies with the most radiation exposure, such as IV pyelography or barium enema, typically expose the fetus to less than 1 rad. Thus one diagnostic fluoroscopic procedure is safe in pregnancy. In decisions regarding roentgenographic tests, the risks from radiation exposure must be weighed against the benefits of diagnosing a severe condition. Fetal radiation exposure should be minimized by fetal shielding, collimation, and rapid-sequence studies. Consultation with a radiation physicist may help reduce radiation exposure. Adverse fetal effects from iodinated contrast have not been reported, and these contrast materials can be used when indicated. The safety of radiologic abdominal imaging during pregnancy is briefly summarized in Table 48-2 .



TABLE 48-2

GENERAL PRINCIPLES REGARDING ABDOMINAL IMAGING TESTS DURING PREGNANCY



















TEST SAFETY DURING PREGNANCY
Abdominal ultrasound Considered safe and is the preferred imaging modality during pregnancy; unfortunately, this test is less sensitive and less specific than other imaging modalities for many abdominal disorders
Magnetic resonance imaging Considered safe; some avoid administering gadolinium, but no firm evidence of teratogenicity or other harm exists
Radiographs Single radiographs entail a small but acceptable fetal risk; limit fetal radiation exposure by shielding, collimation, rapid-sequence studies, and modern x-ray equipment
Computed tomography Consider magnetic resonance imaging as alternative when abdominal ultrasound is nondiagnostic. Computed tomography may be required in rare circumstances (e.g., to avoid surgery for possible but unproven appendicitis) and is safe if not repeated several times. Consult with a radiation physicist to minimize fetal radiation exposure


Endoscopy During Pregnancy


Endoscopy is often performed in the evaluation of abdominal symptoms in nonpregnant patients. Flexible sigmoidoscopy is used to evaluate minor lower GI complaints including rectal symptoms, whereas EGD is performed to evaluate epigastric pain, dyspepsia, or pyrosis. Although endoscopy is extremely safe in the general population, endoscopy during pregnancy raises the unique issue of fetal safety. Endoscopy could potentially cause fetal complications from the medications used, placental abruption or fetal trauma during endoscopic intubation, cardiac arrhythmias, systemic hypotension or hypertension, and transient hypoxia. The teratogenicity of medications is of particular concern in the first trimester during organogenesis.


Sigmoidoscopy seems to be relatively safe during pregnancy. No woman suffered endoscopic complications in a study of 46 patients undergoing sigmoidoscopy during pregnancy. Excluding one unknown pregnancy outcome and four voluntary abortions, 38 of 41 pregnant women delivered healthy infants, including 27 at full term. Study patients did not have a worse outcome than pregnant controls matched for sigmoidoscopy indications who did not undergo sigmoidoscopy in terms of mean infant Apgar scores at birth, the rates of fetal or neonatal demise, premature delivery, low birthweight, and delivery by cesarean section. Additionally, no endoscopic complications were reported in 13 flexible sigmoidoscopies during pregnancy analyzed by a mailed survey of 3300 gastroenterologists. All pregnancies resulted in delivery of healthy infants at term.


These studies, in addition to scattered case reports, strongly suggest that sigmoidoscopy during pregnancy does not induce labor or cause congenital malformations and should be strongly considered in medically stable patients with clear indications. Sigmoidoscopy is not recommended during pregnancy for questionable indications, such as routine cancer screening or surveillance, which can be deferred until at least 6 weeks postpartum. Sigmoidoscopy should be performed with careful maternal monitoring that includes electrocardiography (ECG), blood pressure, and pulse oximetry after obstetric consultation and medical stabilization. Analgesic medication should be minimized during sigmoidoscopy, especially during the first trimester.


Data are currently limited on colonoscopy during pregnancy. The two largest studies comprised 20 and 8 pregnant patients. In the study of 20 pregnant patients, 16 colonoscopies were performed during the second trimester. Excluding one successful therapeutic colonoscopy to decompress a severely dilated colon from colonic pseudoobstruction, colonoscopy was diagnostic in 10 of 19 cases, which included diagnoses of ulcerative, ischemic, Crohn, and lymphocytic colitis. Colonoscopy led to therapeutic changes in the management of seven patients, and two minor maternal procedural complications of mild transient hypotension occurred without clinical sequelae. Fetal outcomes were generally favorable: all infants were born healthy except for one spontaneous abortion and one infant born with congenital defects.


Colonoscopy should be considered, particularly during the second trimester, for very strong indications—such as suspected colon cancer—after obtaining informed consent that includes the theoretic but unsubstantiated fetal risks of colonoscopy. Colonoscopy should be considered questionable during the first trimester, even though at times it can be justified for extremely clear indications. A polyethylene glycol (PEG) balanced electrolyte solution is generally preferred over a sodium phosphate (Fleet phospho soda) solution to cleanse the colon for colonoscopy because sodium phosphate is associated with renal failure or electrolyte abnormalities in dehydrated or otherwise at-risk patients. Colonoscopic tattooing of colonic lesions is performed using India ink or methylene blue in the nonpregnant population, but methylene blue should not be used during pregnancy because of potential fetotoxicity.


EGD is relatively safe for the fetus and the pregnant mother. In a case-controlled study of 83 EGDs performed during pregnancy at a mean gestational age of 20 weeks, the indications for EGD included GI bleeding in 37, abdominal pain in 28, vomiting in 14, and other indications in 4. EGD did not cause any maternal complications and did not lead to labor. Excluding 6 voluntary abortions and 3 unknown pregnancy outcomes, 70 of 74 patients (95%) delivered healthy infants. In this study, the four adverse pregnancy outcomes—three stillbirths or deaths from severe prematurity and one involuntary abortion—occurred in high-risk pregnancies and were unrelated to EGD temporally or etiologically. No liveborn infant had any congenital malformation noted in the neonatal nursery. The pregnancy outcome in study patients included the mean Apgar scores at 1 and 5 minutes and the frequency of low birthweight, infant deaths, congenital defects, and delivery by cesarean section and was not statistically significantly different from the mean scores or rates in a group of 48 pregnant controls matched for EGD indications who did not undergo EGD because of their pregnancy. The two patient groups had similar pregnancy outcomes even though the study patients generally were sicker and had a stronger indication for EGD than the controls. This study and two other studies of 60 pregnant patients undergoing EGD during the first trimester and of 30 pregnant patients undergoing EGD during pregnancy suggest that EGD is at least as safe as not performing the procedure in pregnant patients with a strong indication for EGD. Similar results were noted in a report of 73 pregnant patients who underwent EGD, analyzed by a mailed survey of 3300 gastroenterologists.


EGD is recommended during pregnancy for hemodynamically significant upper GI bleeding. It is rarely helpful, and rarely necessary, for nausea and vomiting or even HG during pregnancy. EGD is reserved for atypical situations, such as severe and refractory nausea and vomiting accompanied by significant abdominal pain, hematemesis, or signs of gastroduodenal obstruction. EGD is neither necessary nor indicated to evaluate typical symptoms of GERD during pregnancy and should be reserved for cases when the presentation is atypical and severe, when the condition is refractory to intense pharmacologic therapy, when esophageal surgery is contemplated, and when complications such as GI bleeding or dysphagia supervene. EGD is useful in diagnosing complicated PUD, including gastric outlet obstruction, malignant gastric ulcer, refractory ulcer, and persistently bleeding ulcer. EGD should be performed in relatively stable patients with ECG monitoring after obstetric consultation and after normalization of vital signs, which may require transfusion of packed erythrocytes and supplemental oxygenation. Fetal monitoring should be performed at a gestational age when intervention for nonreassuring fetal status would be considered. Informed consent is particularly important during pregnancy. The patient should be informed of the benefits and apparent safety of endoscopy, but she should also be cautioned that the potential fetal risks are incompletely characterized. General measures to increase the risk/benefit ratio of endoscopy during pregnancy are listed in Table 48-3 .



TABLE 48-3

GENERAL PRINCIPLES TO IMPROVE THE RISK/BENEFIT RATIO OF GASTROINTESTINAL ENDOSCOPY DURING PREGNANCY




























PRINCIPLE EXAMPLE
Perform endoscopy only for strong indications Colonoscopy for suspected colon cancer
Avoid endoscopy or defer it until delivery for weak or elective indications Colonoscopy for routine colon cancer screening
Use the safest drugs (Food and Drug Administration category B preferable or at most category C) in the lowest possible dosages for sedation and analgesia Propofol (category B) or fentanyl (category C) but not diazepam (category D) because of possible, albeit unlikely, association with congenital cleft palate
Consult an anesthesiologist regarding drug safety during pregnancy Monitored anesthesia care (MAC) with anesthesiologist present during endoscopy
It is preferable to perform endoscopy in the second trimester, if possible, to avoid potential teratogenicity during fetal organogenesis in the first trimester and to avoid premature labor or adverse effects on the neonate after delivery in the third trimester If possible, defer endoscopy during the first trimester until the second trimester, and defer endoscopy during the third trimester until after delivery.
Minimize procedure time Performed by an experienced, expert endoscopist
Obstetric support should be available for a pregnancy-related procedure complication Performed in an in-hospital endoscopy suite rather than a physician’s office or ambulatory surgical center

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Mar 31, 2019 | Posted by in OBSTETRICS | Comments Off on Gastrointestinal Disorders During Pregnancy
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