This chapter deals primarily with APGO Educational Topic Area:
TOPIC 17 MEDICAL AND SURGICAL COMPLICATIONS OF PREGNANCY
Students should be able to identify how pregnancy affects the natural history of various gastrointestinal, renal, and surgical disorders and how a preexisting gastrointestinal or renal disorder affects maternal and fetal health. They should be able to describe gastrointestinal disorders unique to pregnancy. They should be able to outline a basic approach to evaluation and management of gastrointestinal, renal, and surgical disorders in pregnancy.
Clinical Case
You are seeing a new patient in your office who is complaining of frequent nausea and vomiting over the past few weeks. She recently found out she is pregnant. She has had to miss several days of work due to the vomiting and is worried that she is ill. She was seen by another physician who did some blood tests and told her she needed to be treated for hyperthyroidism. She is concerned about taking anything to help relieve her symptoms or to treat her thyroid disorder because she knows that many medications can cause birth defects.
Maternal medical or surgical conditions can complicate the course of a pregnancy and can be affected by pregnancy. Physicians providing obstetric care must have a thorough understanding of the effect of pregnancy on the natural course of a disorder, the effect of the disorder on a pregnancy, and the change in management of the pregnancy and disorder caused by their coincidence.
GASTROINTESTINAL DISORDERS
The normal anatomical, physical, and functional changes that occur in the gastrointestinal (GI) tract in normal pregnancy can appreciably alter clinical findings or symptoms typically used for diagnosis of GI diseases (see Chapter 5). In addition, the implications of these signs and symptoms may change depending on the time of onset during the pregnancy (see Section “Nausea and Vomiting of Pregnancy”). Several disorders of the liver are unique to pregnancy including intrahepatic cholestasis of pregnancy (ICP), acute fatty liver of pregnancy, and preeclampsia/HELLP syndrome. Prompt diagnosis and appropriate management of these disorders are essential in preventing potentially serious adverse outcomes for the mother and fetus. Viral hepatitis is covered in Chapter 24. Management of cholelithiasis, cholecystitis, and appendicitis is covered later in this chapter in Section “Surgical Conditions.”
Nausea and Vomiting of Pregnancy
Symptoms of nausea and vomiting are common in pregnancy (see Chapters 5 and 6), especially in the first trimester, and affect 70% to 85% of pregnant women. Because symptoms of nausea and vomiting of pregnancy (NVP) are so common, clinicians and pregnant women may minimize their importance and fail to offer or seek treatment. NVP may significantly impact the daily life of a pregnant woman, making it difficult for her to function at home or at work. Safe and effective treatment, in the form of dietary or lifestyle changes as well as pharmacological therapies, is available and should be offered.
Although the etiology of NVP is unknown, the timing is associated with the typical early pregnancy rise in human chorionic gonadotropin ([hCG] Fig. 21.1) as well as the higher estrogen and progesterone levels noted in pregnancy. Most women with NVP begin having symptoms before 9 weeks of gestation, with the peak in severity occurring between 7 and 12 weeks of gestation. The most severe form of NVP, hyperemesis gravidarum, occurs in 0.5% to 2% of pregnancies and is associated with ketonuria, dehydration, and significant weight loss (>5% prepregnancy weight). Hyperemesis gravidarum is the most common indication for hospital admission in the first half of pregnancy.Fortunately, 85% to 90% of women will stop experiencing symptoms of NVP by 16 weeks of gestation, with a very small proportion having persistent symptoms beyond 20 weeks. Women with multiple gestation, molar pregnancy, and family history or personal history of hyperemesis gravidarum in a prior pregnancy are at increased risk for NVP.
FIGURE 21.1. Nausea symptoms and human chorionic gonadotropin (hCG) levels by week of gestation. NVP, nausea and vomiting of pregnancy. Association of Professors of Gynecology and Obstetrics (APGO) Educational Series on Women’s Health, “Nausea and Vomiting of Pregnancy,” 2011.
Symptoms
Symptoms of NVP can occur at any time of the day or night so the term “morning sickness” can be misleading. NVP can be classified as mild (nausea only), moderate (nausea with retching and/or vomiting), or severe (nausea and persistent vomiting leading to dehydration). However, even mild NVP may be perceived by some women as having a significant impact on their daily life. Therefore, NVP may be best classified according to the impact on a pregnant woman’s daily family life or employment; this assessment of impact should guide the need for intervention. Other than quality of life and productivity, NVP has limited negative impact on outcomes of pregnancy; women with severe NVP or hyperemesis gravidarum and poor total weight gain during the pregnancy may be at increased risk for delivering an infant with lower birth weight compared with women with milder NVP or no symptoms. However, miscarriage rates are statistically lower in women with NVP compared with women without symptoms.
Diagnosis
NVP is essentially a diagnosis of exclusion, with the time of onset of symptoms in pregnancy being an important clue; onset of symptoms at >9 weeks of gestation and especially in the second half of pregnancy should prompt evaluation for diagnoses other than NVP. In addition, certain physical examination findings suggest a diagnosis other than NVP (Box 21.1). Conditions that should be considered in the differential diagnosis of NVP are listed in Box 21.2. A careful history will identify underlying medical disorders; this information combined with physical examination findings not consistent with NVP will direct the need for laboratory or other diagnostic evaluation. An ultrasound to evaluate for multiple gestation or molar pregnancy should be included in the evaluation if not previously documented. A “biochemical hyperthyroidism” has been associated with NVP due to the action of hCG on the thyroid-stimulating hormone receptor. Hyperthyroidism as a cause of NVP is very rare; if there are no overt signs of thyroid disease such as goiter, routine thyroid function tests are not indicated. NVP cannot be attributed to underlying psychological or psychiatric disorders although the symptoms of NVP may exacerbate these problems.
BOX 21.1 Physical Examination Findings Not Characteristic of Nausea and Vomiting of Pregnancy
Abdominal pain or tenderness (other than mild epigastric discomfort)
Fever
Headache
Abnormal neurological examination
Goiter
Treatment
If symptoms of NVP are impacting the daily life and functioning of a pregnant woman, some form of intervention should be offered and instituted. Fear of teratogenicity may cause providers or pregnant women to avoid drug therapy for NVP; this is unwarranted insofar as safe and effective medical treatments are readily available. In addition, treatment of milder symptoms of NVP may prevent progression to more severe symptoms and hyperemesis gravidarum. Management of NVP includes dietary and lifestyle modifications (Box 21.3) as well as pharmacologic therapies (Fig. 21.2). First-line therapy should be vitamin B6 with or without doxylamine. Effective and safe treatments for more serious cases include antihistamine H1-receptor blockers, phenothiazines, and benzamides.
HEPATIC DISORDERS UNIQUE TO PREGNANCY
Intrahepatic Cholestasis of Pregnancy
ICP is characterized by generalized pruritus (but no definitive rash) with elevated serum bile acids that typically occurs in the second half of pregnancy and resolves after delivery. This disorder occurs in 0.5% to 1.5% of pregnancies in the United States and Europe but in much higher rates (4%–10%) in other areas of the world (Bolivia and Chile). The cause of ICP is unknown but likely involves genetic and hormonal factors. Recurrence is common in subsequent pregnancies. Maternal morbidity is low, with the main effect being discomfort from the intense itching, which is generalized but often involves the palms of the hands and soles of the feet. Fetal effects can be serious, with increased risk of stillbirth. Diagnosis is confirmed by the presence of elevated fasting levels of bile acids. Other laboratory abnormalities may include mild elevations in serum aminotransferases and total and direct bilirubin concentrations.
BOX 21.2 Differential Diagnosis of Nausea and Vomiting of Pregnancy
Gastrointestinal Disorders
Gastroenteritis
Gastroparesis
Gallbladder and biliary tract disease
Hepatitis
Bowel obstruction
Peptic ulcer disease
Pancreatitis
Appendicitis
Genitourinary Tract Conditions
Pyelonephritis
Ovarian torsion
Kidney stones
Metabolic Disease
Diabetic ketoacidosis
Porphyria
Addison disease
Hyperthyroidism
Neurologic Disorders
Pseudotumor cerebri
Migraines
Tumors of the central nervous system
Miscellaneous
Drug toxicity
Psychologic and psychiatric disorders
Pregnancy-Related Conditions
Acute fatty liver of pregnancy
Preeclampsia
Modified from APGO monograph “Nausea and Vomiting of Pregnancy,” 2011 and American College of Obstetricians and Gynecologists. Nausea and Vomiting of Pregnancy. ACOG Practice Bulletin No. 52. Washington, DC: American College of Obstetricians and Gynecologists; 2004;103:803–815 (Reaffirmed 2011).
Treatment
Treatment consists of ursodeoxycholic acid, which decreases plasma bile acid concentrations and improves the symptoms of itching. Decreased levels of bile acids reduce the risk of adverse outcome, but there are no current studies documenting decreased perinatal morbidity and mortality with treatment. Once the diagnosis of ICP is made, antepartum fetal surveillance is initiated. It is not clear whether available methods of antepartum surveillance reliably predict fetal compromise in the setting of ICP. Therefore, assessment of pulmonary maturity by amniocentesis is generally recommended at 36 weeks of gestation, with delivery once mature fetal lung status is documented.
BOX 21.3 Dietary and Lifestyles Measures for Managing Symptoms of Nausea and Vomiting of Pregnancy
• Eating frequently in small amounts
• Eating high-carbohydrate, low-fat foods
• Eating protein predominant meals
• Eating a bland, dry diet
• Drinking small amounts of cold, clear carbonated or sour liquids
• Drinking between meals rather than with meals
• Lying down as needed; getting plenty of rest
• Changing position slowly, especially when rising
• Going outside for fresh air as needed
• Avoiding offensive foods and smells
• Not brushing teeth after eating
Modified from APGO monograph NVP 2011.
Acute Fatty Liver of Pregnancy
The most common cause of acute liver failure in pregnancy is acute fatty liver. It is characterized by microvesicular fatty infiltration of hepatocytes most typically presenting in the third trimester. Fortunately, this serious disorder is uncommon, with rates of approximately 1 in 10,000 pregnancies. In some cases of acute fatty liver, there is a recessively inherited mitochondrial abnormality of fatty acid oxidation, similar to those in children with Reye-like syndromes. Recurrence in subsequent pregnancies is uncommon but has been described, especially if the woman is carrying a homozygous enzyme-deficient fetus. The most common symptoms of acute fatty liver of pregnancy are persistent nausea and vomiting. Other symptoms include malaise, anorexia, abdominal pain, edema, and progressive jaundice. In the most severe cases, women may present with hepatic encephalopathy. Common laboratory abnormalities include modestly elevated serum aminotransferase levels, elevated bilirubin, raised prothrombin time, leukocytosis, elevated serum creatinine, decreased fibrinogen, and thrombocytopenia. In more severe cases, hypoglycemia, elevated serum ammonia levels, lactic acidosis, and disseminated intravascular coagulation may be present. Imaging of the liver by ultrasound or other modalities may or may not be useful. Liver biopsy is rarely necessary to make the diagnosis but would show characteristic microvesicular steatosis and canalicular cholestasis. In about half of affected women, some combination of hypertension, proteinuria, and edema may be present, making it difficult to differentiate from severe preeclampsia. However, increased bilirubin, markedly decreased fibrinogen levels, and profound liver dysfunction are less common in preeclampsia. Viral serologies should be obtained to rule out viral hepatitis (see Chapter 24).
FIGURE 21.2. Pharmacologic management of nausea and vomiting of pregnancy (NVP). American College of Obstetricians and Gynecologists. Nausea and Vomiting of Pregnancy. ACOG Practice Bulletin No. 52. Washington, DC: American College of Obstetricians and Gynecologists; 2004;103:803–815 (Reaffirmed 2011). Association of Professors of Gynecology and Obstetrics (APGO) Educational Series on Women’s Health, “Nausea and Vomiting of Pregnancy,” 2011.
Management
Intensive supportive care and prompt delivery are key to optimal management. In the past, maternal mortality approached 75% and perinatal mortality 90%. More recent literature reports maternal mortality rates of 7% and perinatal mortality 15%. Delivery typically stops further decline in liver function, but recovery may be prolonged. Infants should be assessed for signs associated with defects in fatty acid oxidation.
Preeclampsia and HELLP Syndrome
Hypertensive disorders in pregnancy that affect the liver include severe preeclampsia–eclampsia syndromes and HELLP. These disorders and their effects on the liver are discussed extensively in Chapter 22.
URINARY TRACT DISORDERS
Urinary tract infections (UTIs) are common in pregnancy. Approximately 8% of all women (pregnant and nonpregnant) have >105 colonies of a single bacterial species on a midstream culture. Approximately 25% of the pregnant women in this group develop an acute, symptomatic UTI. Other urinary tract disorders that may complicate pregnancy include urinary calculi, nephrolithiasis, and preexisting renal disease.
Asymptomatic Bacteriuria and Uncomplicated Urinary Tract Infection
Compared with nonpregnant women with similar colony counts on urine culture, asymptomatic bacteriuria in pregnancy is more likely to lead to cystitis and pyelonephritis. The increased incidence of symptomatic infection during pregnancy is thought to be caused by pregnancy-associated urinary stasis and glucosuria. This relative urinary stasis in pregnancy is a result of progesterone-induced decreased ureteral tone and motility, mechanical compression of the ureters at the pelvic brim, and compression of the bladder and ureteral orifices. In addition, the pH of urine is increased because of increased bicarbonate excretion, which also enhances bacterial growth.
A urine culture is obtained at the onset of prenatal care, and patients with asymptomatic bacteriuria are treated with ampicillin, cephalexin or nitrofurantoin. Empiric treatment with a 3-day course of antibiotics is 90% effective. Alternatively, a standard 7- to 10-day course may be considered. The most common organism identified is Escherichia coli. Approximately 25% to 30% of patients not treated for asymptomatic bacteriuria proceed to symptomatic UTI; hence, this treatment should prevent a significant number of symptomatic UTIs in pregnancy. However, 1.5% of patients with initial negative cultures also develop symptomatic UTIs during pregnancy. Also, recurrence rates for asymptomatic bacteriuria approach 30% even with effective therapy. Suppressive antimicrobial therapy is indicated if there are repetitive UTIs during pregnancy or following pyelonephritis during pregnancy. Consideration should be given to postpartum radiographic evaluation of these patients to identify renal parenchymal and urinarycollecting duct abnormalities.
Acute cystitis occurs in approximately 1% of pregnancies and can manifest with dysuria, urinary frequency, and urgency. The treatment is the same as for asymptomatic bacteriuria.
Pyelonephritis
Patients with pyelonephritis (inflammation of the renal parenchyma, calices, and pelvis) are acutely ill, with fever; costovertebral tenderness; general malaise; and, often, dehydration. Approximately 20% of these ill patients demonstrate increased uterine activity and preterm labor, and approximately 10% have positive blood cultures if they are obtained in the acute febrile phase of the disease. Pyelonephritis occurs in 2% of all pregnant patients and is one of the most common medical complications of pregnancy requiring hospitalization, especially in its context as a major cause of maternal mortality (septic shock).
Treatment
After urinalysis and urine culture are obtained, patients are treated with intravenous hydration and antibiotics, commonly a cephalosporin or ampicillin and gentamicin. Uterine contractions may accompany these symptoms, and specific tocolytic therapy may be considered depending on the patient’s status if preterm labor ensues. It is known that E. coli can produce phospholipase A, which, in turn, can promote prostaglandin synthesis, resulting in an increase in uterine activity. Fever is also known to induce contractions, so antipyretics are required for a temperature >100.4°F. Attention must be paid to the patient’s response to therapy and her general condition; sepsis occurs in 2% to 3% of patients with pyelonephritis, and adult respiratory distress syndrome can occur. If improvement does not occur within 48 to 72 hours, urinary tract obstruction, urinary calculus, or renal abscess should be considered, along with a reevaluation of antibiotic coverage. Ultrasonography or other imaging study such as computed tomography will sometimes identify a calculus or abscess. The organisms most commonly cultured from the urine of symptomatic pregnant patients are E. coli and other gram-negative aerobes. Follow-up can be with either frequent urine cultures and/or empiric antibiotic suppression with an agent such as nitrofurantoin.
Recurrent symptoms or failure to respond to usual therapy suggests another cause for the findings. In these patients, a complete urologic evaluation 6 weeks after pregnancy may be warranted.
Nephrolithiasis and Urinary Calculi
Urinary calculi are identified in approximately 1 in 1,500 patients during pregnancy, although pregnancy per se does not promote stone development. Symptoms similar to those of pyelonephritis but without fever suggest urinary calculi. Microhematuria is more common with this condition than in uncomplicated UTI. Renal colic (pain) is a typical symptom in nonpregnant women but is seen less frequently in pregnant women because of the hormone-induced relaxation of ureteral tone. Usually, hydration and expectant management, along with straining of urine in search of stones, suffice as management. Occasionally, however, the presence of a stone can lead to infection or complete obstruction, which may require urology consultation and drainage by either ureteral stent or percutaneous nephrostomy.
Preexisting Renal Disease
During preconception counseling, patients who have preexisting renal disease (chronic renal failure or transplant) should be advised of the significant risks involved in a pregnancy. Pregnancy outcome is related to the degree of serum creatinine elevation and the presence of hypertension.
Overall, pregnancy does not seem to have a negative impact on mild chronic renal diseases. In general, patients with mild renal impairment (serum creatinine <1.5 mg/dL) have relatively uneventful pregnancies, provided other complications are absent. Patients with moderate renal impairment (serum creatinine 1.5–3.0 mg/dL) have a more guarded prognosis with an increased incidence of deterioration of renal function. Patients with severe renal impairment have the worst outcome. In approximately 50% of patients with renal disease, proteinuria is noted. An increase in proteinuria during pregnancy is not, by itself, a serious consequence. Many patients with renal disease also have preexisting or concurrent hypertension. These women are at increased risk for hypertensive complications of pregnancy.
In addition to hypertension, there is an increased incidence of intrauterine growth restriction in patients with chronic renal disease. Serial assessments of fetal well-being and growth are frequently performed. Pregnancy following renal transplantation is generally associated with a good prognosis if at least 2 years have elapsed since the transplant was performed and thorough renal assessment reveals no evidence of active disease or rejection. Drug therapy should be minimal.
SURGICAL CONDITIONS
Patients who are pregnant can experience the same surgical conditions as those who are not pregnant, such as appendicitis, cholelithiasis, and bowel injury. In early gestation, ectopic pregnancy and torsion of the adnexa should be considered. Later in pregnancy, placental abruption and uterine rupture can cause acute abdominal signs and symptoms (see Section “Trauma in Pregnancy”).
Considerations for Pregnant Patients
Surgical treatment of a pregnant woman should take into consideration both maternal and fetal health needs. Radiographic or other studies should not be avoided just because the patient is pregnant, though precautions should be used. For procedures such as radiographs of the chest, an abdominal shield may be used to avoid unnecessary exposure to the fetus. Exposure to low doses of radiation is safe for the fetus when considered against failure to treat or to diagnose a condition requiring surgery. In the perioperative period, fetal heart tones should be monitored to the extent possible, consistent with the stage of gestation and need for intervention, usually by electronic fetal monitoring.
The completely supine position should be avoided, if possible. Instead the patient should be placed in a decubitus lateral tilt to prevent supine hypotensive syndrome, in which pressure on the vena cava reduces venous return to the heart, causing a drop in blood pressure and uterine blood flow. Oxygen administration may be helpful. In general, clinicians caring for these patients should be constantly aware of both maternal and fetal considerations. For example, the residual lung volume is diminished in pregnancy, which provides less reserve for respiratory function. Delayed gastric emptying makes aspiration of stomach contents during a surgical procedure more likely.
Cholelithiasis in Pregnancy
Reproductive-aged women frequently have gallstones. Cholelithiasis can be exacerbated during pregnancy due to hormonal effects that slow gallbladder emptying and cause an increase in residual gallbladder volume.Asymptomatic cholelithiasis should be managed expectantly. If the patient develops biliary colic, attempts should be made to conservatively treat the patient with hydration, pain control, dietary restriction, and possible nasogastric tube. However, if cholecystitis occurs with common bile duct obstruction, ascending cholangitis, pancreatitis, or acute abdomen, immediate surgical management is required. Maternal and fetal outcomes tend to be excellent if surgical removal is undertaken before these serious consequences are allowed to worsen. As with appendicitis, traditional surgical management has been open cholecystectomy; however, in recent years, more evidence supports the safe use of laparoscopic cholecystectomy in pregnancy.
Appendicitis in Pregnancy
Appendicitis is a common surgical problem in reproductive-aged women, and, therefore, a common surgical problem in pregnancy. Similar symptoms of the disease occur in pregnancy; of note, leukocytosis associated with appendicitis may be masked with the normal leukocytosis of pregnancy. The appendix may be displaced upward as pregnancy advances and can cause a shift in the location of abdominal pain associated with appendicitis, though pain is still most commonly located in the right lower quadrant. When appendicitis is diagnosed and treated early (before appendiceal rupture and generalized peritonitis), fetal and maternal outcomes are good. Surgical management has traditionally been with open appendectomy; however, laparoscopy is increasingly being utilized for the management of appendicitis in pregnancy.
Adnexal Masses in Pregnancy
Abnormal ovarian or adnexal masses can occur in pregnancy. Often, they are discovered during routine ultrasound examination of the fetus. Most of these masses are benign and spontaneously resolve during pregnancy. For these reasons, expectant management is often advocated for adnexal masses in pregnancy. Approximately 4% to 7% of persistent complex masses are malignant. With larger masses, there is an increased risk of ovarian torsion or cyst rupture. In general, surgical management is best performed in the second trimester.
TRAUMA IN PREGNANCY
Maternal trauma is one of the leading causes of morbidity and mortality in pregnancy. The most common cause of trauma in pregnancy is motor vehicle accidents. The second most common cause is physical violence against women, most frequently partner violence. Traumatic injury can result in maternal injury and death, as well as placental abruption, uterine rupture, fetal–maternal hemorrhage, premature rupture of membranes, or preterm labor. In addition to the above conditions, which can compromise fetal well-being, direct fetal injury is also possible.
Management
The primary goal for evaluation of a pregnant trauma patient is maternal stabilization. Management is essentially the same as for the nonpregnant patient. Vital signs should be assessed and the patient stabilized, followed by obstetric assessment. If the gestational age is 20 weeks or beyond, the patient should be placed in a decubitus lateral tilt position. If this is not feasible (e.g., due to cervical spine stabilization), tilting the backboard by placing a wedge underneath or manual displacement of the uterus off midline will promote adequate maternal venous return. Fetal assessment includes verification of fetal heart tones with Doppler, followed by electronic fetal monitoring once the secondary survey is complete. Fetal ultrasound is also helpful for identifying location of placenta, fetal well-being, amniotic fluid volume, and estimated gestational age.
After a minor trauma, electronic fetal monitoring (including tocometry) is recommended from 2 to 6 hours (however, there are no large studies available to guide a consensus on the appropriate length of time for monitoring to occur). If, during that interval, there are any signs of uterine tenderness, irritability or contractions, vaginal bleeding, rupture of membranes, or nonreassuring fetal status, continued monitoring for at least 24 hours is advocated. Any moderate or major trauma necessitates at least 24 hours of continuous fetal monitoring.
Fetal–Maternal Hemorrhage
Fetal–maternal hemorrhage is another complication of maternal trauma, and determination of Rh status is an important part of the management. The extent of fetal–maternal hemorrhage can be determined using one of several tests (e.g., the Kleihauer-Betke test). Most often, a regular dose of Rh immunoglobulin is protective for all Rh-negative mothers.
If a pregnant woman undergoes cardiopulmonary arrest, attempts at resuscitation should begin immediately. Emergent cesarean delivery should be considered after 4 minutes of failed resuscitation efforts if the patient is in the third trimester of pregnancy. Maternal resuscitation is made easier once the fetus has been delivered. Fetal survival is not likely if maternal vital signs have been absent for more than 10 to 15 minutes.
Clinical Follow-Up
You perform a careful history and physical examination; there are no symptoms other than the nausea and vomiting, no underlying medical disorders, and no abnormal physical findings (specifically, no goiter). An ultrasound shows a normal intrauterine pregnancy at 9 weeks of gestation. You draw some blood tests but reassure the patient that her nausea and vomiting are most likely related to the pregnancy and not hyperthyroidism. You recommend some dietary and lifestyle modifications as well as some medications for her symptoms. You reassure her that these medications will not harm her baby and may prevent her from missing work or having to come to the hospital with more severe vomiting. You plan to see her back to reassess her symptoms and review the blood tests.
thePoint Visit http://thepoint.lww.com/activate for an interactive USMLE-style question bank and more!