Introduction Description: Polyhydramnios (also known as hydramnios) is an abnormal increase in the amount of amniotic fluid surrounding the fetus. This diagnosis is generally reserved for volumes greater than 2 L and amniotic fluid index greater than 24–25 cm. (At term, there should be approximately 800 mL of amniotic fluid present). This fluid may gradually accumulate over time (chronic hydramnios) or acutely over the course of…

Introduction Description: Placental abruption is the premature separation of an otherwise normally implanted placenta before the delivery of the fetus. The term is generally applied only to 20-week or later gestations. Prevalence: 1/185–290 deliveries; sufficient to result in fetal death, 2–10/1000 deliveries (approximately 10% of third-trimester fetal demise). Predominant Age: Reproductive age. Genetics: No genetic pattern. Etiology and Pathogenesis Causes: Pregnancy-induced hypertension (most common), trauma to…

Introduction Description: Placenta previa is the implantation of the placenta in a location that leaves a part or all of the cervical os covered. This is associated with potentially catastrophic maternal bleeding and obstruction of the uterine outlet. Several degrees are recognized: total, partial, marginal, and low-lying placenta. These degrees may vary with cervical dilation or gestational age. Prevalence: Observed in 0.3%–0.5% of deliveries; up to…

Introduction Description: Oligohydramnios is an abnormal reduction in the amount of amniotic fluid surrounding the fetus. At term, there should be approximately 800 mL of amniotic fluid present. Often defined as a single deepest pocket of amniotic fluid of 2 cm or less or an amniotic fluid index (sum of maximum vertical fluid pocket in each quadrant not containing umbilical cord or fetal extremities) of 5…

Introduction Description: Obstetric lacerations of the vaginal wall or introitus are common in vaginal deliveries. Laceration of the cervix, labia, and periurethral and periclitoral (prepuce) tissues is also possible. Prevalence: Common; 50%–80% of vaginal deliveries; third- and fourth-degree lacerations occur in less than 5% of deliveries. Predominant Age: Reproductive age (most common in females younger than 25 years). Genetics: No genetic pattern. Etiology and Pathogenesis Causes:…

Introduction Description: Multiple gestation is two or more fetuses that coexist during the same gestation. Prevalence: Occurs in 32.1/1000 live births resulting in 112,437 births in the United States (2020); 79.6/100,000 live births for triplets, for a total of 2738 births in the United States and 137 quadruplet or higher births. The rate of multiple births is influenced by the use of fertility drugs and the…

Introduction Description: Intrauterine growth restriction is the symmetric or asymmetric reduction in the size and weight of the growing fetus in utero compared with that expected for a fetus of comparable gestational age and population. (Low birthweight is used to describe newborns who weigh less than the 10th percentile.) Growth restriction may occur for many reasons, but most occurrences represent signs of significant risk for fetal…

Introduction Description: Hyperemesis gravidarum is exaggerated nausea and vomiting during early pregnancy, which is sufficient to produce dehydration, metabolic disturbances, and weight loss. Alkalosis (from HCl loss) and hypokalemia are common. Prevalence: 70%–85% of women experience nausea; 50% have emesis in the first trimester; hyperemesis occurs in 0.5%–2% of pregnancies. Predominant Age: Reproductive age. Genetics: No genetic pattern. Etiology and Pathogenesis Causes: Unknown. Most closely associated…

Introduction Description: Hepatitis is one of the most serious infections that occur during pregnancy. Prevalence: Hepatitis—0.1%–1.5% of pregnancies (one-third of Americans have antibodies to hepatitis A). Hepatitis B is the most common cause of jaundice during pregnancy. The prevalence of hepatitis in pregnancy has declined in the past 15 years. Predominant Age: Reproductive age. Genetics: No genetic pattern. Etiology and Pathogenesis Causes: Six or more different…

Introduction Description: Hemolysis, elevated liver enzymes, low platelet count (HELLP) syndrome is considered to be a variant of pregnancy-induced hypertension (PIH) and pre-eclampsia, which are dominated by hepatic and hematologic changes. The course of HELLP syndrome is notable for its progressive and sometimes sudden deterioration in maternal and fetal condition. Prevalence: 0.1%–1% of pregnancies; up to 20% of patients with severe pre-eclampsia. Most cases occur during…

Introduction Description: Elevated hormone levels during pregnancy may induce gingival hyperplasia, pedunculated gingival growths, and pyogenic granuloma. Despite concerns directed elsewhere during pregnancy, the practitioner must watch for this common problem and address it when present. Periodontal disease has been identified as a risk factor for preterm delivery. Prevalence: Common (some estimate up to 90% of population affected). Pregnancy-associated pyogenic granuloma occurs in approximately 0.5%–5% of…

Introduction Description: Gestational trophoblastic diseases include choriocarcinoma, molar pregnancy (hydatidiform mole and invasive mole), placental-site trophoblastic tumor, and epithelioid trophoblastic tumor (rare variant of placental-site tumors). They are abnormalities of pregnancy that arise entirely from abnormal placental proliferation. They are classified as being either complete, in which no fetus is present, or incomplete (partial), in which both fetus (generally abnormal) and molar tissues are present. Prevalence:…

Introduction Description: Fetal alcohol spectrum syndrome is characterized by malformations found in infants born to mothers who have consumed alcohol during pregnancy. Abnormalities include structural malformations (predominantly facial), growth restriction, and neurologic abnormalities, including mental retardation. Prevalence: Estimates vary from 6/10,000 births to 2/1000 births and globally as high as 23/1000 births. US rates are estimated to be 1%–5% of births. Intrauterine exposure to alcohol is…

The Challenge The challenge is to diagnose and manage disturbances of glucose metabolism to minimize the risk associated with diabetes in mothers and fetuses. Diabetes and pregnancy have profound effects on each other, making a familiarity with the interactions between mother, fetus, and the diabetic process a requirement to provide optimal care. Scope of the Problem: Diabetes mellitus is the most common medical complication of pregnancy,…

Introduction Description: Chorioamnionitis is the inflammation of the fetal membranes. This may be associated with prolonged or premature rupture of the membranes or a primary cause of premature labor. A Eunice Kennedy Shriver National Institute of Child Health and Human Development expert panel proposed a descriptive term: “intrauterine inflammation or infection or both” abbreviated as “Triple I” to replace the term chorioamnionitis. The same panel recommended…

Introduction Description: Cholelithiasis and cholecystitis complicate more than 3% of pregnancies. Acute cholecystitis is the second most common nonobstetric indication for surgery during pregnancy (after acute appendicitis). Prevalence: Cholelithiasis—3%–4% of pregnancies; cholecystitis—0.25% of pregnancies. Predominant Age: Reproductive age. Genetics: Some groups are at greater risk (eg, Pima Indians). Etiology and Pathogenesis Causes: The metabolic alteration leading to cholesterol stones (gallstones) is considered to be a disruption…

Introduction Description: Cervical insufficiency is characterized by the asymptomatic dilation of the internal os during pregnancy. This generally leads to the dilation of the entire cervical canal during the second trimester with the subsequent risk for rupture of the membranes, expulsion of the fetus, or both. Most often, this occurs before 24 weeks gestation. Prevalence: 1/54 to 1/1842 pregnancies (as a result of uncertain diagnostic criteria);…

The Challenge Cardiac disease is one of the major causes of nonobstetric maternal mortality. Whereas in the past patients with congenital or significant heart disease did not survive to the reproductive age, it is now common for these patients to become pregnant, be it planned or unplanned. Cardiovascular disease in pregnancy is often underdiagnosed, resulting in unnecessary morbidity or mortality (possibly as much as 2-fold higher).…

Introduction Description: Caput succedaneum is a characteristic change in the apparent shape of the fetal head and scalp that results from the forces of labor acting on the fetal head and the surrounding tissues. This swelling is generally located on the portion of the fetal scalp that is directly under the cervical os. Prevalence: Typical of most vaginal vertex births. Similar swellings on the presenting part…

Introduction Description: Breech birth is the presentation of the fetal buttocks (frank breech; 50%–70%), one foot, or both feet at the cervix (complete breech with hips flexed, 5%–10%; incomplete breech with the hips extended, 10%–40%) at the time of labor. Prevalence: The rate of breech deliveries decreases with advancing gestational age from 22%–25% of births less than 28 weeks, to 7%–15% of births at 32 weeks,…