A 24-year-old G1P0 presents at 30 weeks’ gestation for a new OB visit. She provides you with the official report of a dating ultrasound performed at 12 weeks; however, shortly thereafter, she moved out of state and has not had prenatal care. She has no medical problems, and has a normal BMI. She reports some abdominal cramping and shortness of breath. During her visit, you examine her cervix and it is closed. You measure her fundal height at 50 cm.
An ultrasound is performed, and demonstrates a singleton fetus with an estimated fetal weight (EFW) in the 53 percentile. The amniotic fluid index is 30 cm, consistent with a diagnosis of polyhydramnios.
How should you counsel this patient?A. She does not require any further evaluation
Polyhydramnios is defined as an excessive quantity of amniotic fluid, and occurs in 1% to 2% of pregnant women. When diagnosed, it requires further evaluation for genetic or anatomic anomalies, diabetes, and infection, although approximately 40% of cases are determined to be idiopathic. The incidence of associated malformations is about 20%, with CNS and GI abnormalities being particularly common, due to their impact on swallowing and absorption of amniotic fluid. Polyhydramnios accompanies about half of cases of anencephaly, and nearly all cases of esophageal atresia. Edema of the lower extremities, vulva, and abdominal wall is common, and results from compression of major venous systems. The most frequent maternal complications are placental abruption, uterine dysfunction, and postpartum hemorrhage.