SMFM Consult Series #46: Evaluation and management of polyhydramnios

Abstract

Polyhydramnios, or hydramnios, is an abnormal increase in the volume of amniotic fluid. Identification of polyhydramnios should prompt a search for an underlying etiology. Although most cases of mild polyhydramnios are idiopathic, the 2 most common pathologic causes are maternal diabetes mellitus and fetal anomalies, some of which are associated with genetic syndromes. Other causes of polyhydramnios include congenital infection and alloimmunization. The purpose of this document is to provide guidance on the evaluation and management of polyhydramnios. The following are Society for Maternal-Fetal Medicine recommendations: (1) we suggest that polyhydramnios in singleton pregnancies be defined as either a deepest vertical pocket of ≥8 cm or an amniotic fluid index of ≥24 cm (GRADE 2C); (2) we recommend that amnioreduction be considered only for the indication of severe maternal discomfort, dyspnea, or both in the setting of severe polyhydramnios (GRADE 1C); (3) we recommend that indomethacin should not be used for the sole purpose of decreasing amniotic fluid in the setting of polyhydramnios (GRADE 1B); (4) we suggest that antenatal fetal surveillance is not required for the sole indication of mild idiopathic polyhydramnios (GRADE 2C); (5) we recommend that labor should be allowed to occur spontaneously at term for women with mild idiopathic polyhydramnios; that induction, if planned, should not occur at <39 weeks of gestation in the absence of other indications; and that mode of delivery should be determined based on usual obstetric indications (GRADE 1C); and (6) we recommend that women with severe polyhydramnios deliver at a tertiary center due to the significant possibility that fetal anomalies may be present (GRADE 1C).

Educational Case: Intrauterine Fetal Demise and Intestinal Atresia: An Autopsy Investigation

“…Furthermore, studies have shown that the severity of polyhydramnios directly correlates with the risk of prenatal abnormality as well as antepartum complications, such as the increased risk for premature delivery. 4 Considering these findings, intramuscular corticosteroid administration is given in anticipation of a possible preterm delivery.…”

Preoperative Cervical Length Predicts the Risk of Delivery within One Week after Pleuroamniotic Shunt in Fetuses with Severe Hydrothorax

“…Hydrops was defined as pleural effusion associated with either subcutaneous edema, ascites, or pericardial effusion [10]. Polyhydramnios was defined as increased amniotic fluid volume with a deepest vertical pocket above 8.0 cm or an amniotic fluid index above 24 cm, while moderate and severe polyhydramnios were defined as an amniotic fluid index above 30 and 35 cm, respectively [11]. Exclusion criteria were (a) preterm prelabor rupture of membranes (PPROMs), (b) chromosomal abnormalities, (c) other concomitant structural anomalies, and (d) placenta previa.…”

AIUM Practice Parameter for the Performance of Detailed Second‐ and Third‐Trimester Diagnostic Obstetric Ultrasound Examinations

“…Indications for a detailed fetal anatomic examination include, but are not limited to, the following conditions: Previous fetus or child with a congenital, genetic, or chromosomal abnormality; Known or suspected fetal anomaly or known or suspected fetal growth restriction in the current pregnancy; Fetus at increased risk for a congenital anomaly, such as the following: Maternal pregestational diabetes or gestational diabetes diagnosed before 24 weeks’ gestation; Pregnancy conceived via assisted reproductive technology; Maternal body mass index of 30 kg/m 2 or higher; Multiple gestations; Abnormal maternal serum analytes; Teratogen exposure; First‐trimester nuchal translucency measurement of 3.0 mm or greater; Fetus at increased risk for a genetic or chromosomal abnormality, such as the following: Parental carrier of a chromosomal or genetic abnormality; Maternal age of 35 years or older at delivery; Positive screening test results for aneuploidy; Aneuploidy marker noted on an ultrasound examination; First‐trimester nuchal translucency measurement of 3.0 mm or greater; Other conditions affecting the fetus, including the following: Congenital infections; Maternal drug use; Alloimmunization; Oligohydramnios; Polyhydramnios; and Suspected placenta PAS or risk factors for PAS such as placenta previa in the third trimester or a placenta overlying a prior cesarean scar site …”