Idiopathic polyhydramnios and perinatal outcome

The aim of this study was to determine whether there is any association between idiopathic polyhydramnios and adverse perinatal outcome.

One hundred fifty-one consecutive women with singleton pregnancies complicated by idiopathic polyhydramnios (amniotic fluid index >24 cm) who were delivered at our institution during an 18-month period (December 1996-May 1998) were studied. Outcome measures studied included preterm delivery (<37 weeks' gestation), low birth weight (<2500 g), macrosomia (>4000 g), malpresentation at delivery, rate of cesarean delivery, Apgar score at 5 minutes <7, admission to the neonatal intensive care unit, and perinatal death. These findings were compared by means of the chi(2) test with those of 302 matched control subjects with normal amniotic fluid volume (<24 cm).

Among pregnancies complicated by idiopathic polyhydramnios we did not observe any increases in preterm deliveries, low birth weight, low Apgar scores at 5 minutes, neonatal intensive care unit admissions, or perinatal mortality rate. However, idiopathic polyhydramnios was associated with significantly higher rates of malpresentation, macrosomia, and primary cesarean delivery.

In contrast to previous reports that polyhydramnios related to specific causes (congenital anomalies, diabetes mellitus, isoimmunization) is associated with adverse perinatal outcomes, such as prematurity, low birth weight, and perinatal death, idiopathic polyhydramnios is not associated with higher rates of these traditional measures of poor outcome.