Polyhydramnios is associated with multiple maternal and fetal abnormalities. Although the risks of persistent polyhydramnios are well described, the clinical implications of polyhydramnios that resolves prior to delivery are not. Thirty-four non-diabetic patients with resolving polyhydramnios were studied. An amniotic acid index of >or= 20 was used to define polyhydramnios. Antepartum and postpartum outcomes were compared with those patients with persistent polyhydramnios, and a control group of 102 singleton term deliveries. Patients with resolving polyhydramnios did not have a significant increase in congenital anomalies. An 8% incidence of congenital anomalies was noted in patients with persistent polyhydramnios; this was significant compared with controls (p < 0.05). Idiopathic resolving polyhydramnios was associated with a higher mean birth weight (p < 0.05) than controls, with significantly more babies weighing more than 4200 g. An increase in placental thrombus formation was noted in patients with idiopathic resolving and persistent polyhydramnios compared to the control group (p < 0.01). The etiology of this is unclear. Obstetricians should be aware of the risk of macrosomia and the possibility of placental disease in these fetuses.
Copyright 1992 International Society of Ultrasound in Obstetrics and Gynecology