Fetal breathing movements as predictor of favourable pregnancy outcome after oligohydramnios due to membrane rupture in second trimester.

In 11 pregnancies complicated by oligohydramnios due to spontaneous rupture of the membranes in the second trimester of pregnancy fetal breathing movements were assessed regularly by ultrasonographic examinations. In the 6 cases in which fetal breathing movements were detected the babies were liveborn and there was no evidence of pulmonary hypoplasia or the other non-renal features of Potter's syndrome. In the other 5 cases there were no fetal breathing movements. 1 pregnancy was terminated electively, and 1 ended in an intrauterine death; the remaining 3 infants died in the neonatal period. All 5 cases showed necropsy evidence of pulmonary hypoplasia. These findings indicate that premature and prolonged rupture of membranes in the second trimester of pregnancy does not uniformly result in a poor prognosis. They suggest that fetal breathing movements could be used as a predictor of favourable neonatal outcome.