Fetal breathing movements and prostaglandin levels in pregnancies complicated by premature rupture of the membranes.

Abstract

We have previously demonstrated that maternal and fetal prostaglandin levels may be elevated in patients with pregnancies complicated by premature and prolonged rupture of the membranes (PPROM) compared to patients with intact membranes. In the fetal lamb, infusion of prostaglandin abolishes fetal breathing movements and in human pregnancies with PPROM and with poor outcome, fetal breathing movements are absent. The aim of this study was to determine fetal breathing activity in pregnancies complicated by PPROM which had elevated prostaglandin levels. One-hour ultrasound examinations were performed on nine fetuses whose mothers had had premature rupture of the membranes at 28 weeks gestation and a median of 4 days prior to the ultrasound examination. The number of fetal breathing movements (FBM) and percentage of time that each fetus spent breathing was documented and this was then related to control values. Following the completion of the ultrasound examination, cordocentesis was performed and blood sent for estimation of bicyclo PGEM levels. All of the fetuses made some breathing activity during the one-hour period, but the number of FBM varied from 1 to 181 (median 21). The percentage time that the fetuses spent breathing was much lower than that which would be expected for their gestational age, being a median of 1.3% (range less than 0.1 to 50.8%) of control values. As bicyclo PGEM levels were elevated in these nine fetuses, these data suggest that reduction in breathing activity in fetuses of pregnancies complicated by PPROM may be due to elevated prostaglandin levels.