Amniotic fluid endothelin levels and the incidence of premature rupture of membranes

Objective. The purpose of this prospective study was to record Endothelin 1 (ET1) concentrations in the second trimester amniotic fluid and in women who develop premature rupture of membranes (PROM), preterm premature rupture of the membranes (PPROM) and in women with uneventful pregnancies. Method. Amniotic fluid was retrieved by amniocentesis from 125 women in the second trimester of pregnancy. The levels of Endothelin were measured by a sensitive and specific radioimmunoassay. Results. From the 125 women included in the study 20 developed PROM and preterm PROM (13 PPROM and 7 PROM). The ET1 concentration was significantly higher ( P < 0.001) in PROM and PPROM than in normal pregnancy (96.4 vs. 43 pg/ml). The sub-analysis of the two rupture of membranes groups found that the concentration of ET1 was higher in the PPROM than in PROM (118 vs. 72 pg/ml). Conclusion. The amniotic fluid concentration of ET1 is elevated by the second trimester in women who later develop preterm PROM or term PROM.