Amniotic fluid prostaglandin F2 increases even in sterile amniotic fluid and is an independent predictor of impending delivery in preterm premature rupture of membranes.

OBJECTIVE: To determine whether amniotic fluid (AF) concentration of prostaglandins (PGs) increases in patients with intra-amniotic inflammation and/or proven AF infection in preterm PROM, and can predict impending delivery.
METHODS: AF PGF2a concentrations were determined by ELISA in 140 singleton pregnancies with preterm premature rupture of membranes (PROM) (< or =35 weeks). AF was cultured for aerobic and anaerobic bacteria, and genital mycoplasmas. Intra-amniotic inflammation was defined as an elevated AF matrix metalloproteinase-8 concentration (>23 ng/ml). Results. (1) Patients with intra-amniotic inflammation and a negative AF culture had a significantly higher median AF PGF2a than those without intra-amniotic inflammation and with a negative culture (p < 0.001); (2) However, there was no difference in the median AF PGF2a between patients with intra-amniotic inflammation with a negative culture and those with culture-proven AF infection (p > 0.1); (3) Patients with an elevated AF PGF2a had a significantly shorter interval-to-delivery than those with a low AF PGF2a (< or =170 pg/mL) (p < 0.001); (4) An elevated AF PGF2a (< or =170 pg/mL) concentration was a significant predictor of the duration of pregnancy after adjusting for gestational age and AF inflammation/infection (p < 0.005). Conclusions. AF PGF2a (> or =170 pg/mL) concentration increased in patients with intra-amniotic inflammation regardless of AF culture results. Moreover, an elevated AF PGF2a concentration was an independent predictor of impending delivery in preterm PROM.