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) (<= 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 (<= 170 pg/mL) (p<0.001); (4) An elevated AF PGF2a (<= 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 (>= 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.