Prostaglandin E2 release on the fetal and maternal sides of the amnion and chorion-decidua before and after term labor

Release of prostaglandin E2 on each of the fetal and maternal sides of the fetal membranes (8 cm2) from term cesarean (no labor) and spontaneous vaginal (labor) deliveries was studied with the use of dual-compartment perfusion chambers. Postlabor amnion released significantly (p < 0.05) more total prostaglandin E2 (5.66 ± 1.02 ng, mean ± SEM) than prelabor tissue (3.34 ± 1.76 ng) with equivalent prostaglandin E2 levels being released on both sides. A net decrease (p < 0.001) in prostaglandin E2 release by chorion-decidua was identified after labor (fetal = 0.12 ± 0.05 ng; maternal = 0.17 ± 0.09 ng) when compared with that before labor (fetal = 1.28 ± 0.69 ng; maternal = 2.31 ± 0.56 ng). Amnion-chorion-decidua released more prostaglandin E2 on the fetal side after labor (2.37 ± 1.43 ng) than prior to labor (1.49 ± 0.60 ng); however, prostaglandin E2 on the maternal side was significantly less (p < 0.05) after labor (0.24 ± 0.12 ng) when compared with that of the prelabor membrane (2.03 ± 1.08 ng). Elution of prostaglandin E2 from preincubated membranes and endogenous membrane prostaglandin E2 content showed similar results. Thus concentrations of prostaglandin E2 on the maternal side of the fetal membranes appear diminished after spontaneous labor despite an increased release from the fetal surface.