Prostaglandin F2α output by amnion-chorion-decidua: Relationship with labor and prostaglandin E2 concentration at the amniotic surface

OBJECTIVE: Our purpose was to evaluate prostaglandin F2α output at fetal membrane surfaces relative to labor and to assess amniotic prostaglandin E2 concentration changes on prostaglandin F2α output. STUDY DESIGN: Intact and separated fetal membranes from 10 elective cesarean sections and nine vaginal deliveries were incubated in double-sided perfusion chambers. Prostaglandin F2α and 13,14-dihydro-15-keto-prostaglandin F2α output was measured by radioimmunossay. Alterations of prostaglandin F2α and 13,14-dihydro-15-keto-prostaglandin F2α output were assessed after exogenous prostaglandin E2 addition at amniotic surfaces of intact membranes. RESULTS: Prostaglandin F2α concentration was higher at maternal surfaces of intact but not separated membranes after labor (p = 0.0001). Amniotic 13,14-dihydro-15-keto-prostaglandin F2α was increased in association with preceding labor (p = 0.038). Addition of prostaglandin E2 at the amniotic surface did not alter prostaglandin F2α or 13,14-dihydro-15-keto-prostaglandin F2α production. CONCLUSION: Prostaglandin F2α concentration at the maternal surface of fetal membranes likely plays a critical role in induction or maintenance of myometrial contractions associated with term labor independent of amniotic fluid prostaglandin E2 concentrations.