Objective: Our purpose was to evaluate prostaglandin F2 alpha output at fetal membrane surfaces relative to labor and to assess amniotic prostaglandin E2 concentration changes on prostaglandin F2 alpha 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 F2 alpha and 13,14-dihydro-15-keto-prostaglandin F2 alpha output was measured by radioimmunoassay. Alterations of prostaglandin F2 alpha and 13,14-dihydro-15-keto-prostaglandin F2 alpha output were assessed after exogenous prostaglandin E2 addition at amniotic surfaces of intact membranes.
Results: Prostaglandin F2 alpha concentration was higher at maternal surfaces of intact but not separated membranes after labor (p = 0.0001). Amniotic 13,14-dihydro-15-keto-prostaglandin F2 alpha was increased in association with preceding labor (p = 0.038). Addition of prostaglandin E2 at the amniotic surface did not alter prostaglandin F2 alpha or 13,14-dihydro-15-keto-prostaglandin F2 alpha production.
Conclusion: Prostaglandin F2 alpha 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.