Am J Obstet Gynecol. 1985 Feb 15;151(4):519-23.

Changes in the synthesis and metabolism of prostaglandins by human fetal membranes and decidua at labor.
Skinner KA, Challis JR.

The production of prostaglandins by dispersed cells from human amnion, chorion, and decidua was examined at term before the onset of labor and at spontaneous vaginal delivery. In order to obtain detailed information about relative prostaglandin production rates, the time course of prostaglandin output was examined by incubating the cells for up to 4 hours and measuring the cumulative output of prostaglandin E2, prostaglandin F2 alpha and 13,14-dihydro-15-keto-prostaglandin F2 alpha in the incubation media. The output of all three prostaglandins was low in tissues obtained before the onset of labor. At labor there was an increased production of prostaglandins E2 and F2 alpha in amnion and a small increase in the output of prostaglandin E2, prostaglandin F2 alpha, and 13,14-dihydro-15-keto-prostaglandin F2 alpha in decidua. In contrast, chorionic cells obtained at spontaneous vaginal delivery showed high levels of 13,14-dihydro-15-keto-prostaglandin F2 alpha in the media with no net production of prostaglandin E2 or F2 alpha. These data suggest a high rate of specific in vitro prostaglandin synthesis in amnion and decidua at labor, accompanied by a high rate of prostaglandin metabolism in chorion.