Effects of prostaglandin F2 alpha or oxytocin on serum estriol and its conjugates during induced labor.

Twelve patients underwent induction of labor at term, seven by prostaglandin F2 alpha (PGF) and five by oxytocin infusion. Serum samples were drawn before induction and at two hour intervals after infusion was started, throughout labor. The samples were analyzed for estriol (E3) and its principal conjugates, estriol-3-sulfate (E3-3S), estriol-16-glucosiduronate (E3-16G), estriol-3-glucosiduronate (E3-3G), and estriol-3-sulfate-16-glucosiduronate (E3-SG). No significant changes occurred before eight hours of infusion. Two pre-eclamptic patients showed a 100% increase in serum E3 while receiving PGF. The increases correlated best with rising levels of E3-SG. None of the five pre-eclamptic patients given oxytocin showed this striking changes. These observations raise the possibility that PGF may alter the metabolism of estriol in pre-eclamptic patients, during labor.