Plasma progesterone, dehydroepiandrosterone sulfate and estriol levels during labor induction with a sustained-release prostaglandin E2 vaginal insert.

OBJECTIVE: To measure plasma progesterone, dehydroepiandrosterone sulfate (DHEAS) and estriol levels in women induced for labor with a sustained-release vaginal polymer prostaglandin E2 insert, and to analyze the relationships between the changes in hormone levels and Bishop score. METHODS: Twelve primipara and 12 multipara were treated with a sustained-release polymer vaginal prostaglandin E2 insert (0.3 mg/h) for up to 24 h. The Bishop score was assessed at the start and end of therapy, and serum samples were collected at 4-h intervals. Plasma levels of progesterone, DHEAS and estriol were measured by specific radioimmunoassays. RESULTS: Exposure averaged 13.5 +/- 7.2 h. Progesterone levels decreased in the majority of patients (79.2%) after the start of therapy. Higher baseline DHEAS and estriol levels were observed among women who achieved an improvement in Bishop score of at least 4 during prostaglandin E2 treatment. CONCLUSIONS: Higher DHEAS and estriol levels prior to labor induction with prostaglandin E2 may be indicators of a favorable labor outcome. Additional studies are needed to substantiate the decrease in progesterone levels observed in this study and the importance of this phenomenon for the mechanism of labor induction with prostaglandin E2.