The relation between plasma oestrogen, progesterone and prolactin concentrations and the efficacy of vaginal prostaglandin E2 gel in initiating labour.

In an attempt to relate the efficacy of treatment to endogenous hormone levels, plasma oestrogen, progesterone and prolactin levels were analysed in women at term following the vaginal administration of prostaglandin E2 gel to induce labour. Patients who went into labour after treatment had significantly higher oestradiol-17 beta levels before treatment compared with those requiring formal surgical induction the following day. No difference could be demonstrated in levels of progesterone or prolactin in the two groups of patients. The significance of these results is discussed.