First-trimester serum prolactin levels in normal and complicated pregnancies.

Subfractional activities and some properties of beta-glucuronidase were studied at different ontogenetic stages of the human placenta. Maximum activity was localized in normal pregnancies rose from 13.58 ng/ml in the 6th week to 52.46 ng/ml in the 15th week of gestation with marked individual variability. In tubal pregnancies, serum hPRL was low and did not increase over a period of 3--6 weeks. In women with spontaneous abortion, hPRL levels often were in the normal range with a drop only immediately prior to expulsion of the fetus. In patients with missed abortion the drop in serum prolactin levels seemed to coincide with the death of the conceptus.