Endocrinology of normal pregnancy and premature labour.

Peripheral plasma levels of the biologically important hormones of pregnancy--plasma oestradiol 17 beta, plasma oestriol, plasma progesterone, human placental lactogen (hPL) and human chorionic gonadotrophin (hCG) have been measured serially in a control group of 10 normal women who delivered at term +/- three days. A second group of patients were similarly studied when admitted in premature labour and the levels compared with the control group. The levels of all hormones except human chorionic gonadotrophin increased till 37 weeks. After the 30th week, the increase of oestriol was steeper than oestradiol and hPL. The hormone profile of the maternal plasma is a good index of feto-placental function. The hPL levels which heralded the increase in endocrine function of the feto-placental unit were also elevated in premature labour, suggesting a casual relationship of significance. Levels of plasma oestradiol in premature labour were considerably higher than in the control study and suggests an endocrine basis for premature labour of hitherto unknown aetiology.