Changes in Unconjugated Oestrogens and Progesterone Concentration in Plasma at the Approach of Labour

Summary The concentrations of unconjugated oestriol, of unconjugated oestradiol and of progesterone were measured in the plasma of ten normal pregnant women during the last 15 to 21 days of pregnancy and in labour. The approach of labour was not associated with any consistent change in hormone concentration or in the relationship of oestrogen and progesterone levels to one another.