Sex steroid hormone concentrations in preterm labour and the outcome of treatment with ritodrine

Peripheral plasma concentrations of unconjugated oestradiol‐17β, progesterone and total oestriol were measured in patients presenting with uncomplicated preterm labour. Control samples were obtained from normal healthy women matched for maternal age, parity and duration of pregnancy. Oestrogen concentrations were often higher and progesterone concentrations often lower in patients presenting in preterm labour, and in particular, in those presenting in advanced labour and those failing to respond to treatment with ritodrine, but the differences were not statistically significant.