Plasma renin substrate in the prediction of pregnancy outcome in threatened abortion

Summary. Concentrations of plasma renin substrate, serum oestradiol-17β, human chorionic gonadotrophin, sex-hormone binding globulin and plasma renin activity were measured in 77 samples from 74 patients with uterine bleeding during the first and second trimesters of pregnancy and in a control group of 29 normal pregnant women (51 samples). Mean concentrations of these substances were lower than control values in patients with an abnormal outcome of pregnancy. In patients with a normal outcome after uterine bleeding, concentrations were mostly within the control range. Serum oestradiol-17β concentration was superior to the other variables in predicting fetal outcome in the whole group. In patients with a live fetus at the time of blood sampling but who subsequently aborted, serum oestradiol-17β concentration was mostly normal, whereas plasma renin substrate was decreased. Our results suggest that plasma renin substrate may provide additional prognostic information to that given by serum oestradiol-17β measurement or ultrasonography in threatened abortion.