Plasma steroid changes in pre-term labour in association with salbutamol infusion.

Serial measurements of peripheral plasma concentrations of progesterone and oestradiol-17beta were made in 23 women with singleton pregnancies who were given intravenous salbutamol in an attempt to inhibit pre-term labour. Mean levels of both hormones fell significantly during salbutamol infusion but returned to pre-treatment levels after therapy was stopped. Plasma human placental lactogen concentrations did not change during salbutamol infusion, suggesting that the fall in steroid hormone levels was unlikely to be an effect of altered uterine or placental blood flow.