Serum oestradiol and progesterone concentrations during prolonged coasting in 15 women at risk of ovarian hyperstimulation syndrome following ovarian stimulation for assisted reproduction treatment.

Serum oestradiol and progesterone concentrations were examined for up to 7 days after withholding gonadotrophins whilst continuing pituitary down-regulation in 15 women at serious risk of severe ovarian hyperstimulation syndrome (OHSS) (serum oestradiol >6000 pg/ml and >15 follicles per ovary). Serum oestradiol concentrations rose on day 1 of coasting in all but two of the 15 women before falling, the decrement being in the order of 40% on each day. This observation permits a rational basis for the estimation of frequency of serum oestradiol measurements and duration of coasting. The trends and rates of fall of serum oestradiol do not seem to predict the occurrence of moderate and severe OHSS, being similar in the six women who developed OHSS compared with nine women without OHSS. The trends in progesterone concentrations were unrelated to any aspects of the clinical outcome.