Sex hormone-binding globulin, oestradiol-17 beta, progesterone and testosterone at stimulation and after embryo transfer during in-vitro fertilization.

Serum concentrations of sex hormone-binding globulin (SHBG), oestradiol-17 beta progesterone and testosterone were measured in 23 gonadotrophin-stimulated menstrual cycles and in the implantation period [days 11-19 after human chorionic gonadotrophin (HCG) injection] following in-vitro fertilization and embryo transfer. Nine cycles resulted in successful pregnancies, one pregnancy ended in spontaneous abortion (week 14) and 13 cycles were without conception. SHBG levels were significantly elevated above pretreatment values from day 3 after HCG injection onwards. A significant positive correlation was found between increments in SHBG (delta SHBG) during the luteal phase and oestradiol/testosterone ratios during the follicular and luteal phases. In the pregnant cycles a significant positive correlation was also found between delta SHBG during the implantation period and oestradiol/testosterone ratios during the luteal phase and the implantation period. Significant negative correlations were found between delta SHBG and testosterone during the luteal phase in pregnant and non-pregnant women as well as between delta SHBG during the period corresponding to implantation and testosterone during the luteal phase in non-pregnant cycles. The results may reflect a modulating action of the oestrogen/androgen balance upon SHBG levels in subjects with supraphysiological oestradiol levels, such as in stimulated cycles and in very early pregnancy.