Effects of Two Estradiol/Norgestrel Combinations on the Ovulatory Pattern and on Sex Hormone Binding Globulin Capacity in Women Around Forty Years of Age

. Thirteen women aged 36—46 years (mean 43) who were seeking contraceptive advice, were monitored for 3 months with basal body temperature (BBT) and were then treated for 3 months with Cyclabil R (11 tablets of 2 mg es‐tradiol valerate (E 2 ) followed by 10 tablets of 2 mg E 2 + 0.5 mg norgestrel). This treatment was immediately followed by another 3 months with Cyclabil R + 2 mg E 2 . BBT revealed a spontaneous ovulatory rate of 89%. Cyclabil reduced the ovulatory rate, as measured with repeated serum progesterone analyses, to 37%, and Cyclabil + 2 mg E 2 resulted in a marked reduction in the number of ovulations (3 %). Both types of hormonal combination resulted in relatively small changes in Sex Hormone Binding Globulin Capacity. It is concluded that the addition of 2 mg E 2 to Cyclabil R causes a decrease in ovulation rate to such an extent that women using this combination run a relatively small risk of conceiving. One advantage over contraceptive steroids may be that the present combination contains a natural estrogen at a relatively low concentration.