Return of ovulation and fertility in women using norethisterone oenanthate.

The return of ovarian activity was studied in 20 women who had discontinued norethisterone oenanthate after using the injectable contraceptive for 6 months to 5 years. Follicular activity returned within 70 days of discontinuing in four women and within 90 days in a further seven. In only 4 women was the return of follicular activity associated with a rise in the serum progesterone level. The serum norethisterone concentration was usually less than 1 ng/ml at the time of return of ovarian activity and was lower in women in whom ovarian activity returned before day 90 than in those in whom it returned after day 90. Of 40 women who discontinued norethisterone oenanthate, pregnancy occurred in 14 women within 12 weeks of discontinuing and in 21 (52.5%) within 6 months. The findings suggest that there is no impairment of fertility in women using norethisterone oenanthate.