Return to ovulation following the use of long-acting injectable contraceptives: a comparative study.

A comparative study was undertaken in twenty-four Mexican women who discontinued the use of depo-medroxyprogesterone acetate (DMPA) or norethisterone enanthate (NET-EN) to assess the time required for the return to menses and ovulation. All subjects were exposed to long-acting injectable contraceptives for at least one year, and were followed prospectively. Serum progesterone levels were determined weekly in all subjects beginning 3 months after the last progestogen injection. Mean time to return to ovulation occurred significantly earlier (p less than 0.001) after NET-EN (2.6 months) as compared with DMPA (5.5 months). No correlation between the return to ovarian function and the duration of steroid exposure was found. The overall data was interpreted as demonstrating a clear-cut difference between the two long-acting progestogens in terms of ovulation suppression.