Pharmacokinetics, ovulation suppression and return to ovulation following a lower dose subcutaneous formulation of Depo-Provera

Depo-Provera is a highly effective contraceptive, given intramuscularly (150 mg/mL) once every 3 months. It has been in use in the United States for over 10 years. A new lower-dose formulation of Depo-Provera (104 mg/0.65 mL), has been developed that allows subcutaneous injection, potentially increasing the convenience, ease of administration and tolerability of this contraceptive. This prospective, randomized, single-center, single-dose trial evaluates the pharmacokinetics of the lower-dose formulation of Depo-Provera and compares the lower-dose formulation to the original formulation with regard to efficacy and duration of ovulation suppression and the return to ovulation at 12 months. While delivering a 30% lower total dose than the intramuscular formulation, the lower-dose formulation of Depo-Provera suppressed ovulation for more than 13 weeks in all subjects and was not affected by body mass index or race. Median time for return to ovulation was 30 weeks, with a 97.4% cumulative rate of return to ovulation at 12 months.