Depo-Provera in adolescents: effects of early second injection or prior oral contraception

To examine the effects of an early second injection or prior use of oral contraceptive pills (OCP) on side effects of Depo-Provera during the early months of use in adolescents.

Thirty-six girls, gynecologic age 4.2 +/- 0.3 years, and body mass index (BMI) 23.2 +/- 0.8, received the currently recommended injection of 150 mg every three months. Twenty-seven girls (gynecologic age 3.9 +/- 0.5 years, BMI 24.0 +/- 0.8) received the second injection six weeks after the first injection. Fifteen girls (gynecologic age 5.0 +/- 0.5, BMI 25.4 +/- 1.3) switched directly from an OCP to Depo-Provera. The patients were periodically assessed by their care providers.

Early administration of the second injection of Depo-Provera did not alter the bleeding episodes, onset of bleeding, or total days of bleeding (14.3 +/- 3.7 vs. 17.1 +/- 4.0, p = 0.62) during the three months interval following injection, compared with the standard second injection interval. Moreover, an excessive BMI gain (BMI increase 0.99 +/- 0.22 vs. 0.40 +/- 0.14, p = 0.03) was observed in these girls. Girls who switched directly from OCP showed no difference in the rate of BMI gain when compared to those not previously on OCP (BMI increase 0.38 +/- 0.3). Bleeding duration of these girls, however, was markedly reduced; the total number of days of bleeding was 5.7 +/- 1.9 (p = 0.0003) during the first three month interval, and 5.7 +/- 2.3 (p = 0.019) during the three month period following the second injection. This reduction did not persist beyond the first six months.

Early second Depo-Provera injection does not alter the experience of menstrual abnormalities, and predisposes to greater weight gain; OCP use prior to Depo-Provera results in a decrease in the duration of bleeding with no change in the weight gain rate.