Objective: To compare the incidence of repeat pregnancy and method continuation rate at 12 months postpartum in young women who chose either depot medroxyprogesterone acetate or oral contraceptives (OCs) as contraception.
Methods: We conducted a prospective cohort study of 122 postpartum women younger than 18 years of age who delivered between January 8, 1997 and December 31, 1997. Patients choosing depot medroxyprogesterone acetate (n = 76) and OCs (n = 46) were accrued for 12 months and were followed-up for a minimum of 12 months. Main outcome measures were median contraceptive method continuation and the incidence of repeat pregnancy at 12 months postpartum.
Results: There was no difference in mean age at delivery (P =.47), parity (P =.84), or gravidity (P =.78) between depot medroxyprogesterone acetate and OC users. At 12 months postpartum, 27.4% of OC users and 55.3% of depot medroxyprogesterone acetate users were still using contraception. Median time to contraceptive discontinuation was longer for those choosing depot medroxyprogesterone acetate compared with OCs (17.8 vs 7.4 months, respectively, P =.002). The overall incidence of repeat pregnancy at 12 months postpartum was 10.6%. Among OC and depot medroxyprogesterone acetate users, respectively, 24% and 2.6% became pregnant again, producing a relative risk (RR) of 9.09 (95% confidence interval [CI] 2.1, 39.2) for repeat pregnancy among OC users. The mean time to repeat pregnancy (this was reported instead of the median time whenever the pregnancy rate had not reached 50% at the end of the follow-up period) was longer for depot medroxyprogesterone acetate compared with OC users (17.1 months vs 13.2 months, respectively, P <.001).
Conclusion: Adolescent mothers using depot medroxyprogesterone acetate injection for contraception have a higher method continuation rate and a lower incidence of repeat pregnancy at 12 months postpartum than those selecting OCs during the same period.