OBJECTIVE: Our goal was to evaluate both the continuation and pregnancy rates and the side effects experienced during the first year of use by adolescents who selected Norplant implants as compared with those who chose oral contraceptives for contraception. Furthermore, side effects experienced at 6 versus 12 months among Norplant implant users were compared to determine whether they diminished with continued use of this method.

STUDY DESIGN: We conducted a case-control study of 56 adolescents ≤18 years old who selected implants as compared with 56 age-matched controls who chose oral contraceptive pills during the same time period.

RESULTS: Only 34% of patients prescribed oral contraceptives as compared with 91% of Norplant implant patients were still using their chosen method 1 year later. As a result 25% of oral contraceptive users became pregnant within 12 months as compared with none who selected Norplant implants. Side effects were reported by >80% of patients in both groups, with menstrual irregularities reported more often by Norplant implant users than by oral contraceptive users (73% vs 5%, p = 0.01). Furthermore, Norplant implant users gained more weight than oral contraceptive users (8.7 vs 4.2 pounds) and were twice as likely to have an abnormal Papanicolaou smear. Finally, little diminution in side effects was observed during the second 6 months of Norplant implant use.

CONCLUSIONS: These data confirm that Norplant implants provide better protection against unintended pregnancy in an adolescent population but may be associated with more side effects. Clinicians should be aware of these findings so they can adequately counsel young patients about these two methods of contraception.(Am J Obstet Gynecol 1997;176:586-92