Adolescent use of the monthly contraceptive injection

Abstract

Study objective: To compare weight and continuation among adolescents using monthly medroxyprogesterone acetate (MPA)/ethinyl estradiol cypionate (E2C), tri-monthly depot MPA (DMPA), and daily oral contraceptive pills (OCP).

Design: Medical records were reviewed for body mass index, demographics, and sexual history at baseline; and weight and continuation at 3, 6, 9, and 12 months. Bivariate analyses were performed by method, and continuation functions were compared by the log-rank and Wilcoxon tests. The effect of method on use duration was assessed by Cox regression.

Setting: Hospital adolescent clinic.

Participants: 12- to 21-year-old patients who initiated MPA/E2C, DMPA, or OCPs in 2001.

Main outcome measures: Weight gain and method continuation.

Results: MPA/E2C was initiated by 40 (18%) patients, DMPA by 63 (28%), and OCPs by 119 (54%, P < 0.001). OCP users were younger (P = 0.005) and more likely to be white, privately insured, and in school (P < 0.004) than MPA/E2C or DMPA users. Previous DMPA and OCP use, pregnancy, and sexually transmitted infections (STI) were more common among MPA/E2C than DMPA or OCP users (P < or = 0.001). Baseline BMI was lowest (P = 0.06) among DMPA users, and MPA/E2C users were most likely to be overweight (P = 0.03). There were non-significant differences in weight change. Continuation functions differed by the method only in the first three months of use (P = 0.03). Leading reasons for discontinuation were unavailability of MPA/E2C (20%), bleeding with DMPA (22%), and forgetting OCPs (17%). Duration of use was independently associated with white race (P < 0.005) and STI-never (P < 0.0001) but not with method type.

Conclusions: Although MPA/E2C use was associated with overweight status and early discontinuation, it also was associated with previous use of other methods. For all methods, poor continuation at one year supports the ongoing search for effective contraceptive alternatives.