Weight change in adolescents who used hormonal contraception.

PURPOSE

(a) To compare weight change at 1 year between adolescents 13-19 years old who were using either depot medroxyprogesterone acetate (DMPA) or oral contraceptives (OC), and (b) to determine if age, baseline body mass index (BMI), race/ethnicity, or weight gain at 3 months predicted which subjects would gain excessive weight.

METHOD

The setting was a Planned Parenthood Teen Clinic with chart review of variables of interest. Excessive weight was defined as weight gain > 10%.

RESULTS

Baseline variables were similar in the two groups, except that DMPA users (n = 44) had a greater mean BMI (t test, p = .05) than OC users (n = 86). Mean (standard deviation) and median weight gains at 1 year were 3.0 (4.5) and 2.4 kg in the DMPA users and 1.3 (3.9) and 1.5 kg in the OC users (difference in medians not significant, Wilcoxon rank sum test, p = .10). Fifty-six percent of DMPA and 70% of OC users lost weight or gained < 5% of their baseline weight (p = .17, Fisher exact test); 25% of DMPA users and 7% of OC users gained > 10% of their baseline weight (p = .006). Age, baseline BMI, or race/ethnicity did not affect the likelihood that either group would gain > 5% or > 10% of their baseline weight. Of adolescents who gained > 5% of baseline weight at 3 months, 13 of 14 (93%) gained even more weight at 12 months.

CONCLUSIONS

The majority of adolescents who used hormonal contraception for 1 year lost weight or gained < 5% of baseline weight. DMPA users were more likely than OC users to gain > 10%. Subjects who gained > 5% of baseline weight at 3 months were at high risk (93%) of gaining even more weight by 1 year.