Retrospective review of the relationship between weight change and demographic factors following initial depot medroxyprogesterone acetate injection in adolescents

Abstract

Background: Depot medroxyprogesterone acetate (DMPA) is an effective (<1% annual failure rate) contraceptive administered by intramuscular injection every 3 months. DMPA is an increasingly popular contraceptive choice for adolescents, yet its use is associated with weight gain as well as subsequent nonadherence and long-term obesity-related diseases and mortality. Precise risk factors for DMPA-associated weight gain and the time periods of greatest weight increases have not been reported. Knowledge of these factors may prompt individualized counseling and proactive approaches to minimizing weight gain during DMPA treatment.

Objective: This study evaluated the relationship between weight change at 10 to 14 weeks post-DMPA initiation and race, baseline weight, and gynecologic age (age at DMPA initiation minus age at menarche) in female adolescents.

Methods: Data for baseline and 10 to 14 weeks post-DMPA initiation were obtained via retrospective chart review of 115 female adolescents treated at Cincinnati Children's Hospital Medical Center. Descriptive statistics, 2-tailed t tests, and a multivariable linear regression model were used to evaluate weight gain and potentially associated characteristics.

Results: A total of 29 of 115 patients (25%) were excluded from the analysis owing to first post-DMPA initiation visit occurring later than 14 weeks, no recorded weight, and/or no documented age of menarche. For the 86 patients (75%) included in the analysis (study cohort), the mean (SD) baseline weight was 60.4 (14.0) kg (range, 36.4-114.8 kg), the mean (SD) age at initiation was 15.5 (1.3) years, the mean (SD) gynecologic age was 3.8 (1.6) years, and 83% of DMPA-treated adolescents were of black race. There was no significant difference in the mean weight change during the 10 to 14 weeks post-DMPA initiation by race; 0.19 kg for black patients versus -0.97 kg for non-black patients (P = 0.16; 95% CI of the difference, -0.49 to 2.81). For black patients, there was no significant difference in the mean weight change by gynecologic age (P = 0.58; 95% CI, -0.69 to 1.22). A multivariable linear regression model demonstrated that baseline weight (P = 0.60), race (P = 0.07), and gynecologic age (P = 0.88) were not significantly associated with weight change during the 10 to 14 weeks following DMPA initiation.

Conclusion: In this study cohort, race, gynecologic age, and baseline weight were not associated with weight gain 10 to 14 weeks following initiation of DMPA.