Randomized Controlled Trial of Aerobic Exercise on Body Mass Index Reduction in Women Using Injectable Contraceptives

Abstract

Background: Injectable contraceptive use is frequently associated with body mass index (BMI) increase due to progesterone-induced fat accumulation. Aerobic exercise may help counteract these effects by enhancing energy expenditure and fat oxidation.

Objective: To determine the effect of moderate-impact aerobic exercise on BMI reduction among overweight women using injectable contraceptives.

Methods: A randomized controlled trial with a two-group pretest–posttest design was conducted among 32 overweight women aged 25–35 years using injectable contraceptives. Participants were randomly assigned to an intervention group (n=16) or control group (n=16). The intervention group performed moderate-impact aerobic exercise three times weekly for four weeks, while the control group maintained usual activities. BMI was measured before and after the intervention. Data were analyzed using paired and independent t-tests with a significance level of 0.05.

Results: The intervention group demonstrated a significant BMI reduction from 27.4 ± 1.2 to 26.6 ± 1.1 kg/m², with a mean change of −0.84 ± 0.41 (p<0.001). The control group showed no significant change (−0.06 ± 0.29; p=0.326). Between-group analysis revealed a significantly greater BMI reduction in the intervention group (mean difference −0.78; 95% CI −1.02 to −0.54; p<0.001).

Conclusion: Moderate-impact aerobic exercise significantly reduced BMI among overweight women using injectable contraceptives and may serve as an effective non-pharmacological weight management strategy.