The Effects of Oral Contraceptives on Body Composition After Resistance Training Interventions: A Systematic Review

The use of oral contraceptives (OC) alters hormonal levels and may impact body composition, which is an important factor concerning health and physical performance. This systematic review investigated the effects of OC on body composition of young women after resistance training. Four databases (PubMed, Web of Science, Scopus, and Embase) were searched in April 2023. Inclusion criteria consisted of (a) women between 18 and 40 years old and with no menopause symptoms; (b) women OC and non-OC users (control group); (c) resistance training intervention studies; and (d) intervention should last at least 8 weeks. A total of 7 studies were included for systematic review. Four studies observed increased lean mass and thickness of type II muscle fibers and reduced body fat for the non-OC users at post-resistance training compared with pre-resistance training. One study reported an increase in type I fiber cross-sectional area only in the OC group, whereas 2 studies reported no significant differences in body composition between groups throughout the intervention. In conclusion, considering that minimal changes in body composition may impair performance, some caution would be advised given the OC effects, especially for female athletes.