The Effects of Oral Contraceptives on Exercise Performance in Women: A Systematic Review and Meta-analysis.
Level 1 - systematic review of randomized trials
Systematic review and meta-analysis of comparative trials
PubMed 32666247 · doi:10.1007/s40279-020-01317-5
What was done
A PRISMA-compliant systematic review and Bayesian meta-analysis evaluating the effects of oral contraceptive pills (OCPs) on exercise performance in women. Investigators evaluated between-group comparisons (habitual OCP users vs. naturally menstruating women phase-matched at OCP withdrawal vs. early follicular phase, and active consumption vs. other phases) and within-group comparisons (active OCP consumption vs. withdrawal). Methodological quality was appraised using a modified Downs and Black checklist and GRADE methodology.
What was found
42 studies comprising 590 participants met inclusion criteria; 83% were graded as moderate, low, or very low quality, and 17% as high quality. For between-group comparisons, the probability of at least a small effect (d ≥ 0.2) favoring OCP users was near zero (p < 0.001). The probability of a small effect favoring naturally menstruating women was moderate for OCP withdrawal vs. early follicular phase (d ≥ 0.2; p = 0.40) and small for OCP consumption vs. non-early follicular phases (d ≥ 0.2; p = 0.19), with substantial between-study variance (tau = 0.16 [95% CrI 0.01–0.44] and tau = 0.22 [95% CrI 0.06–0.45], respectively). Within-group comparison of active OCP consumption versus withdrawal showed virtually zero probability of a small effect in either direction (d ≥ 0.2; p ≤ 0.001).
Why it matters
OCP use is associated with trivial, group-level decreases in exercise performance relative to natural menstrual cycles, with stable performance across active and withdrawal phases. These findings do not support broad guidelines discouraging OCP use for athletic performance, favoring individualized assessments.
Limits
The majority of included trials exhibited moderate, low, or very low methodological quality. The total sample size was small relative to the number of studies (590 total participants across 42 trials, ~14 per study). Substantial between-study heterogeneity was present, and the abstract does not report sub-analyses by specific OCP formulation, athletic training level, or exercise modality.
Cited by
- supports The downregulation of endogenous hormones caused by hormonal contraceptives does not impact exercise performance or training adaptations.