Does Balance Vary Across the Menstrual Cycle?: A Meta-Analysis with Implications for Women's Health.
Background: Women remain underrepresented across many domains of research, clinical science, and medicine. Sex differences other than the reproductive system, body composition, and size, are poorly understood. The menstrual cycle, for example, can be influenced using hormonal contraception methods. Hormonal fluctuations through the menstrual cycle go beyond the reproductive physiology and influence systems involved in balance and postural control. Data Sources and Methods: The search was conducted through the following databases: PubMed, Web of Science, Medline, SPORTDiscus and Scopus (up to March 6, 2026) for studies that looked for the effects of the menstrual cycle phases on balance in women using or not hormonal contraceptives. Standardized mean difference was used to estimate the effect of menstrual cycle phases on postural control and Hedges' g was reported to account for the small sample bias. Two multilevel mixed effects models, meta-regression, and sensitivity analyses were conducted. The funnel plot was used to determine if there was a publication bias. Thirteen studies were included in this meta-analysis. Results: For static balance tasks, the pooled effect size was small and not statistically significant (SMDH = -0.19, 95% CI = -0.41 - 0.02, p = .073). Similarly, no significant effect observed for dynamic balance tasks (SMDH = 0.18, 95% CI = -0.67 - 1.04, p = .44). The moderator analyses showed that contraceptive use did not significantly explain the variability in either static or dynamic balance outcomes. Conclusions: This meta-analysis demonstrated that current evidence does not establish a consistent effect of menstrual cycle phase on static or dynamic balance. High-quality studies with standardized menstrual cycle verification methods are needed to clarify the relationship between hormonal fluctuations and postural control in women. Registration: PROSPERO CRD420261402114. Keywords: Balance, postural sway, hormonal fluctuations, menstrual cycle phases, hormonal contraceptives.