From Confound to Crucial: Menstrual Cycle Hormones and Limits in Current Affective Neuroscience

Within the scientific community, hormonal variability in women has often been framed as a confounding factor that disrupts experimental outcomes. This oversimplification of the menstrual cycle has justified the use of male-only samples in neuroscience research. Although there is a prevalent increase in studies examining ovarian hormones as predictable neurobiological modulators, the long-standing exclusion of women from research has limited the generalizability of affective neuroscience models and contributed to real-world consequences for women’s health. Furthermore, when researchers include women in samples, methodological limitations, including small sample sizes and indirect measures of hormonal status, can lead to inconsistent findings. This review highlights the importance of treating ovarian hormones as meaningful biological variables associated with emotional regulation and emphasizes how improved study designs can support more accurate and equitable mental health research.