Women who used hormonal birth control showed significantly greater gray matter volume in temporal, occipital, and frontal brain regions compared to non-users, with longer duration of use correlating with larger fusiform gyrus volume. Combined birth control and menopausal hormone therapy users demonstrated even more pronounced benefits, including greater parietal and temporal volume plus thicker posterior cingulate cortex. Later menopause onset also correlated with preserved posterior cortical thickness.
These findings challenge the mixed literature on hormone therapy's brain effects by examining lifetime exposure patterns rather than isolated treatment periods. The structural preservation observed decades after hormone use suggests potential long-term neuroprotective mechanisms, possibly through estrogen's known effects on synaptic plasticity and neurogenesis. However, this observational study cannot establish causation, and self-reported hormone histories introduce recall bias. The exclusively older, predominantly white cohort limits generalizability. While encouraging for understanding women's brain aging, these results require replication in diverse populations with objective hormone exposure data before informing clinical recommendations about contraceptive choices or hormone replacement therapy timing.
