Progesterone Linked to Brain Structure Changes

MRI study finds stronger associations than estradiol across menstrual phases

By
Meg Barbor
March 30, 2026
2 min

MDSpire News

Objective:

To investigate the influence of sex hormone fluctuations on brain structure, focusing on progesterone and estradiol across the menstrual cycle.

Approach:

Key Findings:

Total gray matter volume was significantly higher during the periovulatory phase compared to menstruation.
Progesterone levels correlated with region-specific differences in gray matter volume and cortical thickness.
Higher progesterone during the periovulatory phase was linked to greater volume in cerebellar regions.
During menstruation, associations were found in frontal regions related to emotion and decision-making.
Estradiol showed fewer and less consistent associations with brain structure.
Cortical thickness exhibited phase-dependent associations across various brain regions.

Interpretation:

The study suggests that progesterone may significantly influence brain structure, with effects varying by menstrual phase, while estradiol's impact is less pronounced.

Limitations:

The sample size was small and consisted only of healthy women.
The luteal phase was not included in the study, limiting generalizability.

Conclusion:

Progesterone appears to play a crucial role in hormone-related structural variations in the brain, with distinct effects observed between menstrual phases.