Migraines and Fluctuating Female Sex Hormones

The Role of Female Sex Hormones in Migraines

Migraines can be influenced by fluctuating female sex hormones. The relationship between female sex hormones and calcitonin gene-related peptide (CGRP) is particularly significant in the onset of migraines. CGRP is a molecule that plays a crucial role in triggering migraine episodes. Research indicates that changing levels of sex hormones, especially estrogen, may enhance CGRP activity, resulting in migraine attacks. Studies show that women experiencing migraines have elevated CGRP levels in their blood and tear fluid during menstruation, reinforcing this connection.

Understanding the Biology of Migraines

The mechanisms behind migraines are intricate and not yet fully understood. The trigeminal nerve, which is responsible for facial sensory perception, releases CGRP that causes blood vessels in the head to dilate. During migraine episodes, this trigeminal system also releases CGRP, and medications that inhibit CGRP activity have been found to alleviate migraine symptoms.

The Menstrual Cycle and CGRP Interplay

Migraines tend to occur more frequently and with greater severity just before menstruation and during peri-menopause, when estrogen levels are at their lowest. This phenomenon is encapsulated in the estrogen withdrawal hypothesis, which posits that rapidly decreasing estrogen levels can trigger migraines. While some individuals find relief from migraines through birth control methods that stabilize hormone levels, others may experience worsening symptoms.

Investigating the Mechanisms Behind Migraines

Research has suggested that low estrogen levels may facilitate CGRP release, leading to migraines. Those suffering from migraines have shown higher CGRP levels in their tear fluid, highlighting the role of the trigeminal system. This has prompted further studies on CGRP levels throughout various stages of the menstrual cycle in women.

Research Study on CGRP Levels and Female Sex Hormones

Study Overview

A group of researchers aimed to analyze CGRP levels alongside changes in female sex hormones among women with and without migraines. Participants were categorized into three subgroups: fertile women with regular menstruation, women using hormonal contraceptives, and post-menopausal women.

Findings Among Women with Regular Menstrual Cycles

During ovulation and just before menstruation, women with migraines exhibited higher CGRP levels in their tear and blood samples compared to those without migraines. Additionally, women with migraines had lower estrogen levels than their counterparts during ovulation, while levels of other female hormones were comparable across both groups at these time points.

Results for Women on Hormonal Contraceptives

In women using hormonal contraceptives, CGRP concentrations were similar for both migraine sufferers and non-sufferers during hormone-free and hormone-intake periods. Women without migraines had lower estrogen and other hormone levels during both intervals, while testosterone levels remained consistent.

Findings in Post-Menopausal Women

Among post-menopausal participants, hormone levels did not significantly differ between those with and without migraines, nor were CGRP levels markedly different.

Interpreting the Results

The study indicated that women suffering from migraines had elevated CGRP levels compared to those without migraines, a trend not observed in post-menopausal women or those using hormonal contraception. The fluctuations in hormone levels, rather than their absolute levels, appeared to correlate with CGRP levels. This aligns with the estrogen withdrawal hypothesis, where increased CGRP was linked to the drop in estrogen preceding menstruation. Such insights may clarify the prevalence and intensity of migraines during the peri-menstrual phase. Notably, elevated CGRP levels have also been identified in areas unrelated to the trigeminal nerve in pregnant and post-menopausal women, suggesting the influence of additional mechanisms, especially during pregnancy when estrogen levels are elevated.

Future Research Directions

Further exploration of the relationship between CGRP sourced from the trigeminal system in tear fluid and migraines could provide deeper understanding of how female sex hormones impact migraine occurrence.

References

1. Edvinsson L. CGRP and migraine: from bench to bedside. Rev Neurol (Paris). Sep 2021;177(7):785-790. doi:10.1016/j.neurol.2021.06.003
2. Raffaelli B, Storch E, Overeem LH, et al. Sex Hormones and Calcitonin Gene-Related Peptide in Women With Migraine: A Cross-sectional, Matched Cohort Study. Neurology. Apr 25 2023;100(17):e1825-e1835. doi:10.1212/wnl.0000000000207114
3. Clinic C. Trigeminal Nerve. Accessed May 25, 2023. https://my.clevelandclinic.org/health/body/21581-trigeminal-nerve#:~:text=The%20trigeminal%20nerve%20is%20the,help%20you%20chew%20and%20swallow.
4. Kamm K, Straube A, Ruscheweyh R. Calcitonin gene-related peptide levels in tear fluid are elevated in migraine patients compared to healthy controls. Cephalalgia. Oct 2019;39(12):1535-1543. doi:10.1177/0333102419856640