Migraine is one of the clearest sex-skewed neurological disorders. In adulthood, women experience migraine far more often than men. That fact is sometimes compressed into a simple explanation: women must carry more genetic migraine risk, or migraine in women is basically a hormone problem.
Twin research complicates both stories. In a Swedish Twin Registry analysis of 51,872 people, women had far more migraine without aura than men, yet the overall heritable component could be modelled as roughly equal across sexes. Hormones still matter — but as modifiers of a susceptible nervous system, not as a single universal cause.
Quick answer
Is migraine more common in women because it is more strongly genetic in women?
The best large twin evidence says no. Women had much higher migraine-without-aura prevalence, but broad-sense heritability was about 0.45 and could be equated across women and men in the main model. Current evidence instead supports an interaction between inherited susceptibility, reproductive-hormone transitions, trigeminovascular/CGRP biology and nonshared environmental factors.
Key takeaways
- A Swedish Twin Registry study analysed 51,872 twins and found migraine without aura in 17.6% of women versus 5.5% of men.
- The study estimated broad-sense heritability at about 0.45 and did not find a stronger overall genetic contribution in women in its full ADE model.
- A 2024 scoping review identified 52 migraine twin studies; adult heritability estimates were commonly around 0.36–0.48.
- Hormonal transitions across puberty, menstruation, pregnancy and perimenopause can modify migraine expression, but the direction and magnitude are not identical for every person.
- Estrogen–CGRP and trigeminovascular mechanisms are biologically plausible, but they do not yet form one fully established causal chain explaining the entire sex difference.
- An opposite-sex co-twin finding raises a prenatal neuroendocrine hypothesis but does not prove testosterone transfer or prenatal androgen causality in humans.
The paradox: much more migraine in women, but not more heritability
In the Swedish Twin Registry study, 17.6% of women met criteria for migraine without aura compared with 5.5% of men. Yet when additive and non-additive genetic influences were modelled together, the broad-sense heritability estimate was about 45% and could be equated across the sexes.
That is an important distinction. A condition can be more common in one sex without the genetic contribution to variation being larger in that sex. Prevalence and heritability answer different questions.
What equal heritability does — and does not — mean
Heritability describes how much variation in liability is statistically associated with genetic differences in a particular population. It does not say that 45% of one person’s migraine is genetic, and it does not mean women and men have identical migraine biology.
The same overall heritability can coexist with different hormone environments, gene expression, neural sensitivity, life-stage exposures and nonshared environmental factors. A reduced model in the Swedish study even suggested subtle qualitative genetic differences, although the full model did not support a simple sex-specific genetic explanation.
Hormones matter most as changing context, not a single switch
Migraine expression changes across life stages in ways that point to reproductive hormones. Puberty, the menstrual cycle, pregnancy and perimenopause are all periods when migraine patterns can shift in some people.
But “hormones matter” is not the same as “estrogen causes migraine”. Hormone levels fluctuate together with receptors, neural excitability, vascular signalling, sleep, stress and other biology. Some people show strong menstrual associations; others do not.
Why estrogen withdrawal gets so much attention
Clinical and experimental research has repeatedly linked periods of falling or unstable estrogen with increased migraine susceptibility in some women. That helps explain why menstrual and perimenopausal transitions are scientifically important.
Still, an association with hormonal change does not imply a universal trigger rule. Migraine can occur outside reproductive transitions, and the same hormonal event does not produce the same response in every susceptible person.
CGRP gives the hormone story a neural pathway
CGRP is a key signalling molecule in migraine biology and a major therapeutic target. Estrogen receptors and CGRP-related pathways intersect in trigeminovascular and neuroimmune systems, creating a plausible mechanism through which hormonal state can modify migraine susceptibility.
A 2026 review describes this estrogen–CGRP axis as an important framework, but it also emphasizes a major scientific gap: humans have not yet provided one complete causal chain showing that estrogen withdrawal directly raises CGRP signalling and thereby explains the female migraine excess.
The opposite-sex twin result is intriguing — and easy to overstate
The Swedish study also compared women with a male co-twin to women with a female co-twin. Unexpectedly, women with a male co-twin had higher migraine risk. The authors had originally hypothesized the opposite under a simple prenatal masculinization model.
That result raises questions about prenatal neuroendocrine development, but it does not measure fetal testosterone transfer and cannot identify a specific hormone mechanism. It should remain a hypothesis-generating finding, not a headline that “a male twin causes migraine”.
Why migraine subtype matters
The Swedish analysis focused on migraine without aura because registry interviews could not reliably classify migraine with aura to current diagnostic standards. That boundary matters because migraine with and without aura overlap but are not interchangeable phenotypes.
The broader twin literature also has relatively little subtype-specific evidence. Any claim about “migraine in women” therefore needs to acknowledge that different migraine phenotypes may not share identical genetic, hormonal or vascular mechanisms.
What 52 twin studies add to the picture
A 2024 scoping review identified 52 migraine twin studies across seven countries. Adult heritability estimates were remarkably consistent, commonly around 0.36–0.48, reinforcing a real inherited susceptibility.
At the same time, the review highlights limitations: most cohorts were of North-European ancestry, only a small number examined migraine subtypes, and discordant-twin designs remain underused. The field knows more about background heritability than about why one genetically similar person crosses the threshold into attacks at a particular life stage.
A better model: susceptibility plus modifiers
The most defensible model is layered. Genetic susceptibility sets part of the background. Reproductive hormones can alter neural and trigeminovascular sensitivity. CGRP and related pathways participate in attack biology. Sleep, stress, medication, sensory exposures and other nonshared factors can further shift the threshold.
This model explains why women can have a much higher prevalence without requiring migraine to be “more genetic” in women, and why hormones can be important without being the whole disease.
TwinPare boundary
TwinPare can help users keep a chronology of symptoms alongside sleep, activity and recovery context that may be worth discussing with a healthcare professional. That is pattern awareness, not diagnosis or prediction.
TwinPare does not measure estrogen, progesterone or CGRP, determine migraine subtype, predict menstrual migraine or recommend contraception, hormone therapy or migraine medication. Individual migraine and reproductive-health decisions belong with qualified healthcare professionals.
Source notes
The sources have been verified and editorially reviewed for this article. The limitations below show which level of conclusion the sources support.
- [fitzgerald-sex-differences-migraine-twins-2021] Sex Differences in Migraine: A Twin Study Morgan C Fitzgerald; Ursula G Saelzler; Matthew S Panizzon. Frontiers in Pain Research, 2021. Evidence type: Swedish Twin Registry sex-limitation and opposite-sex co-twin study Limitation: The analytic sample included 51,872 twins and 18,828 complete pairs. Migraine without aura prevalence was 17.6% in women versus 5.5% in men, while broad-sense heritability was estimated at 0.45 and could be equated across sexes in the full ADE model. Females with a male co-twin had higher migraine risk than females with a female co-twin (OR 1.51, 95% CI 1.26–1.81); this observational result does not prove a prenatal hormone mechanism. The authors declared no commercial or financial competing interests. PubMed PMC DOI
- [olofsson-migraine-twin-scoping-review-2024] Migraine heritability and beyond: A scoping review of twin studies Isa Amalie Olofsson. Headache, 2024. Evidence type: Scoping review of 52 migraine twin studies Limitation: Across adult twin studies, migraine heritability estimates commonly fell around 0.36–0.48. The evidence base was dominated by North-European cohorts and relatively few studies examined migraine subtypes. PubMed DOI
- [warfvinge-hypothalamic-sex-hormones-migraine-2026] Hypothalamic and sex-related hormones in migraine Karin Warfvinge; Jacob C A Edvinsson; Aida Maddahi; Lars Edvinsson. The Journal of Headache and Pain, 2026. Evidence type: Review of reproductive and hypothalamic hormone biology in migraine Limitation: The review describes migraine variation across puberty, menstruation, pregnancy and perimenopause and supports hormone-sensitive trigeminovascular mechanisms while emphasizing that the mechanisms remain incompletely explained. The authors declared no competing interests. PubMed PMC DOI
- [dag-estrogen-cgrp-axis-migraine-2026] The Estrogen-CGRP Axis in Migraine: Neuroimmune Mechanisms, Sex Differences, and Therapeutic Implications Muhlis Yiğitcan Dağ; Rukiye Ölçüoğlu. Molecular Neurobiology, 2026. Evidence type: Narrative review of estrogen–CGRP, trigeminovascular and neuroimmune mechanisms Limitation: The estrogen–CGRP framework is biologically plausible, but a direct causal human sequence from estrogen withdrawal through increased CGRP signalling to migraine has not been fully established. The authors declared no competing interests. PubMed DOI
Editorial source review
This section shows how the article's key factual claims are linked to the source.
Phrasings that require caution
- Do not say migraine is more heritable in women.
- Do not convert population heritability into a personal percentage.
- Do not say estrogen causes all migraine in women.
- Do not imply menstrual cycles, pregnancy or perimenopause affect every person in the same way.
- Do not say CGRP explains the entire female–male prevalence gap.
- Do not say the opposite-sex co-twin result proves prenatal testosterone transfer or androgen causality.
- Do not collapse migraine with aura and migraine without aura into one evidence claim.
- Do not provide individualized contraception, hormone-treatment, pregnancy or migraine-medication advice.
- Do not imply TwinPare diagnoses migraine or predicts attacks from hormone, HRV, sleep or wearable data.
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