Headache, with migraine in particular, is known to be more frequent among females. It is clear that sex hormones influence the prevalence of both migraine and other types of headache. Before puberty, prevalence of migraine is similar for both sexes. In the years after puberty most new migraine sufferers are young females. In adults, migraine is roughly three times more common in women than in men. Reproductive life events such as menarche, menstruation, pregnancy and menopause all influence the prevalence of migraine. Migraine often debut around menarche, and occur more frequently with menstruation. Menstrual migraine headaches tend to be more severe than headaches that occur outside menstruation. Pregnancy tends to have an improving effect on migraine, the second and third trimester in particular. After menopause, prevalence of headache decreases.
Exogenous sex hormones are also thought to influence headache prevalence. Drugs containing estrogens are thought to worsen migraine, and use of these is often avoided by headache sufferers. This review examines literature on the effect of combined oral contraceptives (COC) and hormonal replacement treatment (HRT) on headache. Studies included are both clinical studies and population studies.
The population studies showed significant increase in headache with both use of COC and HRT, for migraine in particular. The clinical studies had more ambiguous results. Some increase in headache in women who used COC or HRT was seen in a few of the studies, but several of the studies concluded that no significant increase could be found. The clinical studies tended to be older, and the doses of estrogen used were higher than today’s standards.
Connections can be drawn between the use of COC and HRT and headache, but newer clinical studies with thoroughly randomized control groups and double blinding are still required to answer the question of how estrogen-containing drugs influence headache prevalence.