We investigated the relationship between headache occurrence and phase of the menstrual cycle in a 4-month daily diary study of 74 women, 22 to 29 years old, residing in Washington County, Maryland. We selected subjects from women reporting a history of migraine symptoms and at least two migraine headache attacks per month in a 1986 to 1987 population-based survey. Data collection was from March 1987 through April 1988. By using detailed headache symptom information collected daily, we classified headaches into four categories: migraine with aura, migraine without aura, tension-type, and all other headaches. Odds ratios were separately estimated for the individual headache types and all types combined during each of three phases of the menstrual cycle. Risk of migraine without aura was significantly elevated during the first 3 days of menstruation (odds ratio, 1.66; 95% confidence interval, 1.21 to 2.26), but headache risk was not significantly increased during the 2 days immediately preceding onset of menstruation or on the estimated day of ovulation (day 14 before the onset of menstruation). Participants reported headaches on 28% of the study days overall, suggesting that onset of menstruation is an independent but not exclusive precipitating factor for headache attacks among young adult women with migraine. Our data show that onset of menstruation only accounts for a small proportion of migraine attacks among young women with frequent episodes of migraine.
