NEW YORK, Dec 04 (Reuters Health) - Women who suffer migraines are twice as likely to have one during the first 2 days of their menstrual period than during the rest of the month, new research shows.
　　A study of 81 women suggests that those at risk of migraine are also more likely to have an attack in the 2 days before their period begins. On the other hand, migraine risk appears to drop during ovulation.

However, while these findings link women's migraines to the menstrual cycle, they do not support the idea that so-called "menstrual migraines" are worse than those that occur during the rest of the month, the researchers report in the November 28th issue of Neurology.

Dr. Walter F. Stewart of the Johns Hopkins School of Hygiene and Public Health in Baltimore, Maryland led the study. He and his colleagues had the women record their migraine symptoms and menstrual patterns over 98 days.

The investigators found that the women's migraine risk doubled during the first 2 days of their periods, and increased 80% during the 2 days before menstruation. During ovulation, however, the women had a 56% lower risk of migraine. The findings applied only to migraines without aura; migraines with aura are preceded by a short bout of abnormal vision or other physical signs that a migraine is coming. Most people have migraines without aura.

Stewart's team did not find that migraines during menstruation were more intense or longer-lasting than other migraines. This, the authors report, contradicts the "clinical notion" that menstrual migraines are worse than those occurring during the rest of the month.

About three quarters of migraine sufferers are women, and hormone fluctuations are believed to play a role in women's migraines. According to Stewart and his colleagues, these findings suggest that monthly hormone changes "may alter the risk of attacks, but not the characteristics of the attacks."

The researchers suggest that the estrogen drop that comes just before a woman's period may trigger a migraine.

(From Reuters)