The start of a woman's menstrual cycle may trigger more than just cramps and mood swings. New research shows more women experience painful migraine headaches during the first 2 days of their menstrual cycle than at any other time of the month.

"Menstruation may be the most reliable trigger for migraine we have," says study author Stephen Silberstein, a neurologist and director of the Headache Center at Thomas Jefferson University Hospital in Philadelphia.

Researchers also found a higher risk of migraine during the 2 days before menstruation begins, and a lower risk around the time of ovulation. For the study, 81 women with clinically diagnosed migraine were asked to keep detailed diaries of their headaches for about 3 months. Participants were also asked to record symptoms and the extent of their disability (like days missed at work or reduced productivity).

Researchers found 28% of the migraines without aura (visual symptoms like blind spots or lights) reported by the women took place in the 4 days at the beginning of menstruation. There was also a greater chance of tension-type headache.

Silberstein says the findings will help doctors teach their patients to prepare and possibly avoid menstruation-related migraines by developing treatment programs that incorporate a woman's menstrual cycle. He says the findings are especially significant because 70% of migraine sufferers are women.

"If they know when they are most vulnerable, women can avoid things that might trigger a migraine such as drinking red wine, eating Chinese food with MSG and other things," says Silberstein.

But there was no evidence to support the idea that migraines during menstruation are more painful or more severe, according to Silberstein.

Although migraine patients often say headaches during menstruation are more severe, at least this study shows that researchers now know that they are more frequent during this time, says Meryl Diamond, MD, a neurologist at the Diamond Headache Clinic in Chicago.

"This proves what patients have been telling us for a while," Diamond says. "With this knowledge we can educate patients about the time they are most at risk for migraines and allow patients to take their medications preemptively, watch their sleeping patterns and eating habits, exercise, and do other healthful things to avoid a migraine."

Researchers say previous studies have shown that women's declining estrogen levels around menstruation may be the biggest trigger for headaches. Silberstein's study is published in the Nov. 28 issue of Neurology.

(From CBSHealthWatch)