Menstrual migraines not harder to treat: response to initial treatment

OB/GYN News, Sept 15, 2003 by Patrice G.W. Norton

CHICAGO--A new study suggests there is no significant difference in the way menstrual-related and nonmenstrual migraines respond to initial treatment.

There was no significant difference between the two groups in associated symptoms, severity, duration, disability, and initial treatment outcomes, Brenda F. Pinkerman, a Ph.D. candidate at Ohio University, Athens, reported at the annual meeting of the American Headache Society.

These findings run contrary to the common belief that menstrual migraines are more difficult to treat. Migraines are more likely to occur during the menstrual window, but evidence that they are harder to treat remains largely anecdotal. Some studies have suggested that menstrual-related migraines are more severe or of longer duration, but Ms. Pinkerman said that her findings did not bear this out.

"We did find that migraines were 1.6 times more likely to occur during that time, so it does appear the drop in estrogen levels is a potentially potent trigger," she said. But the findings didn't show any difference in the way that menstrual migraines responded to treatment or in the overall features of such migraines.

Menstrual-related migraines were defined as occurring 2 days prior to and during the first 3 days of menses. Patients had fewer than 20 headache days per month, and averaged nine migraines per month. About 47% of the patients also had headaches that weren't migraines.

Ms. Pinkerman and her associate Kenneth Holroyd, Ph.D., analyzed the daily computer diary entries of 92 menstruating women aged 18-56, who treated 181 menstrual-related migraines and 655 nonmenstrual migraines with abortive medications including combinations of analgesics, antiemetics, and triptans. Rescue medications also were prescribed for abortive therapy failures.

About 43% of the patients reported headache relief within 4 hours for both menstrual-related migraine attacks and nonmenstrual migraines.

Other outcomes were equally comparable: 14% of patients with menstrual-related migraines were pain free at 2 hours, compared with 15% of patients with nonmenstrual migraines; 3.5% of patients in both groups used rescue medications; and 3.5% of patients in both groups failed treatment. Both groups scored a 3 on a scale of 1-10 of all symptoms including nausea, vomiting, and sensitivity to light and sound. But migraine recurrence after becoming pain free was more likely in patients with menstrual-related migraines than in those with nonmenstrual migraines, 30% and 21% respectively.

"My theory as to why it recurs more often is that the trigger doesn't go away," Ms. Pinkerman said. "You can't avoid the trigger. So the question is whether the headache has been successfully treated or is it recurring because the trigger is still there?"

The subjects were part of a larger study examining the effectiveness of pharmaceutical and over-the-counter therapies for frequent, disabling migraines. Given that the study population had about 20 headache days per month, members of the audience asked whether some of the headaches might have fallen by chance within menses and were due to other causes.

Ms. Pinkerman agreed the next step would be to study a true menstrual migraine population, and said that the only way to define if a woman has menstrual-related or true menstrual migraines is to track them over a 3-month period to see if at least 90% of headaches occur during the menstrual window.