AHS: Perimenstrual Migraines Recurrence Linked to The Pill

LOS ANGELES, June 30 ? Migraine related to menstruation may be exacerbated by hormonal birth control measures, with more use of analgesics and more recurrences, researchers said here.

"Women taking birth control could potentially benefit from taking a combination of triptans and NSAIDs to reduce migraine recurrence," said Brenda Pinkerman, Ph.D., a psychology resident at the James A. Haley Veterans' Hospital in Tampa, in an oral presentation at the American Headache Society meeting.

Previous studies have shown that headache is a frequently reported side effect of hormonal birth control and that for all women headaches are most likely to occur during the phase of the cycle with rapidly declining estrogen levels, which is during the drug-free phase for those on birth control.

Dr. Pinkerman's study was an analysis of a larger ongoing study evaluating the effectiveness of drug and non-drug therapies for frequent, disabling migraines.

The analysis included 107 women prospectively diagnosed with menstrually related migraines according to the International Headache Society's 2004 criteria. All had at least three migraines a month but fewer than 20 headache days per month. None was using preventive medication.

Thirty-five percent were on cyclic birth control medication with 57% of these on combined monophasic low-dose estrogen oral birth control medication. Two women used a ring or transdermal patch contraceptive.

The participants received analgesic, antiemetic and triptan medications. Rescue medications were allowed if triptans failed to relieve the pain, but these were only used in 6.7% of the migraines.

Patients reported an average of 9.1 migraine days per month during the study, which included at least one menstrual cycle during the 43 days of data each woman on average entered in an electronic headache diary. About half of the six headaches a month the women reported were perimenstrual, most of which occurred on the first day of the cycle for both groups.

Migraine features were similar between groups.

Women using birth control used significantly more analgesics: 3.5 pills per migraine versus 2.8 per migraine for those not on birth control (p=0.001). However, women not on birth control used numerically more rescue medication (2.6 doses versus 1.4 doses), but the study was not adequately powered to show a significant difference.

Those who used birth control medication had a significantly higher proportion of their migraines return within 24 hours following a pain-free interval (38.6% versus 22.7%, P=0.026). Menstrually-related migraines were also more likely to recur within 24 hours for women taking birth control (66.0% versus 30.4%), but the study was not sufficiently powered to show significance.

Dr. Pinkerman said the study suggested that women using birth control may have less severe migraines because they were more likely to use analgesics. However, because their migraines are more likely to return, she suggested that they may benefit from a combination of triptans and NSAIDs.

Another option to consider, she said, is using a low-dose continuous birth control medication to reduce the frequency of off-drug periods.

Dr. Pinkerman emphasized that this study should not be construed to discourage oral-contraceptive use.

The triptans in this study were donated by GlaxoSmithKline and Merck.