Many women report migraines in the pill-free interval of combined oral contraceptives, but there is little published information on possible mechanisms and treatments.

The researchers conducted this study to determine whether the use of natural estrogen patches affected the occurrence and severity of migraine during the pill-free interval.

The study design was a double-blind, placebo-controlled, randomized, crossover study. The setting was the City of London Migraine Clinic. The participants were fourteen women with migraines during the pill-free interval.

The interventions were 50 μg oestradiol patches used during the pill-free interval for two cycles versus placebo for two bicycles.

Several pill-free intervals during which migraine occurred; the number of days of migraine; severity of migraine; the number of days of migraine accompanied by nausea, vomiting, and photophobia.

Complete data were available for 12 women and two cycles for one woman. The use of 50 μg estrogen patches during the pill-free interval showed a trend towards reducing migraine frequency and severity.

These results were not as good as expected. However, we had initially aimed for 20 eligible women to participate in the trial, but only 14 were recruited, and only 12 completed the study with full data for analysis.

The results of this pilot study suggest that the use of 50 μg estrogen patches during the pill-free interval may reduce the frequency and severity of migraines at that time. This study should be repeated with larger numbers of women and a higher dose of estrogen.