Incidence of migraine relative to menstrual cycle phases of rising and falling estrogen.

Objective: To investigate the association between urinary hormone levels and migraine, with particular reference to rising and falling levels of estrogen across the menstrual cycle in women with menstrual and menstrually related migraine.

Methods: Women with regular menstrual cycles, who were not using hormonal contraception or treatments and who experienced between one and four migraine attacks per month, one of which regularly occurred on or between days 1 +/- 2 of menstruation, were studied for three cycles. Women used a fertility monitor to identify ovulation, conducting a test each day as requested by the monitor, using a sample of early morning urine. Urine samples were collected daily for assay of estrone-3-glucuronide, pregnanediol 3-glucuronide, follicle-stimulating hormone, and luteinizing hormone. All women kept a daily migraine diary and continued their usual treatment for migraine.

Results: Of 40 women recruited, data from 38 women were available for analysis. Compared with the expected number of attacks, there was a significantly higher number of migraine attacks during the late luteal/early follicular phase of falling estrogen and lower number of attacks during rising phases of estrogen.

Conclusion: These findings confirm a relationship between migraine and changing levels of estrogen, supporting the hypothesis of perimenstrual but not postovulatory estrogen "withdrawal" migraine. In addition, rising levels of estrogen appear to offer some protection against migraine.