The impact of extended-cycle vaginal ring contraception on migraine aura: a retrospective case series.

OBJECTIVE: To determine whether extended-cycle dosing of an ultralow dose vaginal ring contraceptive decreases frequency of migraine aura and prevents menstrual related migraine (MRM).
BACKGROUND: Many women are denied therapy with combined hormonal contraceptives due to published guidelines that recommend against their use in migraine with aura (MwA). The concern is that these products might further elevate the risk of ischemic stroke that accompanies aura. Stroke risk has been reported to vary directly with aura frequency, and aura frequency in turn has been shown to have a direct relationship to estrogen concentration. With the evolution of increasingly lower dosed combined hormonal contraceptives, we now have formulations that--provided that ovulation is inhibited--result in lower peak levels of estrogen than the concentrations attained during the native menstrual cycle. These formulations would thus be expected to result in a lower frequency of migraine aura. Furthermore, as extended-cycle therapy eliminates monthly estrogen withdrawals, this therapy would likewise be expected to prevent MRM.
METHODS: This pilot study is an institutional review board-approved retrospective database review. We queried our database of 830 women seen in a subspecialty menstrual migraine clinic to identify women who met all inclusion criteria: (1) current history of MwA; (2) confirmed diagnosis of MRM; and (3) treatment with extended-cycle dosing of a transvaginal ring contraceptive containing 0.120 mg etonogestrel/15 µg ethinyl estradiol. Standardized calendars that specifically document bleeding patterns, headache details, and occurrence of aura are required of all patients in this clinic.
RESULTS: Twenty-eight women met study criteria, none of whom were smokers. Of these, 5 discontinued use of etonogestrel/ethinyl estradiol within the first month, leaving 23 evaluable subjects. At baseline, subjects averaged 3.23 migraine auras/month (range: 0.1-12). With extended dosing of the vaginal ring contraceptive, median frequency was reduced to 0.23 auras per month following treatment after a mean observation of 7.8 months (P < .0005). No subject reported an increase in aura frequency. On this regimen, MRM was eliminated in 91.3% of the evaluable subjects.
CONCLUSION: In this sample of women with both MwA and MRM, use of an extended-cycle vaginal ring contraceptive was associated with a reduced frequency of migraine aura and with resolution of MRM. This cannot be extrapolated to suggest that stroke risk in MwA will be similarly reduced. Studies to evaluate this relationship are warranted.