Table 1 Pooled relative risk of having migraine on or between day 1 ± 5 days of menstruation and on or between day 1 ± 2 days of menstruation

Time of cycle1st day of menstruation ± 5 days1st day of menstruation ± 2 days
Relative risk95% CISignificanceNo. of women*Relative risk95% CISignificanceNo. of women
Premenstruation is the 5 (or 2) days before menstruation; menstruation is the 1st day of bleeding and the subsequent 5 (or 2) days.
* The number of women on whom the relative risk is based.
† “All other times” is defined as the days of the cycle other than day 1 of menstruation ± 5 days.
Premenstruation1.251.10–1.42p < 0.0011501.711.45–2.01p < 0.0001150
Menstruation2.192.01–2.40p < 0.00011552.502.24–2.77p < 0.0001154
All other times1.001.00