Table 2 Pooled relative risk of having a mild, moderate, or severe migraine on or between day 1 ± 5 days of menstruation and on or between day 1 ± 2 days of menstruation

Severity of migraine1st 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.
Premenstruation
    Mild0.970.63–1.43p = 0.95431.390.78–2.28p = 0.2742
    Moderate1.260.92–1.71p = 0.15581.540.98–2.31p = 0.0657
    Severe1.431.00–2.00p = 0.05582.061.29–3.13p = 0.00355
    All other times1.001.00
Menstruation
    Mild1.621.22–2.12p < 0.001481.541.05–2.19p = 0.0342
    Moderate1.911.52–2.40p < 0.0001661.891.41–2.51p < 0.000162
    Severe2.632.07–3.35p < 0.0001593.412.58–4.47p < 0.000159
    All other times1.001.00