Methods	Multicentre, randomised, double-blind, placebo-controlled, parallel-group. Single dose to treat each of 2 attacks occurring −3 to +5 days relative to the first day of menstruation Assessments at 1, 2, and 24 h after dosing Second dose of study medication available to treat recurrence within 24 h Rescue medication (excluding ergotamine-containing preparations or sumatriptan) available if relief was inadequate after 2 h
Participants	Female participants, aged 18 to 50 years, meeting IHS criteria for migraine (1988) without aura. At least 6-month history of migraine occurring −3 to +5 days relative to the first day of menstruation and a history of regular menstrual cycles N = 226 (169 for first dose efficacy assessment with moderate or severe baseline pain intensity) F 226 Mean age 37 years 3% to 6% of subjects with aura (included in efficacy analyses)
Interventions	Sumatriptan 6 mg, n = 115 (77 for first dose efficacy with moderate or severe baseline pain intensity) Placebo, n = 111 (92 for first dose efficacy with moderate or severe baseline pain intensity)
Outcomes	Headache relief (at 1 and 2 h) Pain-free (at 1 and 2 h) Improvement in nausea and photo/phonophobia at 2 h Use of rescue medication Adverse events Withdrawals
Notes	Oxford Quality Score: R2, DB2, W1. Total = 5.
Risk of bias
Bias	Authors’ judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer-generated randomisation scheme
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding (performance bias and detection bias) All outcomes	Low risk	Matching placebo-filled syringes
Study size	Unclear risk	Treatment groups 50 to 200 participants