Dana‐Haeri 1983.

Study characteristics
Methods	Double‐blind randomised controlled trial, cross‐over design.
Participants	9 female participants aged 20 to 30 years with catamenial exacerbation occurring in at least 5 of 12 menstrual cycles were included. Participants were either residents at the Chalfont Centre for Epilepsy or outpatients at the National Hospital, London. Epilepsy duration and seizure frequency at baseline not stated.
Interventions	3 treatment periods, each of 4 menstrual cycles, followed by observation for 1 to 2 months: Low‐dose norethisterone (5 mg 3 times daily as Primolut N tablets). High‐dose norethisterone 350 μg 3 times daily as Micronor tablets. Size‐ and colour‐matched placebo pills. 8 women had been taking either single or combination antiepileptic drug therapy for a long time. 1 woman had discontinued taking carbamazepine and was not taking any antiepileptic drugs.
Outcomes	Seizure frequency during 4 menstrual cycles with each treatment. Results presented separately for women with tonic‐clonic seizures and those with complex partial and simple partial seizures.
Funding	Not stated.
Conflict of Interest	Not stated.
Notes	Unclear if there was a wash‐out period between treatment periods (but very limited information provided on study design, therefore study included despite unclear information about wash‐out period).
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as randomised, but no further information provided.
Allocation concealment (selection bias)	Unclear risk	No information reported.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Study described as double‐blind, size‐ and colour‐matched placebos used.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information reported.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No specific withdrawals reported, but information insufficient to permit a judgement.
Selective reporting (reporting bias)	Unclear risk	No protocol available, outcomes and statistical methods reported in brief. Limited data reported relating to seizures, and adverse events not reported; unclear if any further information was measured but not recorded.
Other bias	Unclear risk	Very limited information provided on study design and participant characteristics. Unclear if there was a wash‐out period between treatment periods. Unclear if any other bias may be present.