Cleland 1995.

Study characteristics
Methods	Double‐blind randomised controlled trial, cross‐over design.
Participants	15 female participants with documented catamenial exacerbation of epilepsy. Age, epilepsy duration, and seizure frequency at baseline of participants not reported.
Interventions	6 months of either norethisterone (0.35 mg daily) or placebo treatment, followed by 2‐month wash‐out followed by 6 months of the other treatment; usual medication was continued.
Outcomes	Side effects. Mean menstrual cycle length. Number of seizures outside of "key days". Exacerbation of seizure frequency outside of "key days".
Funding	Not stated.
Conflict of Interest	Not stated.
Notes	Study reported as an abstract only. Very limited information regarding design reported.
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, and a placebo was used.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No information reported.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Inconsistent information throughout the abstract: 5 women studied, 8 out of 14 women had adverse events, but no women withdrew from the study. Unclear how many women were studied.
Selective reporting (reporting bias)	Unclear risk	Insufficient information reported in the abstract to permit a judgement.
Other bias	Unclear risk	Insufficient information reported in the abstract to permit a judgement.