Lazoviz 1998.

Methods	Randomised trial, cross‐over design, data available prior to cross‐over. Study conducted in Institute for Obstetrics and Gynaecology, University of Belgrade, Belgrade, Yugoslavia Timing: not stated.
Participants	56 participants randomised, 6 cycles/patient. Clomiphene‐resistant PCOS participants (high LH). Mean age, duration of infertility, infertility work‐up, mean BMI not stated
Interventions	Ovarian drilling with diathermy or laser vaporisation with CO2 (n = 28), versus Gonadotrophins (FSH or hMG) for ovulation induction for 6 cycles. Number of drill holes per ovary is not stated. (n = 28) Follow‐up for 6 months
Outcomes	Pregnancy rate (by participant), miscarriage rate (by pregnancy), multiple pregnancy rate (by pregnancy)
Notes	Conflict of interest: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No details in paper
Allocation concealment (selection bias)	Unclear risk	No details in paper
Blinding of participants and personnel (performance bias) All outcomes	High risk	No details of blinding, but unlikely to have occurred.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No details
Incomplete outcome data (attrition bias) All outcomes	Low risk	All participants appear to be included in the analysis
Selective reporting (reporting bias)	High risk	This is a conference abstract only. No full paper was identified
Other bias	High risk	Conference abstract