Abdelhafeez 2013.

Methods	A randomised controlled trial
Participants	60 women attending the outpatient infertility clinic with a diagnosis of CC‐resistant PCOS at Ain Shams University Maternity Hospital, Cairo, Egypt between February 2010 and September 2010
Interventions	30 women underwent unilateral ovarian drilling and 30 underwent bilateral ovarian drilling
Outcomes	The primary outcome was documented ovulation through a midluteal serum progesterone > 3 ng/ml 3 months after laparoscopy Secondary outcomes included regularity of menstrual cycles and basal levels of serum FSH and LH within 3 months after laparoscopy No harms reported.
Notes	Funding source: Not stated. Declarations of interest: Not stated. Email sent requesting further information.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not stated
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not stated but not possible due to study design
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not stated
Incomplete outcome data (attrition bias) All outcomes	Low risk	No attrition
Selective reporting (reporting bias)	Low risk	All outcomes reported
Other bias	Low risk	None detected