Sorouri 2015.

Methods	Parallel randomised controlled trial. Single centre in Fertility clinic, Al‐Zahara Hospital, Iran Timing: June 2011 to July 2012.
Participants	100 women randomised. Mean age of women in the unilateral group was 27.6 ± 4.3 years and in bilateral group was 28.0 ± 4.3 years Inclusion criteria: Women with PCOS (Rotterdam 2003 criteria) and clomiphene resistance Exclusion criteria: Tubal disease, peritoneal adhesions to tubes or ovaries, endometriosis, endocrine abnormality, concomitant male infertility.
Interventions	Unilateral ovarian drilling (right ovary) (n = 50), versus Bilateral ovarian drilling (n = 50) Unipolar diathermy needle, 8 mm, 60 W and 5 points per ovary Follow‐up for 6 months
Outcomes	Menstrual calender, serum LH and FSH, ovulation, clinical pregnancy
Notes	No conflict of interest Funding from Guilan University of Medical Sciences Clinical trial registration number: not stated
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Blocked sample randomisation, no other details
Allocation concealment (selection bias)	Unclear risk	No details provided
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Surgeons were blinded
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	No details provided
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	45 women in each group were analysed. In the unilateral group 2 women were excluded with tubal disease found during laparoscopy and 3 missed follow‐up visit. In the bilateral group, 1 woman was excluded because of endometriosis found during laparoscopy and 4 were excluded as they missed follow‐up visits
Selective reporting (reporting bias)	Low risk	We found the registered protocol on irct.ir (IRCT138903291306N2). All the outcomes mentioned in the protocol were presented in the published report
Other bias	Low risk	Groups balanced at baseline