Gibreel 2019.

Study characteristics
Methods	Randomised controlled trial, 2 groups, set in Mansoura University Hospital, Egypt April 2014 to April 2015 Number of participants randomised: 210 Number of participants analysed: 210
Participants	Inclusion criteria: women between 20 and 39 years of age; polycystic ovary syndrome (PCOS) as diagnosed by Rotterdam criteria; fertile semen analysis according to World Health Organization (WHO) 2010; bilateral tubal patency as demonstrated by hysterosalpingogram (HSG) Exclusion criteria: suspected endometriosis; suspected uterine cavity anomaly or mass; associated male factor infertility; presence of endocrinopathy as thyroid dysfunction; women subjected to endometrial curettage for any reason in the last 6 months Cause of infertility: anovulatory infertility due to PCOS
Interventions	Intervention group: laparoscopic ovarian drilling (LOD) and endometrial scratching at the end of laparoscopy by endometrial curette Control group: LOD without endometrial scratching Both: all women were seen 3 months after laparoscopy and were asked whether they had a positive pregnancy test, still had oligomenorrhoea, or had regular periods. Women who had regular periods were subjected to folliculometry to confirm the establishment of ovulation; those with oligomenorrhoea were subjected to ovulation induction with clomiphene citrate, tamoxifen, or letrozole. Women who did not respond to ovulatory oral medications were stimulated by exogenous gonadotropins using the low‐dose step‐up protocol, with 37.5 IU as the starting dose Degree of endometrial injury: endometrial curette Timing of endometrial injury: all women underwent LOD immediately after menstrual bleeding (confirmed by author correspondence) Study length: 9 months (confirmed by author correspondence) Type of conception: both timed intercourse (women who started ovulation induction) and intercourse at participants' convenience (women who were ovulatory after LOD) (confirmed by author correspondence)
Outcomes	Reported in the paper: Live birth rate (delivery of a living foetus after 24 weeks' gestation) Clinical pregnancy rate (presence of intrauterine gestational sac 1 or 2 weeks after positive pregnancy test in blood) (reported as outcome in the Methods section but data were not shown in the Results section of the paper) Miscarriage rate (definition provided by author correspondence: total number of women with a positive pregnancy test minus those with live birth as the numerator and the number of women who gave birth as the denominator) Multiple pregnancy rate (reported as outcome in the Methods section but data were not shown in the Results section of the paper)
Notes	Funding source: study authors declared the study was funded by Mansoura University. There was no financial contribution from any pharmaceutical company nor from any other third party Conflicts of interest: study authors declared that they have no competing interests Trial registration: NCT02140398 (prospectively registered) Author correspondence was undertaken
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Quote: "computer‐generated list of random numbers"
Allocation concealment (selection bias)	Low risk	Quote: "opaque sealed envelope" Author correspondence confirmed the envelopes were numbered, ensuring adequate allocation concealment
Blinding of participants (performance bias)	Low risk	Quote: "the surgeon was not blinded to the procedure while patients and data assessor were blinded to their allocation" Quote from author correspondence: "the procedure was done while women were under anesthesia" Therefore it is likely that participants were adequately blinded to the procedure
Blinding of personnel (performance bias)	High risk	Quote: "the surgeon was not blinded to the procedure while patients and data assessor were blinded to their allocation"
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Quote: "the surgeon was not blinded to the procedure while patients and data assessor were blinded to their allocation" Author correspondence confirmed no patient‐reported outcomes were recorded; outcomes were unlikely to be influenced by lack of blinding
Incomplete outcome data (attrition bias) All outcomes	Low risk	Missing outcome data (3 in the scratch group and 2 in the control group) are balanced in numbers across intervention groups, with similar reasons for missing data across groups; therefore the study was rated at low risk of attrition bias
Selective reporting (reporting bias)	Low risk	Trial was registered prospectively. Live birth rate was pre‐specified as the primary outcome and was reported accordingly in the paper. Author correspondence confirmed that multiple pregnancy rate and clinical pregnancy data were incomplete and therefore were not reported in the paper, as not all women had physical follow‐up (i.e. ultrasound). Follow‐up for these women was continued by phone
Other bias	Low risk	We did not identify any other potential sources of bias