Nasr 2010

Methods	Randomised, double‐blind, placebo‐controlled pilot study
Participants	Women undergoing unilateral laparoscopic ovarian drilling (LOD) for clomiphene‐resistant PCOS (n = 60) Aged 18 ‐ 38 years; mean age: treatment group 28.4 ± 4.2; placebo group 29.2 ± 3.7, with at least 2 years of infertility due to anovulation, patent fallopian tubes, normal semen analysis Exclusion criteria included no hormonal treatment for 3 months before enrolment and any contraindications to anaesthesia or laparoscopy
Interventions	1. NAC 1.2 grams: 1 sachet a day for 5 days, starting at day 3 of the cycle (immediately after LOD) for 12 consecutive cycles (n = 30) 2. Placebo (n = 30) Both groups also had LOD Follow‐up by cycle monitoring and timed intercourse for a year. No women were lost to follow‐up.
Outcomes	Primary outcome: biochemical pregnancy Secondary outcomes: ovulation, number of follicles, endometrial thickness, clinical pregnancy, miscarriage, multiple pregnancies, ongoing pregnancy, number of preterm deliveries, live birth
Notes	Trial took place in Egypt between January 2005 and June 2007 Ethics obtained. Informed written consent. Endometrial thickness; significant difference in favour of the treatment group Funding source not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomised double‐blind placebo‐controlled pilot study", "computer‐generated random numbers".
Allocation concealment (selection bias)	Unclear risk	"Sealed envelopes".
Blinding (performance bias and detection bias) All outcomes	Low risk	Double‐blind. "The placebo sachets were specially manufactured to look identical to the NAC sachets". "Throughout the study, access to the randomisation code was available only to the pharmacist and was not available to the treating gynaecologist or patients".
Incomplete outcome data (attrition bias) All outcomes	Low risk	No women lost to follow‐up
Selective reporting (reporting bias)	Low risk	All outcomes reported
Other bias	Low risk	No other bias found