Rizk 2005

Methods	Placebo‐controlled, double‐blind, randomised trial
Participants	Women diagnosed with clomiphene citrate‐resistant PCOS (n = 150) aged 18 ‐ 39 years, undergoing therapy for infertility. Timed intercourse. Mean age Treatment group: 28.9 ± 4.7, Placebo group 28.4 ± 5.7. Inclusion criteria: clomiphene citrate‐resistant, at least 1 patent tube, adequate semen analysis according to WHO guidelines, no hormonal treatment Exclusion criteria: hormonal treatment within 2 months of the study, no participants had taken medication to affect carbohydrate metabolism, hyperprolactinaemia, hypercorticism or thyroid dysfunction
Interventions	1. NAC 1.2 g: 1 tablet a day + clomiphene citrate 100 mg: 1 tablet a day for 5 days, starting at day 3 of the cycle for 1 cycle (n = 75) 2. Placebo + clomiphene citrate 100 mg: 1 tablet a day (n = 75)
Outcomes	Ovulation rate Ongoing pregnancy rate, however only pregnancy rate reported Number of follicles of 18 mm Hormone levels Endometrial thickness Ovarian hyperstimulation syndrome (OHSS) Multiple gestations
Notes	Single‐centre university‐based hospital and private infertility practice in Eygpt Trial conducted from March 2002 to November 2003. Informed consent. No mention of funding source Data for miscarriage and multiple pregnancy not in meta‐analysis, as they appear to skew data because of the fact that there were no pregnancies or live birth events in the control group, so no miscarriages. The intervention appears worse in terms of miscarriage when it is simply due to the intervention group having pregnancy and live birth. Emailed author 7th September 2012 regarding the pregnancy rate in the control group and asking for live birth data. Author replied on 10.09.12, confirming that there were no pregnancies in the control group and no live birth data Endometrial thickness; significant difference in favour of the treatment group vs control; see conference abstract
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	"Patients were randomly assigned to receive CC and either NAC or placebo". Method not described
Allocation concealment (selection bias)	Low risk	"Allocation was done by a third party (nurse)". "Using sealed envelopes".
Blinding (performance bias and detection bias) All outcomes	Low risk	"The NAC and placebo were supplied in identical sachets. The patients and the physician monitoring the cycles were blinded to the identity of each medication".
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts were reported
Selective reporting (reporting bias)	Low risk	No known selective reporting
Other bias	Low risk	No other bias found