El‐Gharib 2015.

Methods	Randomised controlled trial Duration and location of the trial: quote: "This prospective intervention study was performed during the period from January 2010 till August 2012 at the outpatient clinic of Tanta University Hospital.“
Participants	Inclusion criteria: the most important inclusion criteria were fulfilment of at least 2 of Rotterdam criteria of PCOS, negative history of medical problems that can affect fertility such as diabetes mellitus, thyroid dysfunction, hyperprolactinaemia, congenital adrenal hyperplasia, normal hysterosalpingography and BMI between 20 and 30. Exclusion criteria: history of medical problems which affect fertility, history of recent hormonal therapy, having pelvic infections and/or having abnormal laboratory findings other than PCOS findings. Women whose husbands had defective semen were also excluded. Number of women randomised: 60 participants, 30 in each group Number of women analysed: 60 participants analysed Number of withdrawals/exclusions/loss to follow‐up and reasons: no participants were lost to follow‐up. Number of centres: 1, single‐centre trial Age (y): letrozole 26.2 ± 0.9; tamoxifen 26.9 ± 1.1 BMI (kg/m²): letrozole 27.7 ± 4.1; tamoxifen 28.4 ± 3.8 Duration of infertility (y): letrozole 3.2 ± 2.7; tamoxifen 3.0 ± 2.1 Country: Egypt
Interventions	Group A: letrozole (Femara; Novartis) 2.5 mg/day given from day 5 ‐ 9 of the menstrual cycle, for 3 successive cycles Group B: TMX 20 mg/day given from day 5 ‐ 9 of the menstrual cycle, for 3 successive cycles
Outcomes	Pregnancy rate, follicular growth, endometrial thickness, cumulative ovulation
Notes	Ethical approval: the study was approved by the institutional ethics committee of Tanta Faculty of Medicine. Informed consent: all women subjected to history taking, physical examination, counselling and signing a written consent Source of funding: not reported Power calculation: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Methods of randomisation were not sufficiently described: quote: "arranged at random, by sealed envelopes"
Allocation concealment (selection bias)	Unclear risk	Not reported
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not reported
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not reported
Incomplete outcome data (attrition bias) All outcomes	Low risk	60 participants were randomised and analysed.
Selective reporting (reporting bias)	Low risk	All expected outcomes reported
Other bias	Low risk	None