Fatima 2018.

Methods	RCT Setting: Pakistan Method of randomisation: consecutive non‐probability sampling Blinding: unclear Number randomised: 128
Participants	Summary: metformin and CC versus CC alone Inclusion criteria: PCOS ‐ unclear how diagnosed; duration of fertility ≤ 3 years, age 20‐35 years Exclusion criteria: use of oral contraceptives, comorbid medical conditions, those not living with their husband Baseline characteristics of each group: metformin and CC (n = 64) vs CC (n = 64) mean age (SD) 28.55 (2.39), 28.67 (2.6) Dropouts: none
Interventions	Main intervention: metformin 500 mg 3/d Duration: 3 cycles Co‐interventions: CC 50 mg from day 2 until day 6 of cycle, increased to 100 mg then 150 mg for 3 consecutive cycles
Outcomes	Primary: none Secondary: clinical pregnancy: urine pregnancy test and confirmed on US
Notes	Endocrine and metabolic factors not measured, including BMI
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	High risk	Consecutive non‐probability sampling
Allocation concealment (selection bias)	High risk	Consecutive sampling
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Inadequate information
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Inadequate information
Incomplete outcome data (attrition bias) All outcomes	Low risk	No dropouts
Selective reporting (reporting bias)	Low risk	The primary outcome, clinical pregnancy, was clearly reported.
Other bias	Low risk	No evidence of other bias