Qublan 2009

Methods	Generation of allocation sequence: not reported Allocation concealment method: not reported Blinding method: yes Number and reasons for withdrawals: there were no withdrawals ITT analysis: yes Prospective, randomised, double‐blind, placebo‐controlled trial Metformin versus placebo
Participants	66 clomiphene citrate‐resistant PCOS participants were randomised (34 in the metformin group and 32 in the placebo group) Diagnosis of PCOS followed the Rotterdam criteria (ESHRE/ASRM) 34 women in the metformin group and 32 in the placebo group started controlled ovarian hyperstimulation (66 participants ‐ 4 women in the metformin group and 2 in the placebo group became pregnant spontaneously) There were no withdrawals Infertility factors were reported Both groups were matched for age, cause and duration of infertility, BMI and hormonal/ biochemical profiles All participants were required to have a normal uterine cavity
Interventions	Metformin 850 mg tid for a month before their first ICSI cycle, through the luteal phase and until a positive pregnancy test. If the test was positive metformin was continued until 12 weeks of gestation Protocol for controlled ovarian hyperstimulation: long luteal phase pituitary down‐regulation using the GnRH analogue triptorelin (Decapeptyl®) with human menopausal gonadotropin ‐ HMG (Menogon®) (starting dose of 150 IU daily and adjusted according to ovarian response). Oocyte retrieval was performed within 36 hrs after hCG injection (10000 IU) Assisted reproductive technology (ART): IVF or ICSI Embryo transfer: 2 to 4 embryos were transferred per participant on day 3 after oocyte retrieval Luteal phase support: progesterone pessaries (Cyclogest®)
Outcomes	a) Number of days of gonadotrophins b) Number of ampoules of gonadotrophins c) Number of follicles (> 14 mm) d) Number of mature oocytes e) Fertilisation rate f) Number of embryo transferred g) Pregnancy rate per woman h) Clinical pregnancy rate per woman i) Miscarriage rate j) Serum E2 levels on day of hCG k) Glucose/insulin rate l) Incidence of OHSS
Notes	Country of the study: Jordan
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not stated
Allocation concealment (selection bias)	Unclear risk	Not stated
Blinding (performance bias and detection bias) All outcomes	High risk	Single‐blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	Intention‐to‐treat (ITT) was performed
Selective reporting (reporting bias)	Unclear risk	Live birth rate was not reported
Other bias	Low risk	Power calculation was performed. There were no significant differences in the baseline characteristics of the participants between the 2 groups