Cheong 2017.

Study characteristics
Methods	Unit of randomisation: women Method of randomisation: computer‐generated random numbers in concealed envelopes Time of randomisation: randomised intraoperatively Blinding: women blinded. Assessors at follow‐up blinded.
Participants	Women aged between 18 and 38 years, undergoing gynaecological laparoscopy with possible peri‐ovarian adhesions Exclusion criteria: presence of, or history of malignancy, women on medications affecting ovulation, women with known conditions resulting in anovulation N = 30 15 randomised to intervention and 15 to control Dropouts: None stated. Flow diagram states 17 women randomised to intervention group, however, all other text states 15. Age: mean age 32.7 in intervention group, 31.5 in control Baseline characteristics: states no significant differences Indication for surgery: not clearly stated. States undergoing laparoscopy for gynaecological pathology. Pre‐existing adhesions: all women had peri‐ovarian adhesions and underwent adhesiolysis. Aetiology of pre‐existing adhesions: not stated Microsurgery: principles of microsurgery were followed Additional surgical procedures: not clearly stated, but all women underwent surgery for some form of gynaecological pathology Location: Southampton, UK Timing: December 2011 to January 2014
Interventions	Cross‐linked hyaluronic acid versus no treatment Other adjuvants used: none stated Second‐look laparoscopy not performed
Outcomes	Pregnancy outcomes: Ovarian function Clinical pregnancy rate at 2 years
Notes	Funding provided by Nordic Pharma No power calculation performed ISRCTN Number: ISRCTN1833588
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Computer generated random numbers. The randomisation code was broken at the end of follow‐up period
Allocation concealment (selection bias)	Low risk	Consent was obtained prior to baseline assessment. Concealed, opaque, unlabelled envelopes were opened only after it had been determined that the woman met the intraoperative criteria
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	women were blinded to the allocation treatment, but the primary surgeon was not blinded; women who wished to know their treatment group were informed at the end of follow‐up period.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The assessor who administered the questionnaires and recruited the women was the research nurse who did not have prior knowledge of what type of surgery the women underwent. The assessor during follow‐up was blinded to treatment.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	2 women randomised to Hyalobarrier were lost to follow‐up and were not accounted for; low initial sample number (43 screened, 32 randomised)
Selective reporting (reporting bias)	Low risk	All outcomes stated in clinical trial registry are reported per doi: org/10.1186/ISRCTN18335881
Other bias	Unclear risk	80% of women in intervention group had mild adhesions initially, versus 46.7% in control group. Paper states no difference in severity between the two groups, however, no statistical analysis was provided.