El‐Toukhy 2016.

Methods	RCT Multicenter European centres
Participants	Included women aged < 38 years who had undergone at least two, three, or four fresh IVF or frozen cycles without a pregnancy Normal ultrasound assessment of the uterine cavity At least 8 oocytes retrieved in the previous IVF cycle Exclusion Less than two, or more than four failed IVF cycles ending in an embryo transfer Hysteroscopy less than two months before randomisation Submucous or intramural fibroids diagnosed by ultrasound found to be distorting the uterine cavity Untreated tubal hydrosalpinges BMI > 35 kg/m²
Interventions	Intervention group (N = 350 ) had outpatient hysteroscopy. Hysteroscopy was performed in the early proliferative phase using saline distension medium. intracavitary abnormalities, such as endometrial polyps, septums, and submucosal fibroids were treated. No additional procedure, such as endometrial biopsy, was done All IVF treatments were carried out on the menstrual cycles after office hysteroscopy Control group (N = 352 ) had no hysteroscopy.
Outcomes	Live birth rate, positive pregnancy rate, clinical pregnancy rate, implantation rate, miscarriage rate, normal and abnormal findings of hysteroscopy, adverse events following hysteroscopy
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	"Randomly assigned using independent third party trial management system"
Allocation concealment (selection bias)	Low risk	"Allocation concealment was done to mask the researchers to the order of group assignment at randomisation and recruitment". The minimisation procedure, with a computer‐based algorithm from the integrated trial management system, incorporates allocation concealment.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	While the embryologists were not aware of the allocated group, the physicians performing the embryo transfer were not blinded. However, absence of blinding was unlikely to influence performance bias. Hence, absence of blinding was categorised as low risk for performance bias.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The researchers were not aware of the allocated group. Secondary outcome assessors and physicians were not blinded. Further, absence of blinding was unlikely to influence the findings for our primary and secondary outcomes, hence, categorised as low risk for detection bias.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All randomised participants and losses to follow‐up were mentioned and appeared to be balanced. Intention‐to‐treat analysis was done.
Selective reporting (reporting bias)	Low risk	Published protocol was available. All the prespecified outcomes (including live birth) were reported in the final analysis.
Other bias	Low risk	We found no other potential sources of within‐study bias. Details regarding source of funding and ethical clearance were mentioned.