Abstract: This systematic review now has 21 included studies (four of which we added in the 2016 update), two studies awaiting assessment, and 47 excluded studies. In total, data for meta-analyses were available in 21 trials (n = 6218 women), of which only four reported live births. UGET was associated with an increased chance of a live birth/ongoing pregnancy compared with CTET (OR 1.47, 95% CI 1.30 to 1.65; 13 trials; n = 5859 women; I2 = 74%; low-quality evidence). Sensitivity analysis by including only trials with low risk of selection bias or by using a random-effects model did not alter the effect. We estimate that for women with a chance of a live birth/ongoing pregnancy of 23% using CTET, this would increase to between 28% and 33% using UGET. We considered the quality of the evidence using GRADE methodology to be low. UGET was associated with an increase in the chance of a clinical pregnancy (OR 1.31, 95% CI 1.17 to 1.45; 20 trials; n = 6711 women; I2 = 42%; moderate-quality evidence). We identified no differences between groups for the incidence of adverse events including multiple pregnancy, ectopic pregnancy, or miscarriage. These events were relatively rare, and sample sizes limited the ability to detect such differences. The evidence suggests ultrasound guidance improves the chance of live birth/ongoing and clinical pregnancies compared with clinical touch, without increasing the chance of multiple pregnancy, ectopic pregnancy, or miscarriage. Methodological limitations included: only four studies reporting details of both computerised randomisation techniques and adequate allocation concealment, only four studies reported on the outcome of live birth, and none of the nine studies that reported on ongoing pregnancy reported on live birth, suggesting possible reporting bias. Adequate reporting of randomisation and allocation concealment will improve the quality of future studies. The primary outcome measure of future studies should be the reporting of live births per woman randomised.

Plain-language summary: We found 21 randomised controlled trials that compared UGET with clinical touch in a total of 6218 women. The evidence is current to May 2015. Live birth/ongoing pregnancies were increased for the ultrasound-guided group compared with the clinical touch group, based on low-quality evidence. We estimate that for women with a chance of a live birth/ongoing pregnancy of 23% using clinical touch, this would increase to between 28% and 33% using UGET. Data for live birth should be interpreted carefully, as differences between the studies make drawing a conclusion difficult. The evidence suggests that in studies that used the same brand of transfer catheter in both the ultrasound-guided and the clinical touch groups, ultrasound guidance was linked to an increase in the chance of a live birth. There was no evidence that the risk of harm using UGET, including miscarriage, ectopic pregnancies, and multiple pregnancies, is any different than when clinical touch is used to guide the embryo transfer. The quality of the evidence for live birth/ongoing pregnancy was low due to poor reporting of study methods and inconsistency in trial results.