Abstract: Thirteen trials involving 2914 women were included, of whom 2494 were included in the analysis. Oil-soluble contrast media (OSCM) versus no intervention The OSCM group had a higher rate of live birth (odds ratio (OR) 3.09, 95% CI 1.39 to 6.91, 1 RCT, 158 women, low quality evidence) and ongoing pregnancy (OR 3.59, 95% CI 2.06 to 6.26, 3 RCTs, 382 women, I2 = 0%, low quality evidence) than women who had no intervention. Our findings suggest that among subfertile women with a 17% chance of an ongoing pregnancy if they have no intervention, the rate will increase to between 29% and 55% if they have tubal flushing with OSCM. Water-soluble contrast media (WSCM) versus no intervention There was no evidence of a difference between the groups in rates of live birth (OR 1.13, 95% CI 0.67 to 1.91, 1 RCT, 334 women, very low quality evidence) or ongoing pregnancy (OR 1.14, 95% CI 0.71 to 1.84, 1 RCT, 334 women, very low quality evidence). OSCM versus WSCM Two RCTs reported live birth: one found a higher live birth rate in the oil-soluble group and the other found no evidence of a difference between the groups. These studies were not pooled due to very high heterogeneity (I2 = 93%). There was no evidence of a difference between the groups in rates of ongoing pregnancy, however there was high heterogeneity (OR 1.44, 95% CI 0.84 to 2.47, 5 RCTs, 1454 women, I2 = 76%, random-effects model, very low quality evidence). OSCM plus WSCM versus WSCM alone There was no evidence of a difference between the groups in rates of live birth (OR 1.06, 95% CI 0.64 to 1.77, 1 RCT, 393 women, very low quality evidence) or ongoing pregnancy (OR 1.23, 95% CI 0.87 to 1.72, 4 RCTs, 633 women, I2 = 0%, low quality evidence). There was no evidence of a difference between any of the interventions in rates of adverse events, but such events were poorly reported in most studies. The evidence suggests that tubal flushing with oil-soluble contrast media may increase the chance of pregnancy and live birth compared to no intervention. Findings for other comparisons were inconclusive due to inconsistency and lack of statistical power. There was insufficient evidence on adverse events to reach firm conclusions. Further robust randomised controlled trials are needed.

Plain-language summary: The evidence was current to June 2014. We included randomised controlled trials (RCTs) looking at the effect flushing of the fallopian tubes (with either oil-soluble or water-soluble contrast media) has on live birth and pregnancy rates in women with subfertility. Such women were those who had not been able to conceive after at least six months of unprotected sexual intercourse. We also looked at the rates of adverse events, including miscarriage and ectopic pregnancy (a pregnancy growing outside the womb) after flushing the tubes. We included 13 RCTs (2914 women). The trials compared oil-soluble and water-soluble media with no intervention and with each other. We found evidence that tubal flushing with oil-soluble media may increase the chances of live birth and ongoing pregnancy, compared to no intervention. Our findings suggest that among subfertile women with a 17% chance of ongoing pregnancy if they have no intervention, the rate will increase to between 29% and 55% if they have tubal flushing with oil-based contrast media. We found no evidence of a difference between water-soluble contrast media and no intervention and the contrast media compared one against the other with respect to live birth and pregnancy, though there were few data for most comparisons. There was no evidence of a difference between any of the groups with respect to adverse events, but such events were poorly reported in most studies. The overall quality of the evidence was low or very low for all comparisons. The main limitations were imprecision, risk of bias and inconsistency. There were too few studies to evaluate the risk of publication bias.