Lipiodol fertility enhancement: two-year follow-up of a randomized trial suggests a transient benefit in endometriosis, but a sustained benefit in unexplained infertility.

BACKGROUND: A New Zealand randomized trial has shown that lipiodol treatment enhances fertility with high short-term effectiveness for women with endometriosis. METHODS: An open randomized trial in a single-centre secondary- and tertiary-level infertility service assessing lipiodol flushing versus no intervention. A total of 158 women with unexplained infertility (62 women with mild endometriosis and 96 women with pure unexplained infertility) were evaluated at 24 months after trial entry. The main outcome measure was clinical pregnancy, assessed using a Cox proportional hazards regression model. RESULTS: There was a significant benefit in overall pregnancy rate following lipiodol [hazard ratio 2.0, 95% confidence interval (CI) 1.3-3.2]. Among women with endometriosis, the benefit in pregnancy rate seen in the first 6 months following lipiodol (hazard ratio 5.4, 95% CI 2.1-14.2) was not present at 6-24 months (hazard ratio 0.6, 95% CI 0.2-2.1). There was a more consistent effect of lipiodol on fertility throughout the 24-month follow-up among women with unexplained infertility (hazard ratio 2.0, 95% CI 1.1-3.5). CONCLUSIONS: Lipiodol flushing is effective at enhancing fertility not only for women with endometriosis, but also for those with pure unexplained infertility.