The FLUSH Trial - Flushing with Lipiodol for unexplained (and endometriosis-related) Subfertility by hysterosalpingography: a randomized trial

BACKGROUND: To assess the effectiveness of flushing with the oil-soluble contrast medium lipiodol in women with unexplained infertility. METHODS: An open randomized controlled trial design in a single centre secondary and tertiary level infertility service setting. A total of 158 women with unexplained infertility were stratified into two populations: 96 women without confirmed endometriosis and 62 women with endometriosis who had normal Fallopian tubes and ovaries. Randomization was computer-generated, with allocation concealment by opaque sequentially numbered envelopes. Lipiodol flushing was tested versus no intervention. The main outcome measures were clinical pregnancy (assessed at 6 months following randomization) and live birth. RESULTS: Lipiodol flushing resulted in a significant increase in pregnancy [48.0 versus 10.8%, relative risk (RR) 4.44, 95% confidence interval (CI) 1.61-12.21] and live birth (40.0 versus 10.8%, RR 3.70, 95% CI 1.30-10.50) rates versus no intervention for women with endometriosis, although there was no significant difference in pregnancy (33.3 versus 20.8%, RR 1.60, 95% CI 0.81-3.16) or live birth (27.1 versus 14.6%, RR 1.86, 95% CI 0.81-4.25) rates for women with unexplained infertility without confirmed endometriosis. CONCLUSIONS: Lipiodol flushing is an effective treatment for couples with unexplained infertility (based on meta-analysis data), but is particularly effective for women with endometriosis who have normal Fallopian tubes and ovaries.