O-192 Does tubal flushing by hysterosalpingo-foam sonography and hysterosalpingography affect tubal patency? Results from a randomized clinical trial

Abstract Study question Does tubal flushing by hysterosalpingo-foam-sonography (HyFoSy) or hysterosalpingography (HSG) affect tubal patency in infertile women? Summary answer Tubal flushing by HyFoSy and HSG does not increase the number of women with visible bilateral tubal patency. What is known already HyFoSy and HSG are two frequently used methods to visualize tubal patency by flushing a contrast fluid through the Fallopian tubes, while the uterus and Fallopian tubes are imaged using respectively fluoroscopy and ultrasound. Tubal flushing by HSG, specifically with oil-based contrast, improves live birth rates in infertile women. The mechanism of this fertility-enhancing effect is still not completely understood. The potential fertility-enhancing effect of other tubal flushing methods, for example HyFoSy, are studied less frequently. Here, we investigated whether tubal flushing affect tubal patency, and therefore could explain the fertility-enhancing effect of tubal flushing. Study design, size, duration This is a secondary analysis of the FOAM-trial, a multi-center RCT in which women were assigned to undergo tubal flushing by HSG and HyFoSy in randomized order. They either had HyFoSy first and then HSG or the other way around. Here, we assess whether tubal flushing by either HSG or HyFoSy led to differences in tubal patency. We also investigate whether the type of contrast used during HSG (oil -and water based) influenced tubal patency. Participants/materials, setting, methods We studied infertile women with indication for tubal patency testing. Women with anovulatory cycles, endometriosis or with a partner with male infertility were excluded. The main outcome was the number of women with bilateral tubal patency. This outcome, was compared in two analyses: 1) Tubal flushing by HyFoSy versus no flushing, with HSG as reference test, and 2) Tubal flushing by HSG (with oil –or water contrast) versus no flushing, with HyFoSy as reference test. Main results and the role of chance Between May 2015 and January 2019, 1,160 women were included. There were 957 women who underwent HyFoSy with interpretable results and 1,081 women who underwent HSG with interpretable results. Tubal flushing by HyFoSy versus no tubal flushing, with HSG done in all women as reference test, evaluating the effect of tubal flushing by HyFoSy, resulted in a comparable number of women with visible bilateral tubal patency: 467/537 (87%) vs. 472/544 (87%) ; (RR 1.00; 95%CI: 0.96-1.05). Tubal flushing by HSG (with both water –and oil-based contrast) versus no tubal flushing, with HyFoSy done in all women as reference test, evaluating the effect of tubal flushing by HSG, did not show an increase of women with visible bilateral tubal patency: 394/471 (84%) vs. 428/486 (88%); RR 0.95; (95%CI:0.90-1.00). Tubal flushing by HSG with oil-based contrast versus no flushing, with HyFoSy as reference test, resulted in a comparable number of women with visible bilateral tubal patency: 283/330 (86%) vs. 271/308 (88%); RR 0.97; (95%CI:0.92-1.04). Tubal flushing by HSG with water-based contrast versus no flushing, with HyFoSy as reference test, did show a decrease of women with visible bilateral tubal patency: 108/137 (79%) vs. 156/171 (91%); RR 0.90 (95%CI:0.83-0.98). Limitations, reasons for caution It needs to be noted that subtle improvements of tubal patency, caused by initial tubal flushing with either HyFoSy or HSG, cannot be detected on respectively ultrasound and fluoroscopy images and were therefore not assessed in this study. Wider implications of the findings The therapeutic effect of tubal flushing cannot be explained by dissolving visible obstruction in the Fallopian tubes. This suggests that the therapeutic effect of tubal flushing mainly applies to women with anatomically normal Fallopian tubes. Trial registration number NTR4746