The effect of prior hysterosalpingo-foam sonography or hysterosalpingography on tubal patency: a secondary analysis of a randomized controlled trial

Study question: Does hysterosalpingo-foam sonography (HyFoSy) prior to hysterosalpingography (HSG) or HSG prior to HyFoSy affect visible tubal patency when compared HSG or HyFoSy alone?

Summary answer: Undergoing either HyFoSy or HSG prior to tubal patency testing by the alternative method does not demonstrate a significant difference in visible tubal patency when compared to HyFoSy or HSG alone.

What is known already: HyFoSy and HSG are two commonly used visual tubal patency tests with a high and comparable diagnostic accuracy for evaluating tubal patency. These tests may also improve fertility, although the underlying mechanism is still not fully understood. One of the hypotheses points to a dislodgment of mucus plugs that may have disrupted the patency of the Fallopian tubes.

Study design, size, duration: This is a secondary analysis of the randomized controlled FOAM study, in which women underwent tubal patency testing by HyFoSy and HSG, randomized for order of the procedure. Participants either had HyFoSy first and then HSG, or vice versa. Here, we evaluate the relative effectiveness of tubal patency testing by HyFoSy or HSG prior to the alternative tubal patency testing method on visible tubal patency, compared to each method alone.

Participants/materials, setting, methods: Infertile women aged between 18 and 41 years scheduled for tubal patency testing were eligible for participating in the FOAM study. Women with anovulatory cycles, endometriosis, or with a partner with male infertility were excluded. To evaluate the effect HyFoSy on tubal patency, we relied on HSG results by comparing the proportion of women with bilateral tubal patency visible on HSG in those who underwent and who did not undergo HyFoSy prior to their HSG (HyFoSy prior to HSG versus HSG alone). To evaluate the effect of HSG on tubal patency, we relied on HyFoSy results by comparing the proportion of women with bilateral tubal patency visible on HyFoSy in those who underwent and who did not undergo HSG prior to their HyFoSy (HSG prior to HyFoSy versus HyFoSy alone).

Main results and the role of chance: Between May 2015 and January 2019, we randomized 1160 women (576 underwent HyFoSy first followed by HSG, and 584 underwent HSG first followed by HyFoSy). Among the women randomized to HyFoSy prior to HSG, bilateral tubal patency was visible on HSG in 467/537 (87%) women, compared with 472/544 (87%) women who underwent HSG alone (risk difference 0.2%; 95% CI: -3.8% to 4.2%). Among the women randomized to HSG prior to HyFoSy, bilateral tubal patency was visible on HyFoSy in 394/471 (84%) women, compared with 428/486 (88%) women who underwent HyFoSy alone (risk difference -4.4%; 95% CI: -8.8% to 0.0%).

Limitations, reasons for caution: The results of this secondary analysis should be interpreted as exploratory and cannot be regarded as definitive evidence. Furthermore, it has to be noted that pregnancy outcomes were not considered in this analysis.

Wider implications of the findings: Tubal patency testing by either HyFoSy or HSG, prior to the alternative tubal patency testing method does not significantly affect visible tubal patency, when compared to alternative method alone. This suggests that both methods may have comparable abilities to dislodge mucus plugs in the Fallopian tubes.

Study funding/competing interest(s): The FOAM study was an investigator-initiated study, funded by ZonMw, a Dutch organization for Health Research and Development (project number 837001504). IQ Medical Ventures provided the ExEm®-FOAM kits free of charge. The funders had no role in study design, collection, analysis, or interpretation of the data. H.R.V. reports consultancy fees from Ferring. M.v.W. received a travel grant from Oxford University Press in the role of Deputy Editor for Human Reproduction and participates in a Data Safety and Monitoring Board as an independent methodologist in obstetrics studies in which she has no other role. M.v.W. is coordinating editor of Cochrane Fertility and Gynaecology. B.W.J.M. received an investigator grant from NHMRC (GNT1176437) and research funding from Merck KGaA. B.W.J.M. reports consultancy for Organon and Merck KGaA, and travel support from Merck KGaA. B.W.J.M. reports holding stocks of ObsEva. V.M. received research grants from Guerbet, Merck and Ferring and travel and speaker fees from Guerbet. The other authors do not report conflicts of interest.

Trial registration number: International Clinical Trials Registry Platform No. NTR4746.