Factors Associated with a Post-Procedure Spontaneous Pregnancy after a Hysterosapingo-Foam-Sonography (HyFoSy): Results from a Multicenter Observational Study.

Background: Tubal patency testing constitutes an essential part of infertility work-up. Hysterosalpingo-foam-sonography (HyFoSy) is currently one of the best tests for assessing tubal patency. The objective of our study was to evaluate the post-procedure rate of spontaneous pregnancy among infertile women submitted for an HyFoSy exam with ExEm foam and the factors associated with this.

Methods: Multicenter, prospective, observational study performed at six Spanish centers for gynecologic sonography and human reproduction. From December 2015 to June 2021, 799 infertile women underwent HyFoSy registration consecutively. The patients' information was collected from their medical records. Multivariable regression analyses were performed, controlling for age, etiology, and time of sterility. The main outcome was to measure post-procedure spontaneous pregnancy rates and the factors associated with the achievement of pregnancy.

Results: 201 (26.5%) women got spontaneous conception (SC group), whereas 557 (73.5%) women did not get pregnant (non-spontaneous conception group, NSC). The median time for reaching SC after HyFoSy was 4 months (CI 95% 3.1-4.9), 18.9% of them occurring the same month of the procedure. Couples with less than 18 months of infertility were 93% more likely to get pregnant after HyFoSy (OR 1.93, 95% CI 1.34-2.81; < 0.001); SC were two times more frequent in women under 35 years with unexplained infertility (OR 2.22, 95% CI 1.07-4.65; P0.033).

Conclusion: After HyFoSy, one in four patients got pregnant within the next twelve months. Couples with shorter infertility time, unexplained infertility, and women under 35 years are more likely to achieve SC after HyFoSy.