TUBAL EVALUATION IN THE DIAGNOSTIC EVALUATION OF PATIENTS WITH UNEXPLAINED RECURRENT PREGNANCY LOSS (RPL) UNDERGOING SINGLE, EUPLOID FROZEN EMBRYO TRANSFER (FET): A RETROSPECTIVE COHORT STUDY

OBJECTIVE: In the work-up of RPL, a hysterosalpingography (HSG) or saline sonogram (SIS) can be performed for uterine cavity evaluation. There is no listed role for identifying tubal pathology and it is unclear whether this adds to the evaluation. This study aimed to compare FET outcomes in those with unexplained RPL based on presence of HSG findings. DESIGN: Retrospective cohort study. MATERIALS AND METHODS: First single, euploid FET in 02/2017-06/2024 of patients with unexplained RPL, at an academic-affiliated center were included. Cycles were categorized by cavity evaluation method: (1) SIS-only, or (2) SIS and HSG, stratified by tubal results (normal and abnormal). The primary outcome was sustained implantation rate (SIR, presence of fetal cardiac activity at 8-9 weeks). Secondary outcomes were rate of biochemical pregnancy (bHCG >3 mIU/ml), clinical pregnancy (CPR, presence of a gestational sac), live birth (LBR), and pregnancy loss. Logistic regression models adjusted for oocyte age, body mass index, and embryo day of blastulation. RESULTS: 380 cycles were analyzed: 212 (55.8%) were SIS only and 168 (44.1%) were SIS and HSG. Baseline characteristics were similar except for oocyte age (p = 0.013). Of the cycles with an HSG, 17.3% (29/168) had abnormal tubal findings, including unilateral/bilateral proximal tubal obstruction, patent distal obstruction. One case had a non-patent hydrosalpinx. No cycles had an exploratory laparoscopy prior to first FET. The overall SIR was 65%. There were no differences in SIR, biochemical pregnancy rate, CPR, pregnancy loss rate, and LBR between the groups (Table 1). CONCLUSIONS: In patients with unexplained RPL who underwent an HSG prior to a FET and had tubal pathology present compared to those with normal HSG findings and to those with only a SIS, there was no difference in first single euploid FET outcomes.