IMPACT OF ENDOMETRIOSIS ON UTERINE PERISTALSIS AND SERUM CONCENTRATIONS OF PROGESTERONE IN PATIENTS WITH RECURRENT IMPLANTATION FAILURE UNDERGOING FROZEN-THAWED EMBRYO TRANSFER

Problem statement
Uterine quiescency during secretory phase plays an important role during embryo implantation, and it is due to the progesterone effect. However, supraphysiological levels of estradiol associated to endometriosis may produce progesterone resistance. In addition, this effect seems to produce increased expression of oxytocin receptors, which it is thought lead to increased uterine peristalsis frequency. The aim of the study is to analyze the putative relationship of uterine peristalsis and serum concentrations of progesterone in patients with endometriosis and recurrent implantation failure.
Methods
A retrospective cohort study has been carried out from 2017 to 2022 including 571 patients diagnosed with recurrent implantation failure (RIF) undergoing frozen-thawed blastocyst embryo transfer.198 (34,7%) patients were diagnosed of endometriosis. Uterine peristalsis has been assessed using 2D/4D ultrasound for 6 minutes the day of embryo transfer and it has been defined as contractions per minute (cpm). Progesterone assessment was performed the day of embryo transfer.
Results
Patients with endometriosis were younger (40,1± 4,7 vs 41,1±4,4; p=0,012), performed more treatments (3,9±2,7 vs 3,2±2,2; p=0,003) and suffered more miscarriages (1,02±1,5 vs 0,8±1; p=0,046) in comparison with RIF only patients. Also, there were statistically significant differences between groups in the presence of fibroids, intrauterine adhesions, and uterine malformations, so multivariate logistic regression analysis was done adjusted by these factors. Uterine peristalsis was found increased in endometriosis respect to RIF patients (1,3 ±0,8 cpm vs 1,1±0,7 cpm; OR 1,4; 95%IC 1,1 to 1,8; p= 0,006). Serum concentration of progesterone was lower in endometriosis in comparison to RIF patients (18±13 ng/ml vs 22,2±14 ng/ml; OR 0,98; 95% 0,96 to 0,99; p=0,001).
Conclusion
Patients suffering from endometriosis and recurrent implantation failure show poor prognosis. It could be mediated by lower levels of progesterone driving to higher uterine peristalsis frequency. Confirmation of these findings could lead to the development of strategies to address this situation.