Impact of endometrial compaction on pregnancy outcome in patients undergoing frozen-thawed embryo transfer

Banan Abdelhaleem Aboelazm; Emad Abd El Monaem Darwish; Ashraf Haneaa Haneaa Abd El Rahman; Yasser Saad El Kassar

Banan Abdelhaleem Aboelazm Assistant Lecturer of Obstetrics and Gynecology, Department of Obstetrics and Gynecology, Faculty of Medicine, Alexandria University,Egypt
Emad Abd El Monaem Darwish Professor of Obstetrics and Gynecology, Department of Obstetrics and Gynecology, Faculty of Medicine, Alexandria University, Egypt
Ashraf Haneaa Haneaa Abd El Rahman Professor of Obstetrics and Gynecology, Department of Obstetrics and Gynecology, Faculty of Medicine, Alexandria University, Egypt
Yasser Saad El Kassar Assistant Professor of Obstetrics and Gynecology, Department of Obstetrics and Gynecology, Faculty of Medicine, Alexandria University, Egypt

Abstract

Background: For a successful pregnancy to occur, two major components play an important role; a receptive endometrial environment and a good-quality embryo.

Objective: This work aimed to evaluate the impact of endometrial compaction following progesterone administration on pregnancy outcomes in patients undergoing frozen-thawed embryo transfer.

Methods: Prospective observational cohort study at a single IVF Centre, including 307 patients undergoing good-quality vitrified–thawed blastocyst transfer in a hormone replacement therapy (HRT) cycle. The change in endometrial thickness between the end of the estrogen-only phase and the day of embryo transfer, measured using sequential TVUS, was used to categorize endometrium as undergoing compaction (≥5% decrease), no change, or expansion (≥5% increase). The primary outcome measure was the ongoing pregnancy rate.

Results: 25.73% of the cycles showed endometrial compaction, 33.87% showed no EMT change, and 40.39% showed endometrial expansion. The ongoing pregnancy rate was significantly higher in the compaction group compared to the no change and expansion group (48.1% vs. 40.4% vs. 30.6%, respectively; p < 0.039). The clinical pregnancy rate, abortion rate, implantation rate, and chemical pregnancy rate were comparable between the groups. Results were evaluated according to the degree of compaction by dividing the patients into 5% compaction slices. Implantation and ongoing pregnancy rates were significantly higher at a 5-10% compaction level (p = 0.039 and 0.008, respectively).

Conclusion: In patients undergoing HRT–FET, the change in endometrial thickness measured at the end of the estrogen phase and on ET day (endometrial compaction) plays a role in predicting cycle outcome.

Keywords: Endometrial receptivity, Endometrial compaction, Endometrial thickness, HRT, Ongoing pregnancy, Vitrified–thawed embryo transfer.