Zhaojuan Hou,1,2 Bin Xu,1,2 Jing Zhao,1,2 Qiong Zhang,1,2 Tianli Yang,1,2 Fen Tian,1,2 Baisheng Wang,3 Yanping Li1,2 

1Department of Reproductive Medicine, Xiangya Hospital, Central South University, Changsha City, Hunan Province, People’s Republic of China; 2Clinical Research Center for Women’s Reproductive Health in Hunan Province, Changsha City, Hunan Province, People’s Republic of China; 3Hunan Key Laboratory of Oral Health Research, Xiangya School of Stomatology, Central South University, Changsha City, Hunan Province, People’s Republic of China

Correspondence: Yanping Li, Department of Reproductive Medicine, Xiangya Hospital, Central South University, Changsha City, Hunan Province, People’s Republic of China, Email liyanp@csu.edu.cn Baisheng Wang, Hunan Key Laboratory of Oral Health Research, Xiangya School of Stomatology, Central South University, Changsha City, Hunan Province, People’s Republic of China, Email baisheng.wang@csu.edu.cn

Objective: This study aimed to investigate whether endometrial thickness (EmT) change prognosticates the ongoing pregnancy rate (OPR) in hormonally prepared frozen-thawed embryo transfers (FETs) in women with treated intrauterine adhesion (IUA).
Methods: We prospectively examined 261 FET cycles in women with IUA. Ultimately, 156 patients were included in the final analysis. The primary outcome was OPR. The association between the EmT change ratio and OPR, as well as the relationship between the EmT change and serum hormone concentration, was analyzed.
Results: The intraclass correlation coefficient for repeated EmT measurements was 0.944 (95% CI: 0.933– 0.954, P < 0.001). Subdividing by the expansion cutoff from 5% to 15%, the 10% expansion group had the highest OPR with optimal sensitivity and specificity. Regarding the baseline characteristics, there were no statistically significant differences between the two groups. Nevertheless, the OPR increased significantly in cycles with endometrial expansion ≥ 10% compared to those with no expansion (55.3% vs 26.3%, P=0.001). The difference was still significant after adjustment between the two groups (adjusted OR, 3.74; 95% CI 1.68– 8.34, P=0.001). No correlation was found between the EmT change and serum hormone concentrations.
Conclusion: Endometrial expansion was significantly correlated with higher OPR in women with treated IUA in the hormonal protocol for FET.

Keywords: endometrial thickness, frozen embryo transfer, intrauterine adhesion, pregnancy outcomes, progesterone