Analysis of endometrial thickness threshold and optimal thickness interval in cleavage embryo hormone replacement freeze-thawed embryo transfer (HRT-FET)

Abstract

To investigate the effect of endometrial thickness on the clinical outcome of cleavage embryo HRT-FET on the day of embryo transfer and analyzed the threshold and optimal thickness interval corresponding to ideal clinical pregnancy rate by statistical method. A total of 5861 HRT-FET cycles with cleavage embryo transferred from January 2013 to December 2017 in the Reproductive Medicine Center of Henan Provincial People’s Hospital were studied retrospectively．Fifth-order grouping of endometrial thickness (EMT) on embryo transfer day as a continuous variable by statistical software, they were divided into five subgroups: Q1 (EMT:4.0–7.9 mm), Q2 (EMT: 8.0–8.9 mm), Q3 (EMT: 9.0–9.5 mm), Q4 (EMT: 9. 6–10.9 mm), Q5 (EMT: 11.0–19.0 mm). After adjusting for confounding factors, the clinical pregnancy rate and live birth rate in other groups were higher than Group Q1 significantly (p < .05). The cutoff value of the endometrial thickness was 8.6 mm, When endometrial thickness was less than 8.6 mm, with each additional 1 mm of endometrial thickness, clinical pregnancy rate increased by 49% (OR = 1.49, 95%CI (1.35, 1.66), p < .001), the live birth rate increased by 59% (OR= 1.59, 95%CI (1.42, 1.78), p < .001), When the endometrial thickness was thicker than the threshold, clinical pregnancy rate (OR = 1.02, 95%CI (0.97, 1.07), p = .398) and the live birth rate (OR = 1.00, 95%CI (0.96, 1.05), p = .398) remained stable. In the cleavage embryo HRT-FET cycle, endometrial thickness is a curvilinear relationship with clinical outcome, the optimal endometrial thickness interval for ideal clinical outcome was 8.6–15mm.

摘要

调查胚胎移植当天子宫内膜厚度对卵裂胚胎HRT-FET临床结局的影响, 并对理想临床妊娠率所对应的子宫内膜厚度阈值和最佳厚度区间进行统计学分析。对河南省人民医院生殖医学中心2013年1月至2017年12月共5861个卵裂胚胎移植HRT-FET周期进行回顾性研究, 以胚胎移植日子宫内膜厚度（EMT）为连续变量, 通过统计软件将其分为5个亚组：Q1（EMT：4.0∼7.9 mm）、Q2（EMT：8.0∼8.9 mm）、Q3（EMT：9.0∼9.5 mm）、Q4（EMT：9.6∼10.9 mm）、Q5（EMT：11.0-19.0 mm）。调整混杂因素后, 其他各组的临床妊娠率和活产率均显著高于Q1组（P<0.05）。子宫内膜厚度的临界值为8.6 mm, 当子宫内膜厚度小于8.6 mm时, 每增加1 mm, 临床妊娠率增加49%（OR=1.49, 95%CI（1.35, 1.66）, p<0.001）, 活产率增加59%（OR=1.59, 95%CI（1.42, 1.78）, p<0.001）；当子宫内膜厚度大于临界值时, 临床妊娠率（OR=1.02, 95%CI（0.97, 1.07）, P=0.398）和活产率（OR=1.00, 95%CI（0.96, 1.05）, p=0.398）保持稳定。在卵裂胚胎HRT-FET周期中, 子宫内膜厚度与临床结局呈曲线关系, 理想临床结局的最佳子宫内膜厚度区间为8.6∼15 mm。

Keywords:

• Hormone replacement
• freeze-thawed embryo transfer
• endometrial thickness
• clinical pregnancy rate
• live birth rate

Disclosure statement

The authors declare that they have no competing interests

Acknowledgements

The authors thank everyone at the Reproductive Medical Center of Henan Provincial People’s Hospital for their scientific advice and encouragement.