Abstract
ObjectiveTo evaluate the efficacy of the long-acting gonadotropin-releasing hormone agonist (GnRH-a) administration before hormone replacement treatment for frozen-thawed embryo transfer in women with different times of embryo implantation failures.MethodsA retrospective cohort study was performed between January 2015 and December 2019. A total of 9263 women who underwent frozen-thawed embryo transfer were included in the study. The study is divided into three parts based on the times of embryo implantation failures. The sample sizes were 4611 for no implantation failure, 3565 for one failure and 1087 for multiple failures. Two endometrium preparation protocols, HRT and HRT with GnRH-a pretreatment (G-HRT), were compared. Confounding factors were treated by propensity score matching and generalized estimation equation.ResultsFor women with no failure of embryo implantation, the live birth rate was not statistically different when they underwent HRT and G-HRT (HRT: 42.75% [498/1165], G-HRT: 45.24% [527/1165], P=0.2261). Similar outcome also appeared in women with one failure of embryo implantation (HRT: 47.22% [535/1133], G-HRT: 50.31% [570/1131], P=0.1413). For women with multiple failures of embryo implantation, the live birth rate was significantly difference (HRT: 38.74% [117/302], G-HRT: 45.48% [357/785], P=0.0449). When stratified by age, the live birth rate is similar for women older than 37 years. Generalized estimation equation showed that GnRH agonist pretreatment was independently associated with the live birth rate for women with multiple failures (adjust OR: 1.5, 95%CI: [1.12-2.00]).ConclusionFor women with no/one failure of embryo implantation, the live birth rate is similar between HRT and G-HRT protocols. For women with multiple failure of embryo implantation, GnRH agonist pretreatment is beneficial to raise the live birth rate.
Highlights
Frozen-thawed embryo transfer cycles (FETs) have been an important component in the assisted reproduction technology field
BMI, previous conception, scar uterus, tubal factors, number and phase of embryos transferred were significantly different between hormonal replacement treatment cycles (HRTs) and GnRH Agonist Pretreatment (G-HRT) group (P< 0.05) before propensity score matching (PSM)
Days of embryo freezing, BMI, previous conception, scar uterus, number and phase of embryos transferred were different between two group (P< 0.05) for women with one failure of embryo implantation before PSM (Table 2)
Summary
Frozen-thawed embryo transfer cycles (FETs) have been an important component in the assisted reproduction technology field. The Society for Assisted Reproductive Technology (SART) reported an 82.5% increase in the number of FETs, whereas the number of fresh cycles increased only by 3.1% [1]. Studies showed that the transfer of frozen embryos resulted in higher rates of live birth than the transfer of fresh embryos, especially for hyperresponders [3]. Endometrial preparation protocol is an important factor affecting the pregnancy rate of FET, and can mainly be divided into hormonal replacement treatment cycles (HRTs) and natural cycles (NCs). Several studies have shown that GnRH-a suppression significantly enhanced the chances of pregnancy for women with endometriosis or adenomyosis in both fresh and frozen cycles [6, 7]. The mechanism is unclear, but studies have speculated that GnRH-a can improve the endometrial receptivity of these women [8]
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