A Novel Promising Endometrial Preparation Protocol for Frozen-Thawed Embryo Transfer: A Randomized Controlled Trial

Down-Regulation Ovulation-Induction Leads to Favorable Outcomes in a Single Frozen-Thawed Blastocyst Transfer RCT

Objective

Elective single embryo transfer (eSET) has been increasingly advocated to achieve the goal of delivering a single healthy baby. A novel endometrial preparation approach down-regulation ovulation-induction (DROI) proposed by our team was demonstrated in an RCT that DROI could significantly improve the reproductive outcome compared with modified natural cycle. We aimed to evaluate whether DROI improved clinic pregnancy rate in this single frozen-thawed blastocyst transfer RCT compared with hormone replace treatment (HRT).

Method

Eligible participants were recruited and randomized into one of two endometrial preparation regimens: DROI or HRT between March 15, 2019 and March 12, 2021. The primary outcome was clinical pregnancy rate (CPR). The secondary endpoints included ongoing pregnancy rate (OPR), biochemical miscarriage and first trimester pregnancy loss. This trial is registered at the Chinese Clinical Trial Registry, number ChiCTR2000039804.

Result s

A total of 330 women were randomized in a 1:1 ratio between two groups and 289 women received embryo transfer and completed the study (142 DROI; 147HRT). Pregnancy outcomes were significantly different between the two groups. The CPR and OPR in the DROI group were significantly higher than those of the HRT group (64.08% versus 46.94%, P<0.01; 56.34% versus 38.78%,P<0.01). The biochemical miscarriage and first trimester pregnancy loss were comparable between the two groups.

Conclusion s

The findings of this RCT support the suggestion that the DROI might be a more efficient and promising alternative endometrial preparation approach for FET. Moreover, DROI could play a critical role in promoting uptake of single embryo transfer strategies in FET.

HCG Trigger of GnRH Agonist-Induced Functional Ovarian Cysts Does Not Decrease Clinical Pregnancy Rate in GnRHa Pretreated Frozen Cycles: Evidence From a Retrospective Cohort Study

BACKGROUND

GnRH agonist (GnRHa) pretreatment before the frozen-thawed embryo transfer (FET) was increasingly utilized. However, the incidence of GnRHa-induced functional ovarian cysts (FC) was inevitable. The feasibility and efficacy of HCG triggering GnRHa-induced FC are unknown.

OBJECTIVE

The aim of the study was to investigate the effect of HCG triggering GnRHa-induced FC on FET outcomes.

METHODS

A total of 657 HRT-FET cycles with GnRHa pretreatment were retrospectively analyzed. Patients were divided into the FC group and the no functional cysts (NC) group according to whether the patient developed FC (follicular diameter of ≥7 mm and E₂ of ≥100 pg/ml). Risk factors associated with the incidence of GnRHa-induced FC were determined by multivariate regression analysis. Pregnancy outcomes were compared between the FC group and the NC group. Propensity score matching (PSM) was performed to reduce the impact of confounding factors. Three multivariate regression models were performed to assess the association between HCG triggering GnRHa-induced FC and clinical pregnancy. Interactive analysis and subgroup analysis were also analyzed.

RESULTS

The incidence rate of GnRHa-induced FC was 9.74%. Older age (aOR 1.10, 95% CI 1.05-1.15, p-value < 0.001) and lower BMI (aOR 0.81, 95% CI 0.71-0.93, p-value=0.002) are risk factors for GnRHa-induced FC. The implantation rate, clinical pregnancy rate (CPR), and miscarriage rate were not significantly different between the FC group and the NC group before or after PSM (p-value > 0.05). Multivariate logistic models showed that HCG triggering GnRHa-induced FC does not decrease CPR in the general population (p-value > 0.05). The effect of HCG triggering GnRHa-induced FC on clinical pregnancy is interactive with age (p-value for interaction: 0.003); HCG trigger is associated with significantly higher CPR than HRT-FET cycles without FC in patients ≥35 years (aOR 4.40, 95% CI 1.57-12.3, p-value = 0.005).

CONCLUSIONS

HCG triggering GnRHa-induced FC does not decrease the chance of clinical pregnancy in HRT-FET cycles pretreated with GnRHa.