Pregnancy outcomes with frozen-thawed single euploid blastocyst transfer following IVF cycles using HCG versus GNRH agonist trigger for final oocyte maturation

Abstract

It is now well known that GnRH agonist (GnRHa) when used to trigger final oocyte maturation results in early luteolysis and consequently luteal phase dysfunction in fresh autologous IVF cycles. However, with the use of adjuvant low dose hCG, pregnancy outcomes are favorable and comparable to after hCG trigger(1). This suggests that GnRHa trigger does not impact oocyte or embryo quality. Furthermore, previous studies have shown comparable live birth rates after frozen-thawed embryo transfer (FET) cycles utilizing embryos obtained from cycles triggered previously with GnRHa versus hCG (2). Previous studies have also shown comparable euploid rates after GnRHa and hCG trigger (3). However, there are no studies evaluating pregnancy rates after transfer of euploid frozen embryos derived from cycles triggered with either GnRHa or hCG trigger. To compare pregnancy outcomes for frozen-thawed single euploid embryo transfer cycles that were generated from cycles triggered with either GnRHa or hCG. Retrospective cohort study done at a single academic IVF center evaluating frozen-thawed embryo transfer (FET) cycles in which single euploid blastocysts were transferred over a four year period. All embryos were generated in preceding fresh autologous IVF cycle in which hCG or GnRHa was used for final oocyte maturation. Embryos were subsequently transferred in a medicated or natural frozen cycle (44.3% medicated cycles in hCG group v. 37.0% in GnRHa group, p>0.05.) Patients were excluded if they had >1 embryo transferred, day 3 embryo biopsies, donor oocyte cycles or dual trigger with both hCG and GnRHa. Primary outcome was ongoing pregnancy rate or live birth rate (OPR/LBR) Secondary outcomes were clinical pregnancy rate (CPR), clinical loss rate (CLR) and multiple pregnancy rate (MPR.) Student’s t-test was used to analyze continuous variables and Chi Square test was used for categorical variables. Multivariate logistical regression was performed to control for potential confounding variables. A p-value of <0.05 was considered statistically significant. A total of 215 FET cycles were included for analysis (hCG trigger, n=115 subjects; GnRHa trigger, n=100 subjects.) The GnRHa group was significantly younger (34.8 years old v. 37.2 years old) and had higher baseline AMH values (4.55 ng/ml versus 2.1 ng/ml) than the hCG group, respectively (p<0.05.) There was no significant difference in OPR/LBR (60.9% v. 62.0%), CPR (68.7% v. 69.0%), CLR (8.9% v. 10.1%) or MPR (1.3% v. 2.9%) in the GnRHa v. hCG groups, respectively. Using logistic regression to control for the significant confounding variables of age and AMH value, the adjusted odds ratio for live birth was 1.09 (95% CI 0.60-1.99, p=0.77) when GnRHa trigger was compared to hCG trigger.Table 1Pregnancy Outcomes After Single Euploid Embryo Transfer in FET cycles Triggered by hCG or GnRHa Stratified by AgeAge Group<35 YO>35 YOAll PatientsPregnancy OutcomehCG (n=29)GnRHa (n=55)hCG (n=86)GnRHa (n=45)hCG (n=115)GnRHa (n=100)IR20/29 (69.0%)41/55 (74.5%)60/86 (69.8%)29/45 (64.4%)80/115 (69.6%)70/100 (70.0%)CPR19/29 (65.5%)41/55 (74.5%)60/86 (69.8%)28/45 (62.2%)79/115 (68.7%)69/100 (69.0%)OPR/LBR16/19 (55.2%)36/55 (65.5%)54/86 (62.8%)26/45 (57.8%)70/115 (60.9%)62/100 (62.0%)CLR3/19 (15.8%)5/41 (12.2%)6/60 (10.0%)2/28 (7.1%)9/79 (8.9%)7/69 (10.1%)MPR1/19 (5.3%)1/41 (2.4%)0/60 (0.0%)1/28 (3.6%)1/79 (1.3%)2/69 (2.9%)∗ There were no significant differences in any of the variables listed above (p>0.05) Open table in a new tab ∗ There were no significant differences in any of the variables listed above (p>0.05) Our findings confirm that euploid embryos created after hCG or GnRHa trigger have the same potential for pregnancy.