Perinatal outcomes of frozen-thawed embryo transfer following blastocyst-stage embryo transfer compared to those of cleavage-stage embryo transfer:analysis of 9408 singleton newborns using propensity score analysis

Objective:Regarding frozen-thawed embryo transfer(FET),there is limited consensus on whether extending embryo culture from the cleavage stage to the blastocyst stage affects perinatal outcomes.This study aimed to compare perinatal outcomes of singletons between blastocyst-stage embryo transfer(BT)and cleavage-stage embryo transfer(CT)in FET.Methods:A total of 9408 FET cycles that met the inclusion criteria were included in this retrospective cohort study between 2019 and 2022.Blastocyst-stage embryo transfers were performed in the BT group,and cleavage-stage embryo transfers were performed in the CT group.Multivariate logistic regression analyses were performed,as well as propensity score matching(PSM)to adjust for confounders.Results:After PSM,a higher risk of pre-term birth(PTB;odds ratio[OR]:1.23,95%confidence interval[CI]:1.00-1.50,P=0.048)and being large for gestational age(LGA;OR:1.16,95%CI:1.00-1.35,P=0.050)was observed in the BT group compared to that in the CT group.After stratified PSM,in the subgroup under 35 years of age,only an increased risk of LGA was observed in the BT group compared to the CT group.Perinatal outcomes in the double-embryo transfer subgroup were similar to those in the unstratified group.However,in the subgroup beyond 35 years of age and the single embryo transfer subgroup,perinatal outcomes were not statistically different between the BT and CT groups(P>0.05).Conclusions:In FET,prolonged embryo culture to the blastocyst stage increased the risk of PTB and LGA in single fetuses.However,stratified analysis based on age and the number of transferred embryos yielded different results,necessitating further mechanistic studies.

Effects of ovarian response prediction index and follicle-oocyte index on pregnancy outcomes:a retrospective cohort study of 12,218 fresh transfer cycles

Objective:To investigate the potential relationships among the ovarian response prediction index(ORPI),follicle-oocyte index(FOI),and clinical pregnancy rate(CPR)in women undergoing their first in vitro fertilization/intracytoplasmic sperm injectionembryo transfer(IVF/ICSI-ET)fresh cycle transfer.Methods:In this retrospective cohort study,we included 12,218 women who underwent their first IVF/ICSI-ET cycle between December 2014 and January 2021.The primary and secondary outcomes of our study were CPR and cumulative live birth rate(CLBR),respectively.The data were divided into three groups according to the ORPI and FOI tertiles.Multivariate logistic regression analyses,stratification analyses,interaction,restricted cubic splines,and receiver operating characteristic(ROC)curves were constructed to identify the relationships among ORPI,FOI,and CPR.Results:A statistically significant increase in CPR was detected from the lowest to the highest tertile group(ORPI:48.12%,54.07%,and 53.47%,P<0.001;FOI:49.99%,52.95%,and 52.71%,P=0.012).A higher CLBR was observed in the high group(ORPI:38.63%,44.62%,and 44.19%,P<0.001;FOI:41.02%,43.78%,and 42.59%,P=0.039).Multivariate logistic regression analysis revealed no statistically significant differences between ORPI,FOI,and neither CPR(odds ratio[OR][95%confidence interval{CI}],0.99[0.97–1.00]vs.[1.02{0.84–1.24}])nor CLBR(OR[95%CI],0.99[0.97–1.01]vs.0.99[0.81–1.20]).No significant association was found among FOI,ORPI,and CPR,even in the subgroups.Restricted cubic spline analyses indicated the existence of a non-linear relationship across the entire range of FOI and ORPI.The ORPI and FOI variables had poor predictive ability(AUC<0.60)for CPR.Conclusions:Both ORPI and FOI are not reliable predictors of clinical pregnancy or live birth outcomes in fresh ETs.Clinicians and researchers should avoid using FOI and ORPI to assess pregnancy outcomes after fresh ET because of their limited relevance and predictive value.