High-quality Cleavage Embryo versus Low-quality Blastocyst in Frozen-thawed Cycles:Comparison of Clinical Outcomes

This study compared the clinical outcomes of the frozen-thawed cycles of high-quality cleavage embryos with low-quality blastocysts to provide a reference for the choice of frozen-thawed embryo transfer schemes and to improve clinical pregnancy rates.A retrospective analysis was performed on the clinical data of patients undergoing frozen-thawed embryo transfer at the Reproductive Medicine Center of Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology from 2016 to 2017.In total,845 cases were divided into a high-quality cleavage embryo group(group A)and a low-quality blastocyst group(group B).Each group was further divided into subgroups based on the number of transplants.Group A was categorized into two subgroups comprising of 94 cases in subgroup Al(1 high-quality 8-cell group)and 201 cases in subgroup A2(2 high-quality 8-cell group).Group B was divided into four subgroups consisting of 73 cases in subgroup B I(D53BC group),65 cases in subgroup B2(D54BC group),110 cases in subgroup B3(D63BC group),and 282 cases in subgroup B4(D64BC group).The pregnancy outcomes and neonatal outcomes between the groups were compared.The clinical pregnancy rates(56.72%and 60.00%)and live birth rates(47.76%and 46.15%)in subgroups A2 and B2 showed no significant differences,but these rates were significantly higher in subgroups A2 and B2 than in the rest subgroups(P<0.05).The multiple birth rate(26.32%)in the subgroup A2 was significantly higher than that in the rest subgroups(P<0.05).There were no statistically significant differences in the abortion rates among all groups(P>0.05).In terms of neonatal outcomes,there were no statistically significant differences in the proportion of premature births,sex ratios,and birth defects among the low-weight and gigantic infants(P>0.05).Transplanting two high-quality cleavage embryos during the frozen-thawed embryo transfer cycles could significantly increase clinical pregnancy rates and live birth rates,but at the same time,it also increased the risks of multiple births and complications to mothers and infants.The D54BC subgroup had the most significant advantages among all groups(P<0.05).The rest low-quality blastocysts had clinical outcomes similar to the single high-quality cleavage embryo group.

Effect of double cleavage stage versus sequential cleavage and blastocyst stage embryo transfer on clinical pregnancy rates

Objective:To compare clinical pregnancy rates following sequential day-3 and day-5 embryo transfer with double or sequential cleavage-stage transfers.Methods:This study enrolled 242 patients undergoing gonadotropin-releasing hormone antagonist protocol and fresh embryo transfer.Basal follicle stimulating hormone,luteinizing hormone,serum estradiol and anti-Müllerian hormone levels and controlled ovarian stimulation outcomes were noted.Of 242 women,135 underwent double embryo transfer on day 2 or day 3(the double group),54 women underwent sequential embryo transfer on day 2 and day 3(the D2/D3 group),and 53 underwent sequential embryo transfer on day 3 and day 5(the D3/D5 group).Clinical pregnancy rates were compared among the groups.Results:Female age,body mass index,basal follicle stimulating hormone,luteinizing hormone and estradiol levels were similar among the groups(P>0.05).The D3/D5 group had a significantly higher number of metaphaseⅡoocytes,fertilized oocytes and good quality embryos on day 3 compared with the double group and the D2/D3 group(P<0.001).Clinical pregnancy rates in the double,D2/D3 and D3/D5 groups were 26.6%(36/135),16.6%(9/54)and 37.7%(20/53),respectively.There was no significant difference in clinical pregnancy rates between the double group and the D2/D3 group(P=0.204)or the D3/D5 group(P=0.188).The D3/D5 group had significantly higher clinical pregnancy rates compared with the D2/D3 group(P=0.025).Conclusions:Sequential cleavage-stage transfer(D2/D3)or cleavage stage and blastocyst transfer(D3/D5)does not improve clinical pregnancy rates compared with double cleavage-stage embryo transfer.Although sequential transfer seems to be an effective option in certain patient populations,routine application of this technique might not be a suitable approach in an unselected population to improve assisted reproductive technology outcomes.