冷冻膜及冷冻环在人早期胚胎玻璃化冷冻中的应用比较

A comparative study of using the cryotop and cryoloop in vitrification of human preimplantation embryos

目的探讨冷冻膜和冷冻环2种载体行玻璃化冷冻对人卵裂期胚胎和囊胚的效果。方法采用回顾性队列研究分析912个解冻复苏周期,比较2种载体行玻璃化冷冻后胚胎复苏结局和临床结局的差异及其相关危险因素。结果 (1) 385枚卵裂期胚胎中,冷冻环组(n=251)和冷冻膜组(n=134)的胚胎复苏率、完整胚胎存活率、临床妊娠率、种植率、流产率、移植周期出生率、双胎出生率、早产率及出生男女比率差异均无统计学意义(P>0.05);冷冻环组新鲜周期优质胚胎率(24.78%)、平均移植周期数(1.3±0.6)、复苏后优质胚胎率(40.76%)、复苏后平均移植胚胎数[(2.1±0.4)个]及低体质量儿出生率(19.01%)均明显高于冷冻膜组[18.59%,P=0.002;1.2±0.4,P=0.001;28.13%,P=0.001;(1.9±0.4)个,P=0.000;4.08%,P=0.015]。(2) 527枚囊胚中,冷冻环组(n=287)和冷冻膜组(n=240)的平均移植周期数、胚胎复苏率、完整胚胎存活率、复苏后囊胚扩张率、流产率、双胎出生率、早产率、低体质量儿出生率及出生男女比率差异均无统计学意义(P>0.05);冷冻环组的临床妊娠率(67.94%)、种植率(49.72%)、移植周期出生率(52.96%)、新鲜周期优质胚胎率(27.0%)、平均移植胚胎数[(1.9±0.4)个]显著高于冷冻膜组[54.17%, P=0.001;39.58%,P=0.002;41.25%,P=0.047; 23.0%, P=0.002;(1.8±0.5)个,P=0.004]。Logistic回归显示,新鲜周期优质胚胎数、内膜厚度及冷冻胚胎所用载体类型与冷冻囊胚复苏移植后临床妊娠密切相关(P=0.017、P=0.049、P=0.044),而年龄、复苏后平均移植胚胎个数、复苏后囊胚扩张数、平均移植周期数及内膜分型等差异均无统计学意义(P>0.05)。结论对于卵裂期胚胎,冷冻膜和冷冻环冷冻胚胎的复苏结局和临床结局均是相当的。对于囊胚,冷冻环组的临床结局优于冷冻膜组。

Objective To compare the effect of vitrification on human cleaved embryos and blastocysts using cryotop and cryoloop.Method Retrospectively cohort analysis on the documents of 912 frozen embryo transfer (FET) cycles was performed to find out the differences and the potential factors in the embryo developmental and clinical results after vitrification with cryotop and croloop.Results For frozen-thawed cleavage embryos (n=385), no differences were found between the two groups (cryoloop, n=251;cryotop, n=134) in survival rate, fully intact blastomere rate, clinical pregnancy rate, implantation rate, miscarriage rate, delivery rate per transfer, twin birth rate, premature birth rate and ratio of male to female infant. The good-quality embryo rate in fresh (24.78%) and frozen-thawed cycles (40.76%), the number of ET cycles (1.3±0.6), the mean number of frozen-thawed transferred embryos (2.1±0.4) and low birth weight rate (19.01%) in the cryoloop group were significantly higher than those in the cryotop group (18.59%, P=0.002;28.13%, P=0.001;1.2±0.4, P=0.001;1.91±0.41, P=0.000;4.08%, P=0.015). For frozen-thawed blastocysts (n=527), no differences were found between the two groups (cryoloop, n=251;cryotop, n=134) in the number of ET cycles, survival rate, fully intact blastocyst rate, expanded frozen-thawed blastocyst rate, miscarriage rate, twin birth rate, premature birth rate, low birth weight rate and ratio of male to female infants. However, the clinical pregnancy rate (67.94%), the implantation rate (49.72%), the delivery rate per transfer (52.96%), the good-quality embryo rate in fresh cycles (27.0%) and the mean number of frozen-thawed transferred embryos (1.9±0.4) in the cryoloop group were significantly higher than those in the cryotop group (54.17%, P=0.001;39.58%, P=0.002;41.25%, P=0.047;23.0%, P=0.002;1.8±0.5, P=0.004). The further binary logistic analysis confirmed that the number of good-quality embryos in fresh cycles, the type of loading embryos in vitrification (cryoloop or cryotop) and the thickness of endometrium were potential factors of clinical pregnancy in vitrification-thawed blastocysts ET cycles (P=0.017, P=0.049, P=0.044). There were no differences in the age, the mean number of vitrification-thawed transferred embryos, the number of expanded vitrification-thawed blastocyst, the number of ET cycles and the type of endometrium.Conclusion Both vitrification-thawed survival and clinical outcome equal between cryotop and cryoloop in day 3 cleavage embryos cryopreservation embryo-transfer cycles;for blastocyst cryopreservation embryo-transfer cycles, the clinical outcomes in cryoloop group are superior to cryotop group.