单囊胚解冻培养后囊胚腔恢复扩张及孵化程度对临床结局的影响OA

Objectives:To analyze the impact of blastocoel expansion and hatching degree on clinical pregnancy rate. Methods:A retrospective analysis was conducted on 5 941 thawed single-blastocyst transfer cycles treated with replacement cycles at Sichuan Jinxin Xinan Women and Children's Hospital from January 1,2020 to June 30,2023.Blastocysts were classified by post-thaw expansion/hatching into Group Stage Ⅳ(n=867),Group Stage Ⅴ(n=4 839)and Group Stage Ⅵ(n=235).A comparative analysis was conducted on the basic data and pregnancy outcomes of the transplant recipients among the three groups.Further analyses were carried out to examine the differences in clinical pregnancy rate stratified by blastocysts grade(high-quality blastocyst group and lower-quality blastocyst group)and maternal age(≤35 years old group and＞35 years old group).Binary logistic analysis was used to identify the influencing factors of clinical pregnancy. Results:In the comparison of basic data,the female age in Group Stage Ⅳ was significantly higher than that in the other two groups(P＜0.05),and there were statistically significant differences in the duration of embryo culture after thawing among the three groups(P＜0.05),while there were no statistically significant differences in other basic data(P＞0.05).The clinical pregnancy rate(43.48％vs.58.36％vs.53.62％)and live birth rate(34.95％vs.46.58％vs.44.68％)in Group Stage Ⅳ were significantly lower than those in Group Stage Ⅴ and Group Stage Ⅵ(P＜0.016 7),while there were no statistically significant differences in the multiple pregnancy rate,early miscarriage rate and birth defect rate among the three groups(P＞0.016 7).According to the classification based on blastocyst grades,the clinical pregnancy rates of the high-quality blastocyst subgroup and the lower-quality blastocyst subgroup in Group Stage Ⅴ were significantly higher than those in Group Stage Ⅳ.Moreover,the live birth rate of the high-quality blastocyst subgroup in the group Stage Ⅴ was significantly higher than that in Group Stage Ⅳ(P＜0.016 7).Regardless of maternal age,whether it was the group with age≤35 years or the group with age＞35 years,the clinical pregnancy rate and live birth rate in Group Stage Ⅳ were significantly lower than those in Group Stage Ⅴ(P＜0.016 7).The binary logistic regression analysis showed that the age of the female was negatively correlated with the clinical pregnancy rate[OR=0.941,95％CI(0.930,0.953),P＜0.01],and high-quality blastocysts were positively correlated with the clinical pregnancy rate[OR=2.495,95％CI(2.192,2.840),P＜0.01]. Conclusions:After thaw and recovery culture,blastocoel recovery of expansion reaching Stage Ⅴ orⅥ is associated with higher clinical pregnancy and live birth rates in single frozen-thawed blastocyst transfer.