[Analysis of pregnancy outcomes of D6 single blastocyst transplantation in fresh and frozen-thawed cycles].

ABSTRACT

Objective: To compare the main clinical outcomes of Day 6 (D6) single blastocyst transplantation in fresh and frozen-thawed cycles. Methods: The data of fresh blastocyst transplantation patients and frozen-thawed blastocyst transplantation patients from January 2013 to December 2017 were retrospectively analysed. Fresh blastocyst transplantation and frozen-thawed blastocyst transplantation were matched in a ratio of 1∶3 by using propensity score matching, the matching factors included age, body mass index, thickness of endometrium and blastocyst grade. Totally 180 cases were included in the fresh cycle group and 540 cases in the frozen-thawed cycle group. Results: There was no significant difference in basal FSH between the two groups [(6.9±2.5) versus (6.4±3.8) U/L, P=0.334]. The positive rate of hCG in D6 blastocyst fresh cycle transplantation group [32.8%(59/180) versus 48.1%(260/540)], clinical pregnancy rate [28.9%(52/180) versus 43.5%(235/540)] and live birth rate [21.1%(38/180) versus 32.2%(174/540)] were lower than those of frozen-thawed cycle group (all P<0.05). The miscarriage rate was higher [26.9%(14/52) versus 24.7%(58/235)], but there was no statistical difference (P>0.05). Conclusions: The clinical pregnancy outcome of D6 single blastocyst frozen-thawed cycle transplantation is better than that of fresh cycle. In order to obtain better clinical outcomes, frozen-thawed cycle transplantation of blastocysts formed on the 6th day is recommended.