A Meta-analysis of clinical efficacy of day 5 and day 6 frozen-thawed blastocyst transfers

Abstract

Objective \nTo systematically evaluate the clinical outcomes of day 5 (D5) and day 6 (D6) frozen-thawed blastocyst transfers. \n \n \nMethods \nThe literatures were searched electronically from the database, including Medline, Cochrane Library, VIN, PubMed, CNKI, Wanfang database. Literatures concerning trials in relation to the comparison of the outcomes of D5 and D6 frozen-thawed blastocyst transfers were searched. The evaluation indicators included live birth rate, clinical pregnancy rate, blastocyst recovery rate, implantation rate and abortion rate. Two evaluators selected the trials according to the inclusion and exclusion criteria, extracted the data and the quality evaluation, then Meta-analysis was conducted by using RevMan5.3 software. \n \n \nResults \nA total of 16 randomized controlled trials were included, involving 13 484 cycles. The results showed that D5 frozen-thawed blastocyst group’s live birth rate (RR=1.25, 95% CI=1.18-1.33), clinical pregnancy rate (RR=1.25, 95% CI=1.14-1.37), and implantation rate (RR=1.38, 95% CI=1.24-1.53) were higher than those in D6 frozen-thawed blastocyst group (P<0.05); the recovery rate of blastocyst was similar in the two groups (RR=1.04, 95% CI=0.99-1.09, P=0.12), while the abortion rate of the D5 frozen-thawed blastocyst group was lower (RR=0.65, 95% CI=0.48-0.87, P=0.004). \n \n \nConclusion \nIt is suggested that the D5 frozen-thawed blastocyst group is superior to the D6 frozen-thawed blastocyst group in terms of live birth rate, clinical pregnancy rate and implantation rate, while the abortion rate is lower. However, the result is limited by the small sample size and quality of the included studies, so more samples and high-quality trials are needed to increase the credibility of the evidence. \n \n \nKey words: \nFrozen-thawed blastocyst transfers;\xa0Pregnancy rate;\xa0Live birth rate;\xa0Meta analysis