Pregnancy and neonatal outcomes of morphologically grade CC blastocysts: are they of clinical value?

Purpose To study if the transfer of morphological grade-CC blastocyst is effective and safe. Methods This retrospective study included 2585 frozen-thawed embryo transfer (FET) cycles with grade-BB blastocysts and 102 FET cycles with grade-CC blastocysts during the period from January 2006 to December 2017. Pregnancy and neonatal outcomes of couples in two groups were analyzed before and after propensity score matching. Results Pregnancy outcomes showed no significant difference in the rates of biochemical pregnancy, ectopic pregnancy, miscarriage, multiple gestation, gestational age ( P > 0.05). However, the rates of intrauterine implantation, clinical pregnancy, and live birth were significantly lower in the grade-CC blastocyst transfer group than those in the grade-BB blastocyst transfer group (18.9% vs 46.0%, 21.6% vs 51.3%, 16.7% vs 41.4%, all P