Comparison of clinical outcomes of frozen-thawed blastocysts derived from non-pronucleus or two pronucleus zygotes

Abstract

Objective: To evaluate the application value of the blastocysts derived from non-pronucleus (0PN) zygotes by the good quality blastocyst formation rate and the clinical outcomes of frozen-thawed blastocyst transfers. Methods: The good quality blastocyst formation rate derived from 0PN zygotes was compared with that derived from2 pronucleus (2PN) zygotes in in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) cycles from January 2015 to December 2016. In addition, the clinical pregnancy, embryo implantation and live birth rates of frozen-thawed blastocyst transfers with blastocysts derived from 0PN and 2PN zygotes were analyzed on corresponding dates. Results: (1) In IVF cycles, the high quality blastocysts formation rate of 2PN embryos was significantly higher than that of 0PN (46.64% versus 42.42%, P<0.01) . In ICSI cycles, the high quality blastocysts formation rate of 2PN embryos was markedly higher than that of 0PN (41.96% versus 21.73%, P<0.01) . (2) In frozen-thawed embryo transfer cycles for IVF, the clinical pregnancy, implantation and live birth rates of D5 0PN blastocysts were significantly higher than those of D6 2PN (52.64% versus 46.78%, 49.91% versus 41.20%, 46.54% versus 39.56%, all P<0.05) , however, the abortion and newborn abnormal rates of D5 0PN blastocysts were lower than those of D6 2PN blastocysts (17.37% versus 23.36%, 1.31% versus 4.21%, both P<0.05) ; the clinical pregnancy, implantation and livebirth rates of D5 2PN blastocysts were significantly higher than those of D5 0PN (59.73% versus 52.64%, 55.95% versus 49.91%, 53.03% versus 46.54%, all P<0.05) , but newborn abnormal rate was a little higher than that of D5 0PN (3.90% versus 1.31%, P<0.05) ; the clinical pregnancy, implantation and live birth rates of D5 2PN blastocysts were significantly higher than those of D6 2PN (59.73% versus 46.78%, 55.95% versus 41.20%, 53.03% versus 39.56%, all P<0.05) , and the abortion rate of D5 2PN blastocysts was lower than that of D6 2PN blastocysts (18.23% versus 23.36%, P<0.05) . Conclusions: Although the blastocysts derived from 0PN could be transffered, the blastocysts derived from 2PN zygotes are preferred in all cycles. In IVF cycles, the good quality blastocysts derived from 2PN or 0PN zygotes will be transferred.