Effects of early-cleavage embryo transfer on in vitro fertilization-embryo transfer pregnancy outcomes.

PURPOSE: To observe the effects of early-cleavage embryo transfer (ET) on pregnancy outcomes in vitro fertilization-embryo transfer (IVF-ET). MATERIALS AND METHODS: The data of 6,548 two pro-nucleate (2PN) embryos and 968 patients who underwent IVF or intracytoplasmic sperm injection (ICSI) were analyzed. Of the 968 cycles, early-cleavage embryos were used in 432 cycles (early-cleavage group), late-cleavage embryos were used in 246 cycles (late-cleavage group), and both early and late-cleavage embryos were used in 290 cycles (mixed group). RESULTS: High-quality embryo rate was significantly higher in early-cleavage group than in late-cleavage group (82.74% vs 59.83%; p < 0.01). Both clinical pregnancy and implantation rates in IVF or ICSI were significantly higher in early-cleavage group than in late-cleavage group (all p < 0.01). In ICSI, both clinical pregnancy and implantation rates were significantly higher in mixed group than in late-cleavage group (all p < 0.05). CONCLUSION: Early-cleavage ET can improve pregnancy outcomes in IVF or ICSI.