Frozen-thawed embryo transfer and live birth : long-term follow-up after one oocyte retrieval

Frozen-thawed embryos accounted for 39% (249 of 639) of live births from 931 consecutive first oocyte retrievals after median follow-up of 6.5 years with consistent use of pronuclear-stage freezing and cleavage-stage transfer. Survival after thaw was 95% (2,129 of 2,247). Implantation and live birth rates per individual frozen-thawed embryo transfered were 22% (431 of 1,937) and 18% (346 of 1,937), respectively.