Preimplantation lethality 2019-04-09T12:33:42Z Preimplantation embryonic lethality Early embryonic arrest It is estimated that about 40-70 percent of human embryos produced in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI) are viable embryos, whereas others arrest at different early stages of development. The phenotype of preimplantation lethality is inferred if IVF and ICSI cycles fail because all of an individual's embryos are arrested at early stages of development. Abnormal preimplantation embryonic development