Chromosome studies in human in vitro fertilization

The chromosome constitution of 22 human preimplantation embryos from donor oocytes fertilized in vitro by donor sperm was studied to assess the contribution of lethal chromosome anomalies to the high failure rate of implantation of in vitro fertilized embryos after embryo transfer in infertile women. Evidence was found of nondisjunction, resulting in trisomy, monosomy, and nullosomy; structural abnormalities; haploidy; and triploidy. Despite the lethality of their chromosome complements, these embryos could not be distinguished morphologically from those with normal chromosomes.