Human Reproduction, Vol. 4, No. suppl_1, pp. 99-103, 1989
© 1989 European Society of Human Reproduction and Embryology
Cytogenetic analysis and developmental capacity of normal and abnormal embryos after IVF
Unité 173 INSERM, Hôpital Necker-Enfants-Malades 149 rue de Sèvres, 75743, Paris Cedex 15 2 Maternité Guy Le Loner, Hôpital Tenon 4 rue de la Chine, 75020 Paris 3 Service de Gynécologie Obstétrique, Hôpital de Sèvres 141 Grande-Rue, 92310 Sèvres, France
Correspondence: 1To whom correspondence should be addressed
Chromosome abnormalities represent the major cause of pre- and post-implantation embryo wastage. Indeed, 29% of embryos produced by in-vitro fertilization have an abnormal karyotype. Parthenogenesis (1.6% of the cases) and triploidy (6.4%) are the only abnormalities detectable 17 h after insemination. A total of 23% of activated oocytes with a single pronucleus (1 PN) and 18% of fertilized eggs with three pronuclei (three PN) remained uncleaved, compared with 4% for diploid eggs. The rate of cleavage for parthenogenes is not different from normal eggs. On the contrary, we observed that 29% of three PN-eggs reached the 5- to 8-cell stage 42 h after insemination when compared to 15% for diploids mainly due to a direct division of 56% of three PN-eggs in three cells. A model of development for triploid eggs is proposed, taking into account physiological and cytogenetic observations. The quality of embryos expressed in terms of morphology did not show any difference between embryos proceeding from parthenogenes or diploid eggs. On the contrary, the rate of fragmentation is decreased for triploid (3%) compared with diploid (13%) or activated (17%) embryos. Embryos resulting from one, two, three or four pronudeate ova display different developmental capacities during 5 days' culture in vitro.
Key words: chromosome abnormalities/cytogenetics/developmental capacity/human embroys/in-vitro fertilization/polypronuclear stages