The incidence of abnormal morphology and nucleocytoplasmic ratios in 2-, 3- and 5-day human pre-embryos.
Human cleaving pre-embryos at 2 and 3 days and cavitated pre-embryos at 5 days post-insemination have been examined for cell number and the incidence of mononucleated cells. At least 60% of polynucleate or anucleate cells have been detected at all these stages and regardless of morphological grading at day 2. It is concluded that even by the time at which pre-embryo replacement would occur therapeutically, the majority of pre-embryos are unlikely to have full developmental potential. The possible origins of the abnormalities of nucleocytoplasmic ratios are discussed.
Winston
N J
NJ
Department of Anatomy, University of Cambridge, UK.
Braude
P R
PR
Pickering
S J
SJ
George
M A
MA
Cant
A
A
Currie
J
J
Johnson
M H
MH
D001755:Blastocyst / Q000166:cytology*; D002452:Cell Count; D002455:Cell Division; D002467:Cell Nucleus / Q000648:ultrastructure*; D005314:Embryonic and Fetal Development; D005307:Fertilization in Vitro; D006801:Humans; D066298:In Vitro Techniques; D008856:Microscopy, Fluorescence; D008858:Microscopy, Phase-Contrast