Detection of fertilization in embryos with accelerated cleavage by fluorescent in-situ hybridization (FISH).
Embryos from a couple undergoing routine in-vitro fertilization for unexplained infertility had shown cleavage by day 1 in two consecutive cycles. The response of the woman to fertility drugs had been normal, and there were no known sperm abnormalities. In a subsequent cycle, accelerated cleavage occurred again and we used a modified method of spreading whole embryos and dual fluorescent in-situ hybridization (FISH) with directly labelled probes for chromosomes X and Y to determine if fertilization had occurred in these embryos. Nine oocytes were collected, five of which had cleaved when examined for pronuclei early on day 1 following late insemination. Pronuclei were observed in one of the remaining oocytes, but in this case, three were present. On day 2, all of the oocytes/embryos had cleaved and two were transferred to the patient. The remaining seven were spread for FISH analysis but nuclei were only obtained from five. In three, a Y signal was detected, indicating that fertilization had occurred. In all five embryos, a wide range of X chromosome signals were observed. These data suggest that the embryos had undergone abnormal fertilization and accelerated cleavage.
Institute of Obstetrics and Gynaecology, Royal Postgraduate Medical School, Hammersmith Hospital, London, UK.
J C
JC
Harper
F
F
Robinson
S
S
Duffy
D K
DK
Griffin
A H
AH
Handyside
J D
JD
Delhanty
R M
RM
Winston
D000328:Adult; D001755:Blastocyst / Q000166:cytology*; D002455:Cell Division; D015342:DNA Probes; D005314:Embryonic and Fetal Development; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D066298:In Vitro Techniques; D007246:Infertility / Q000235:genetics / Q000473:pathology / Q000628:therapy*; D008297:Male; D011247:Pregnancy; D013997:Time Factors; D014960:X Chromosome; D014998:Y Chromosome
D015342:DNA Probes