The cytogenetic constitution of embryos derived from immature (metaphase I) oocytes obtained after ovarian hyperstimulation.
OBJECTIVE
To examine the chromosomal content of embryos resulting from metaphase I (MI) oocytes obtained after ovarian hyperstimulation for IVF.


METHODS
Prospective cohort study.


METHODS
University-based IVF Center, Assaf Harofeh Medical Center, Tel Aviv University, Israel.


METHODS
One hundred fifty women undergoing assisted reproduction technique (ART).


METHODS
Intracytoplasmic sperm injection (ICSI) was performed in MI oocytes that were retrieved after ovarian stimulation. A portion of these oocytes extruded their polar body (rescued in vitro-matured metaphase II [IVM-MII]) after different incubation periods and the remainder did not (arrested MI oocytes). Fluorescence in situ hybridization was performed using probes for chromosomes X, Y, 18.


METHODS
Fertilization rate, number of blastomeres, and embryo euploidy.


RESULTS
Embryos from rescued IVM-MII oocytes showed significantly higher fertilization rates and more blastomeres per embryo compared with those from arrested MI oocytes (58.5% vs. 43.9% and 5.7 vs. 5.0, respectively). The chromosomal analysis of these embryos revealed a high rate of aberrations (80.6%), mainly complex mosaics. This rate was elevated in embryos from arrested IVM oocytes (97.2%), and after longer incubation periods. No chromosomally normal embryos were found after 24 hours of incubation of their corresponding oocytes.


CONCLUSIONS
Embryos originating from MI oocytes have a high rate of chromosomal aneuploidy, and their replacement should be reconsidered.
Strassburger
Deborah
D
Infertility and IVF Unit, Assaf Harofeh Medical Center, Zerifin, Israel. embriology@asaf.health.gov.il
Goldstein
Alexandra
A
Friedler
Shevach
S
Raziel
Aryeh
A
Kasterstein
Esti
E
Mashevich
Maya
M
Schachter
Mory
M
Ron-El
Raphael
R
Reish
Orit
O
D000782:Aneuploidy; D002478:Cells, Cultured; D002869:Chromosome Aberrations / Q000196:embryology / Q000706:statistics & numerical data; D002970:Cleavage Stage, Ovum / Q000166:cytology / Q000502:physiology; D020732:Cytogenetic Analysis; D004622:Embryo, Mammalian / Q000166:cytology* / Q000378:metabolism*; D005260:Female; D005306:Fertilization / Q000502:physiology; D006801:Humans; D008297:Male; D008677:Metaphase / Q000235:genetics / Q000502:physiology; D054315:Oocyte Retrieval / Q000379:methods; D009865:Oocytes / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D009866:Oogenesis / Q000235:genetics; D010062:Ovulation Induction; D020554:Sperm Injections, Intracytoplasmic; D013997:Time Factors