PMID- 10982037
OWN - NLM
STAT- MEDLINE
DCOM- 20000921
LR  - 20190722
IS  - 0340-6717 (Print)
IS  - 0340-6717 (Linking)
VI  - 107
IP  - 1
DP  - 2000 Jul
TI  - Microscopic assessment of pronuclear embryos is not definitive.
PG  - 62-8
AB  - The microscopic classification of embryos, especially unipronuclear embryos, is 
      not very precise. A number of undocumented and unipronuclear embryos were 
      determined to be diploid following karyotyping and fluorescence in situ 
      hybridization (FISH). Accelerated and asynchronous pronuclear dismantling at the 
      time of checking for embryo fertilization accounts for this disparity. Diploid 
      embryos were also observed among tripronuclear embryos. However, not all embryos 
      ascertained as diploid by FISH were karyotypically normal following full 
      karyotype analysis. By taking into account the "background" abnormality rate, the 
      rate of diploid embryo wastage was estimated to be about 40% among undocumented 
      embryos and about 58% in total. A high percentage of misclassification infers an 
      unintended loss of otherwise transferable embryos. Such a discrepancy is 
      particularly important to older women who have fewer embryos. If these are a 
      woman's only embryos, preimplantation genetic diagnosis might be applicable in 
      determining those that are diploid and suitable for transfer. This could 
      potentially reduce the number of wasted embryos and cycles. The present study has 
      also shown that mosaicism is common but it is still unclear whether mosaicism is 
      indicative of embryonic abnormality or is a fairly common phenomenon among 
      healthy embryos. Bipronuclear embryos that present with abnormal or delayed 
      cleavage are often chaotic in their chromosomal constitution. Such embryos should 
      not be transferred.
FAU - Lim, A S
AU  - Lim AS
AD  - Department of Obstetrics & Gynaecology, Singapore General Hosptal, Singapore. 
      stalvinlim@hotmail.com
FAU - Goh, V H
AU  - Goh VH
FAU - Su, C L
AU  - Su CL
FAU - Yu, S L
AU  - Yu SL
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PL  - Germany
TA  - Hum Genet
JT  - Human genetics
JID - 7613873
SB  - IM
MH  - Adult
MH  - Cell Nucleus/*ultrastructure
MH  - Embryo Disposition
MH  - Embryo Transfer
MH  - Embryo, Mammalian/*ultrastructure
MH  - Female
MH  - Fertilization in Vitro/*methods
MH  - Humans
MH  - In Situ Hybridization, Fluorescence
MH  - Karyotyping/*methods
MH  - Ploidies
MH  - Sperm Injections, Intracytoplasmic/methods
EDAT- 2000/09/12 11:00
MHDA- 2000/09/23 11:01
CRDT- 2000/09/12 11:00
PHST- 2000/09/12 11:00 [pubmed]
PHST- 2000/09/23 11:01 [medline]
PHST- 2000/09/12 11:00 [entrez]
AID - 10.1007/s004390000335 [doi]
PST - ppublish
SO  - Hum Genet. 2000 Jul;107(1):62-8. doi: 10.1007/s004390000335.