Embryo morphology or cleavage stage: how to select the best embryos for transfer after in-vitro fertilization

This retrospective study of 1001 in-vitro fertilization (IVF) cycles included a consecutive series of single transfers (n = 341), dual transfers (n = 410) and triple transfers (n = 250) where all the transferred embryos in each cycle were of identical quality score and identical cleavage stage. In o...

Full description

Saved in:
Bibliographic Details
Published in:Human reproduction (Oxford) 1997-07, Vol.12 (7), p.1545-1549
Main Authors: Ziebe, S, Petersen, K, Lindenberg, S, Andersen, A G, Gabrielsen, A, Andersen, A N
Format: Article
Language:English
Subjects:
Adult
Biological and medical sciences
Birth control
Cleavage Stage, Ovum
Embryo Implantation
Embryo Transfer
Embryo, Mammalian - anatomy & histology
Female
Fertilization in Vitro
Gynecology. Andrology. Obstetrics
Humans
Male
Medical sciences
Pregnancy
Pregnancy Outcome
Retrospective Studies
Sterility. Assisted procreation
Citations: Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:This retrospective study of 1001 in-vitro fertilization (IVF) cycles included a consecutive series of single transfers (n = 341), dual transfers (n = 410) and triple transfers (n = 250) where all the transferred embryos in each cycle were of identical quality score and identical cleavage stage. In our 2 day culture system, transfer of 4-cell embryos resulted in a significantly higher implantation rate and pregnancy rate (23 and 49%) compared with 2-cell embryos (12 and 22%) and 3-cell embryos (7 and 15%). Furthermore, the transfer of 4-cell embryos resulted in a significantly higher pregnancy rate compared with embryos that had cleaved beyond the 4-cell stage (28%). The implantation rate (21%) and pregnancy rate (43%) after transfer of embryos of score 1.0 were significantly higher than after transfer of embryos of score 2.0 (14 and 32% respectively). Transferring embryos of score 2.1 resulted in significantly higher implantation rates (26%) and similar pregnancy rates compared with score 1.0. Transferring embryos of score 2.2-3.0 resulted in a significantly lower implantation rate (5%) and pregnancy rate (15%). A striking finding was that embryos of quality score 2.0 had a significantly lower implantation rate compared with embryos of quality score 1.0 and 2.1 and a significantly lower pregnancy rate compared to embryos of quality score 1.0. We also found a lower implantation rate and pregnancy rate when transferring 3-cell embryos. These findings may indicate periods of increased sensitivity to damage during the cell cycle. In conclusion, these results substantiate the idea of the superiority of 4-cell embryos and demonstrate that minor amounts of fragments in the embryo may not be of any importance. These findings may call for a shift when weighing the two main morphological components (quality score and cleavage stage) in the sense that reaching a 4-cell cleavage stage even with the presence of a minor amount of fragments should be preferred to a 2-cell embryo with no fragments.
ISSN:0268-1161
1460-2350
DOI:10.1093/humrep/12.7.1545