Impact of early cleaved zygote morphology on embryo development and in vitro fertilization-embryo transfer outcome: a prospective study.
OBJECTIVE
To evaluate the impact of the first division morphology on embryo development and IVF-embryo transfer outcome.


METHODS
Prospective study.


METHODS
Teaching hospital, France.


METHODS
All zygotes from 201 couples were checked for early cleavage. We defined as "even," early cleaved (EC) zygotes with 2 cells of even size; as "uneven," EC zygotes with 2 cells of uneven size; and as "fragmented," EC zygotes with more than 20% fragmentation rate. Day 2 embryo quality was assessed as "top" embryo or "non-top," with the evaluation of multinucleated blastomeres.


METHODS
None.


METHODS
Day 2 embryo quality, pregnancy and implantation rates.


RESULTS
Among EC zygotes, 59.1% were even, 13.0% were uneven, and 27.9% were fragmented. Even EC yielded more "top" embryos and less multinucleated blastomere embryos than uneven EC (77.0% vs. 46.3%) and fragmented EC (77.0% vs. 13.9%). The 125 double embryo transfers that comprised at least one embryo derived from even EC zygote led to higher pregnancy rate (PR) (64.0% vs. 43.4%) and implantation rate (42.0% vs. 27.6%) compared to the 76 double embryo transfers with embryos derived from breakdown or 2PN zygotes.


CONCLUSIONS
The morphology of the early cleaved zygote is involved in embryo development. Evaluation of this morphology is an effective and valuable method of assessing the embryo quality.
Hesters
Laëtitia
L
APHP, Departments of Biology and Genetics of Reproduction, Antoine Béclère Hospital, Clamart, France. laetitia.hesters@abc.aphp.fr
Prisant
Nadia
N
Fanchin
Renato
R
Méndez Lozano
Daniel H
DH
Feyereisen
Estelle
E
Frydman
René
R
Tachdjian
Gérard
G
Frydman
Nelly
N
D000328:Adult; D002455:Cell Division; D003470:Culture Media; D004624:Embryo Transfer; D047108:Embryonic Development / Q000502:physiology*; D005260:Female; D005306:Fertilization; D005307:Fertilization in Vitro; D006801:Humans; D010062:Ovulation Induction / Q000379:methods; D011247:Pregnancy; D011256:Pregnancy Outcome; D018873:Pregnancy Rate; D011446:Prospective Studies; D015053:Zygote / Q000166:cytology* / Q000502:physiology
D003470:Culture Media