Predictive value of embryo grading for embryos with known outcomes.
OBJECTIVE
To compare pronuclear morphology (Z-score), day 3 embryo grade, and day 3 cell number in the prediction of successful implantation rates (IRs), including cycles in which all or none of the embryos implanted.


METHODS
Retrospective analysis.


METHODS
University-based IVF center.


METHODS
Four hundred twenty-six fresh IVF day 3 transfers of 852 embryos in women <36 years of age from January 2000 to December 2003 in whom all or none of the embryos implanted.


METHODS
Evaluation of Z-scores, embryo morphology, cell number, and IR.


RESULTS
Day 3 parameters were more predictive than Z-scores. When early parameters were poor (Z-score) but late parameters were both good, the IR was 38%, compared with 4% when the Z-score was good but the late parameters were poor.


CONCLUSIONS
Embryo grading systems are useful in the prediction of embryo implantation. In particular, cell number and embryo grade are more predictive than Z-scores. Therefore, late parameters have a better prognostic value than Z-scores when selecting embryos for transfer.
Weitzman
Vanessa N
VN
Center for Advanced Reproductive Services, University of Connecticut School of Medicine, Department of Obstetrics and Gynecology, Farmington, Connecticut, USA.
Schnee-Riesz
Jennifer
J
Benadiva
Claudio
C
Nulsen
John
J
Siano
Linda
L
Maier
Donald
D
D000328:Adult; D002455:Cell Division; D010064:Embryo Implantation / Q000502:physiology*; D004622:Embryo, Mammalian / Q000166:cytology / Q000502:physiology*; D047108:Embryonic Development / Q000502:physiology; D005260:Female; D005307:Fertilization in Vitro / Q000706:statistics & numerical data; D006801:Humans; D011237:Predictive Value of Tests; D011247:Pregnancy; D011256:Pregnancy Outcome / Q000453:epidemiology*; D012189:Retrospective Studies