The effect of embryo quality on subsequent pregnancy rates after in vitro fertilization.
OBJECTIVE
To determine if a simple morphological classification of embryos was predictive of subsequent pregnancy.


METHODS
Prospective case series.


METHODS
University-based in vitro fertilization (IVF) program.


METHODS
Consecutive embryo transfer (ET) cycles (n = 206).


METHODS
Embryos were classified into three grades: (1) equal-size blastomeres with no fragmentation; (2) unequal-size blastomeres; and (3) evidence of fragmentation.


METHODS
Embryo quality, age, indication for IVF, and stimulation protocol were evaluated for their effect on pregnancy rates (PR's).


RESULTS
In cycles in which the best embryo transferred was grade 3, 2, or 1, the clinical PRs per ET were 0% (0/11 cycles), 12.8% (6/47 cycles, P less than 0.05), and 21.8% (32/148 cycles, P less than 0.05), respectively. When one, two, or three or more grade 1 embryos were replaced, the clinical PRs per ET were 15.6%, 16.3%, and 40% (P less than 0.05), respectively. Using logistic regression, embryo quality (P = 0.0011) and patient's age (P = 0.0044) were the only variables that affected PRs.


CONCLUSIONS
The transfer of more than two good quality embryos had a positive effect, patient's age had a negative effect on PRs after IVF-ET.
Department of Obstetrics and Gynaecology, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
M
M
Erenus
C
C
Zouves
P
P
Rajamahendran
S
S
Leung
M
M
Fluker
V
V
Gomel
D000367:Age Factors; D001757:Blastomeres / Q000502:physiology* / Q000648:ultrastructure; D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D011247:Pregnancy