Heterogeneity in patient populations explains differences in in vitro fertilization programs.
OBJECTIVE
To evaluate the efficacy of in vitro fertilization and embryo transfer (IVF-ET).


METHODS
Two different models for pregnancy rates in IVF-ET have been developed: a beta-geometric model and a split population model.


METHODS
All IVF cycles were performed at the Yale University School of Medicine in New Haven, Connecticut.


METHODS
All patients undergoing 1,257 IVF-ET cycles performed between the years 1983 through 1987.


METHODS
None.


METHODS
The probability of achieving a viable pregnancy per cycle.


RESULTS
Because both models provide excellent explanations for our data distribution, the decline in the conditional probability of achieving pregnancy after a given number of unsuccessful cycles may be inferred.


CONCLUSIONS
These findings question the justification of continuing IVF-ET treatment beyond some threshold number of cycles.
Hershlag
A
A
Department of Obstetrics and Gynecology, Yale University School of Medicine, New Haven, Connecticut.
Kaplan
E H
EH
Loy
R A
RA
DeCherney
A H
AH
Lavy
G
G
D004624:Embryo Transfer; D005260:Female; D005307:Fertilization in Vitro; D006801:Humans; D008954:Models, Biological; D011247:Pregnancy; D011336:Probability