Classification matrices for selected regression models illustrating the prediction accuracy of variables examined either individually or in combination.

a

The percentage of pregnancies correctly classified as a proportion of those blastocysts predicted to result in a successful pregnancy.

b

The percentage of embryos correctly classified as resulting in no pregnancy and pregnancy (the hit ratio).

c

Conventional variables based on the stage and morphological quality code of blastocysts at the time of transfer.

d,e

Different letters indicate a significant difference (P<0.05). Data were analyzed with the Yates' corrected χ2 test.