P value

Odds ratio (95% CI)

Luteal phase support

<0.001

1.959 (1.331 to 2.884)

Age

0.005

0.944 (0.907 to 0.983)

Body mass index (kg/m²)

0.275

0.964 (0.904 to 1.029)

Day of starting progesterone

Estrogen level (pg/mL)

0.183

1.001 (0.999 to 1.003)

Endometrial thickness (mm)

0.896

1.010 (0.868 to 1.176)

Number of transferred embryos

<0.001

2.012 (1.375 to 2.945)