Table 3 Multivariate regression analysis of the factors associated with live birth

Age (years)

0.919 (0.895, 0.944) per every 1-year increase

 < 0.0001

BMI (kg/m2)

 < 18

1.448 (0.837, 2.503)

0.185

 18 ≤  ~  < 24

reference

 24 ≤  ~  < 28

0.611 (0.364, 1.03)

0.062

 ≥ 28

0.504 (0.31, 0.505)

0.006

Infertility duration (years) (< 1 vs ≥ 1)

1.02 (0.984, 1.058)

0.284

Infertility type (primary vs secondary)

1.039 (0.83, 1.3)

0.74

Infertility cause

 Tubal

reference

 Decreased ovarian deserve

0.791 (0.593, 1.057)

0.113

 Endometriosis

0.624 (0.304, 1.279)

0.198

 Male factors

0.956 (0.678, 1.348)

0.799

 Others

1.120 (0.762, 1.646)

0.564

Endometrium thickness (mm)

1.054 (1.001, 1.109) per every 1-mm increase

0.045

Embryo transfer number (2 vs 1)

2.454 (1.846, 3.261)

0

Embryo stage (blastocyst vs cleavage)

1.362 (0.997, 1.898)

0.082

Embryo quality (good vs poor)

1.035(1.012, 1.081)

0.038

cryopreservation time

0.999 (0.997, 1.000) per every 1-year increase

0.126

LH surge (yes vs no)

0.947 (0.769, 1.166)

0.607