Table 1 Clinical characteristics and oocytes outcomes under the frozen-thawed embryo transfer technology according to female BMIs. Student’s t-tests or Mann-Whitney U-test were applied. Data are presented as mean ± standard error of the mean. The differences were considered statistically significant when the p-value was less than 0.05.

Patiens (n)

2212

320

Age (y)

31.25 ± 0.08

31.57 ± 0.208

0.200

BMI(kg/m²)

21.28 ± 0.04

27.13 ± 0.14

<0.001

Duration of infertility (y)

3.27 ± 0.05

3.51 ± 0.15

0.320

Day3 FSH (IU/L)

5.66 ± 0.03

5.00 ± 0.10

<0.001

Day3 E2 (pg/mL)

33.85 ± 0.29

28.90 ± 0.88

<0.001

Day3 P (ng/mL)

0.29 ± 0.01

0.22 ± 0.01

<0.001

Day3 AFC

11.20 ± 0.09

11.68 ± 0.27

0.150

hMG duration (d)

8.62 ± 0.04

9.44 ± 0.13

<0.001

hMG dose (IU)

1807 ± 9.59

2008 ± 40.05

<0.001

Oocytes retrieved (n)

12.53 ± 0.16

10.98 ± 0.41

<0.001

MII oocytes (n)

7.25 ± 0.12

6.20 ± 0.31

<0.001

Fertilized oocytes (n)

7.02 ± 0.11

6.10 ± 0.30

0.004

Top-quality embryos (n)

3.65 ± 0.07

3.27 ± 0.18

0.018

Viable embryos

4.08 ± 0.07

3.64 ± 0.18

0.004