Table 1 Demographics of study samples by male and female BMI status

Male age (years)

30.21 ± 3.06

30.29 ± 2.98

30.56 ± 2.99*

30.58 ± 2.99*

Female age (years)

29.07 ± 2.93

28.96 ± 3.07

29.47 ± 2.95*

29.36 ± 2.99*

Endometrial thickness (mm)

11.67 ± 2.31

11.85 ± 4.05

11.68 ± 2.74

11.76 ± 3.04

Infertility duration (years)

3.17 ± 1.99

3.48 ± 2.05*

3.19 ± 1.99

3.59 ± 2.12*

E2 on HCG day (mIU/mL)

4814.92 ± 2761.74

3743.38 ± 2391.52*

4706.63 ± 2703.82

3817.43 ± 2450.54*

FSH on HCG day (mIU/mL)

18.13 ± 8.82

14.79 ± 7.29*

17.68 ± 7.87*

14.82 ± 6.18*

P on HCG day (mIU/mL)

1.40 ± 0.78

1.21 ± 0.74

1.69 ± 20.77

1.19 ± 0.68

LH on HCG day (ng/mL)

2.57 ± 44.44

2.76 ± 43.10

6.68 ± 187.17

1.62 ± 1.31

Number of available embryos

6.41 ± 3.88

6.00 ± 3.71*

6.35 ± 3.76

6.03 ± 3.87*

Number of high-quality embryos

3.98 ± 3.13

3.71 ± 3.02*

3.99 ± 3.11

3.77 ± 3.21*

Number of oocytes

12.07 ± 5.59

11.75 ± 5.53

11.94 ± 5.62

11.84 ± 5.79

Number of 2pn

7.58 ± 4.16

7.03 ± 4.00*

7.47 ± 4.01

7.17 ± 4.16*

Number of blastocysts

1.68 ± 2.83

1.75 ± 2.80

1.79 ± 2.81

1.64 ± 2.77

Number of transferred embryos (n, %)

 1

164 (17.58)

81 (18.93)

192 (16.90)

138 (20.78)

 2

769 (82.42)

347 (81.07)

944 (83.10)

526 (79.22)

Number of transferred blastocysts (n, %)

 1

771 (76.04)

341 (76.98)

1005 (77.43)

509 (77.95)

 2

243 (23.96)

102 (23.02)

293 (22.57)

144 (22.05)

Type of embryo transferred (n, %)

 Cleavage stage embryo

933 (47.92)

428 (49.14)

1136 (46.67)

664 (50.42)

 Blastocyst

1014 (52.08)

443 (50.86)

1298 (53.33)

653 (49.58)

Quality o transferred cleavage embryos

 Number of high-quality embryos

1.47 ± 0.50

1.41 ± 0.49

1.42 ± 0.49

1.43 ± 0.50

 Number of available embryos

1.83 ± 0.38

1.81 ± 0.39

1.83 ± 0.37

1.80 ± 0.40

Quality of transferred blastocysts

 Number of high-quality blastocysts

1.03 ± 0.16

1.03 ± 0.17

1.03 ± 0.17

1.04 ± 0.19

 Number of available blastocysts

1.24 ± 0.43

1.23 ± 0.42

1.22 ± 0.42

1.22 ± 0.41

Left testicular volume (mL)

14.30 ± 1.96

14.27 ± 1.86

14.70 ± 2.23*

14.77 ± 2.40*

Right testicular volume (mL)

14.67 ± 20.67

14.29 ± 1.82

14.74 ± 2.20

14.76 ± 2.40

Number of oocytes harvested

12.07 ± 5.59

11.75 ± 5.53

11.94 ± 5.62

11.84 ± 5.79

Technicians title

(Junior/intermediate/senior) (n)

2891/446/71

1204/166/28

3563/564/92

1820/295/51

Smoking (n, %)

585 (17.17)

258 (18.45)

792 (18.77)

411 (18.98)

2015–2019 IVF cycles (n)

604/707/788/921/388

221/268/330/381/198

708/851/930/1187/543

348/424/504/616/274