Table 1 Basic characteristics, treatment and outcome parameters in deferent group

N

1942

1192

Age

30.60 ± 3.96

30.62 ± 3.90

0.01 (-0.07, 0.08)

0.868

AMH

3.19 (1.88–5.12)

3.14 (1.93–5.07)

0.04 (-0.03, 0.12)

0.539

BMI

22.55 ± 3.20

22.63 ± 3.35

0.02 (-0.05, 0.10)

0.522

AFC

15.00 (11.00–20.00)

14.00 (10.00–20.00)

0.05 (-0.02, 0.12)

0.208

Duration of infertility

3.00 (2.00–5.00)

3.00 (2.00–4.00)

0.05 (-0.02, 0.13)

0.047

Total days of Gn

11.70 ± 2.36

11.78 ± 4.36

0.02 (-0.05, 0.10)

0.479

Total amount of Gn

2550.00 (1950.00–3150.00)

2625.00 (2000.00–3225.00)

0.05 (-0.02, 0.13)

0.155

E2 on the day of HCG

3795.00 (2458.75–5210.75)

3439.50 (2151.00–4987.00)

0.13 (0.06, 0.20)

 < 0.001

Number of oocytes

14.00 (10.00–18.00)

13.00 (9.00–18.00)

0.13 (0.06, 0.20)

 < 0.001

Number of available embryos

7.00 (4.00–11.00)

7.00 (4.00–10.00)

0.11 (0.03, 0.18)

0.004

Number of 2PN

9.00 (6.00–12.00)

8.00 (5.00–12.00)

0.11 (0.04, 0.19)

 < 0.001

Endometrial thickness on the day of HCG

10.69 ± 1.85

12.10 ± 2.07

0.71 (0.64, 0.79)

 < 0.001

Endometrial thickness on the day of ET

11.84 ± 2.06

10.48 ± 1.74

0.72 (0.64, 0.79)

 < 0.001

Tubal factor infertility

0.03 (-0.05, 0.10)

0.492

 Yes

1551 (79.87%)

964 (80.87%)

 No

391 (20.13%)

228 (19.13%)

Male factor infertility

0.01 (-0.07, 0.08)

0.869

 No

1257 (64.73%)

775 (65.02%)

 Yes

685 (35.27%)

417 (34.98%)

Diminished ovarian reserve

0.01 (-0.06, 0.08)

0.789

 No

1845 (95.01%)

1135 (95.22%)

 Yes

97 (4.99%)

57 (4.78%)

Endometriosis

0.01 (-0.06, 0.08)

0.749

 No

1903 (97.99%)

1170 (98.15%)

 Yes

39 (2.01%)

22 (1.85%)

Unexplained infertility

0.08 (0.01, 0.15)

0.041

 No

1902 (97.94%)

1179 (98.91%)

 Yes

40 (2.06%)

13 (1.09%)

Number of previous ectopic pregnancy

0.07 (-0.01, 0.14)

0.068

 0

1730 (89.64%)

1030 (87.51%)

 ≥ 1

200 (10.36%)

147 (12.49%)

Ectopic pregnancy

0.12 (0.05, 0.19)

0.002

 No

1857 (95.62%)

1165 (97.73%)

 Yes

85 (4.38%)

27 (2.27%)

Number of high-quality embryo transferred

0.00 (-0.07, 0.08)

0.894

 0

285 (14.70%)

173 (14.53%)

 ≥ 1

1654 (85.30%)

1018 (85.47%)

Stage of embryo transferred

0.11 (0.04, 0.18)

0.003

 Cleavage

1219 (62.80%)

811 (68.04%)

 Blastocyst

722 (37.20%)

381 (31.96%)

Number of embryos transferred

0.11 (0.03, 0.18)

0.004

 1

615 (31.67%)

320 (26.85%)

 2

1327 (68.33%)

872 (73.15%)

Ovarian stimulation regimen

0.05 (-0.02, 0.12)

0.382

 Agonist

1406 (72.51%)

870 (72.99%)

 Antagonist

515 (26.56%)

305 (25.59%)

 Other

18 (0.93%)

17 (1.43%)