Table 1 Baseline characteristics of of study participants according to by previous delivery modes

Age (years)

35.05 ± 4.51

35.11 ± 3.97

34.53 ± 4.04

0.552

Infertility duration (years)

4.71 ± 3.60

4.14 ± 3.13

4.14 ± 2.93

0.051

Infertility cause, n(%)

 Tubal factor

199(49.6)

164(45.7)

34(45.9)

0.278

 Ovary factor

46(11.5)

44(12.3)

12(16.2)

 Male factor

60(15.0)

38(10.6)

7(9.5)

 Unexplained

24(6.0)

24(6.7)

4(5.4)

 Combined

72(18.0)

89(24.8)

17(23.0)

Infertility category, n(%)

 Primary

10(2.5%)

11(3.1%)

3(4.1%)

0.744

 Secondary

391(97.5%)

348(96.9%)

71(95.9%)

BMI (kg/m²)

23.21 ± 2.87

23.50 ± 3.11

23.14 ± 2.83

0.347

Basal FSH (IU/L)

7.00 ± 2.45

6.81 ± 2.39

7.39 ± 2.99

0.158

Stimulation protocol, n(%)

 Md-luteal Lupron

252(62.8)

227(63.2)

45(60.8)

0.926

 Antagonist

149(37.2)

132(36.8)

29(39.2)

Total gonadotropins (IU)

2951.35 ± 774.28

2914.25 ± 700.88

2960.51 ± 697.32

0.753

Duration of stimulation (days)

9.23 ± 1.60

9.25 ± 1.60

9.23 ± 1.40

0.990

E₂ level on the trigger day (pg/mL)

3159.21 ± 1928.37

3104.15 ± 1785.13

3127.23 ± 1693.28

0.919

Endometrial thickness on the trigger day (mm)

9.87 ± 1.74

9.72 ± 1.82

9.28 ± 1.50

0.026

Numbers of follicles with a diameter ≥ 14 mm on the day of trigger

10.80 ± 5.27

11.34 ± 5.38

10.76 ± 4.48

0.328

Retrieved oocytes (n)

10.10 ± 5.60

10.72 ± 5.56

10.15 ± 5.01

0.281

Fertilization methods, n(%)

 IVF

266(66.3)

244(68.0)

53(71.6)

0.651

 ICSI

135(33.7)

115(32.0)

21(28.4)

Fertilization rate (%)

76.9(2683/3491)

76.6(2570/787)

77.6(502/647)

0.843

Cleavage rate (%)

98.4(2640/2683)

98.2(2524/2570)

98.6(495/502)

0.767

Available embryos(n)

4(2,6)

4(2,6)

3(2,6)

0.584

High-quality embryos(n)

2(1,4)

2(1,4)

2(1,4)

0.448

Number of embryos transferred (n)

2(1,2)

1(1,2)

1(1,2)

0.087

Day of Transfer, n(%)

 D2

33(8.2%)

19(5.3%)

12(16.2%)

0.005

 D3

368 (91.8%)

340(94.7%)

62(83.8%)

Number of high-quality embryo transferred(n)

1(1,2)

1(1,1)^a

1(1,1)

0.000