Table 1 Baseline characteristics and clinical outcomes

Cycles

398

1230

297

-

Duration of infertility(years)

3.21 ± 1.98

3.35 ± 2.14

2.97 ± 2.06

0.026

Maternal age (years)

29.17 ± 2.94

29.19 ± 2.84

29.13 ± 2.60

0.939

BMI (kg/m²)

22.24 ± 3.03

22.19 ± 3.09

22.42 ± 2.94

0.500

AFC

16.55 ± 6.42

16.39 ± 6.15

14.79 ± 5.01**

< 0.001

Basal FSH (mIU/ml)

7.27 ± 1.79

7.23 ± 1.69

7.32 ± 1.94

0.685

AMH (ng/ml)

6.47 ± 4.20

6.59 ± 4.00

5.72 ± 3.52**

0.003

Dose of Gn (IU)

2435.31 ± 962.72

2401.90 ± 855.15

2511.15 ± 811.93

0.149

Duration of Gn (days)

11.31 ± 2.01

11.25 ± 2.11

10.99 ± 1.84

0.087

Dose/Duration of Gn (IU/d)

214.10 ± 70.19

213.27 ± 63.17

228.88 ± 64.52**

0.001

E2 (HCG day, pg/ml)

2322.80 ± 1083.71

2289.81 ± 1047.77

2283.90 ± 1065.46

0.849

P (HCG day, ng/ml)

0.72 ± 0.34

0.79 ± 0.52*

0.82 ± 0.34**

0.010

≥ 14 mm follicles

11.92 ± 3.27

11.21 ± 3.17*

9.45 ± 2.95**

< 0.001

Oocytes retrieved

12.74 ± 3.22

12.22 ± 3.35*

11.59 ± 3.29**

< 0.001

Oocyte maturation rate (%)

  IVF

86.10 ± 14.39

88.17 ± 14.22

87.31 ± 14.57

0.101

  ICSI

82.27 ± 14.87

80.59 ± 14.88

81.41 ± 13.05

0.553

Normal fertilisation rate (%)

  IVF

62.70 ± 16.99

63.26 ± 18.53

61.74 ± 19.25

0.525

  ICSI

57.53 ± 19.46

57.78 ± 19.08

55.16 ± 17.80

0.573

Endometrial thickness (mm)

12.26 ± 2.58

12.30 ± 2.58

12.01 ± 2.38

0.223

Frozen blastocysts

3.05 ± 2.35

2.60 ± 2.16*

2.32 ± 2.12**

< 0.001

Blastocyst formation rate (%)

42.38 ± 26.59

38.69 ± 27.16*

38.26 ± 28.27**

0.047

Transfer one embryo

  Clinical pregnancy rate (%)

58.20 (188/323)

65.30 (510/781)

62.82 (98/156)

0.084

Transfer two embryos

  Clinical pregnancy rate (%)

68.00 (51/75)

73.94 (332/449)

67.38 (95/141)

0.232

  Implantation rate (%)

48.67 (73/150)

57.57 (517/898) *

50.71 (143/282)

0.031