Table 3 Baseline characteristics and pregnancy outcomes of patients with different COS protocols

Characteristics

N = 362

N = 369

N = 523

P value

Age (years)

29.4 ± 3.7

29.2 ± 3.5

29.1 ± 3.5

0.547

BMI (kg/m²)

25.2 ± 25.6

25.8 ± 33.3

24.1 ± 4.0

0.525

Infertility duration (years)

4.3 ± 2.9

4.0 ± 2.4

4.1 ± 2.6

0.468

AFC

18.1 ± 6.2

25.6 ± 10.8

24.5 ± 9.5

<0.001^a

Basal FSH (IU/L)

6.2 ± 2.5

6.5 ± 1.8

6.5 ± 2.8

0.097

Basal LH (IU/L)

6.0 ± 4.6

7.7 ± 6.3

6.7 ± 4.3

<0.001^b

Basal estrogen (pg/mL)

53.1 ± 124.1

48.0 ± 27.5

65.7 ± 203.4

0.184

Fasting serum glucose (mmol/L)

5.0 ± 0.5

5.1 ± 0.5

5.2 ± 0.8

<0.001^c

Follicles≥14 mm^*

14.1 ± 7.8

17.1 ± 6.9

16.6 ± 7.3

0.176

Days of stimulation

10.3 ± 2.3

12.2 ± 3.2

10.5 ± 3.3

<0.001^d

Gn dosage (IU/L)

2456.1 ± 946.1

2604.1 ± 1233.9

2322.9 ± 1136.9

0.001^e

Serum estrogen (pg/mL) ^*

4854.8 ± 2710.9

3477.0 ± 2266.0

4691.8 ± 3012.0

<0.001^f

Serum Progesterone (ng/mL) ^*

0.9 ± 0.4

0.9 ± 0.7

1.1 ± 0.7

<0.001^g

Serum P/E2 ratio ^*

0.2 ± 0.2

0.4 ± 1.0

0.3 ± 0.4

0.036^h

Endometrial thickness on ET day ^* (cm)

1.0 ± 0.2

1.2 ± 0.3

1.0 ± 0.2

<0.001ⁱ

Oocytes retrieved

15.4 ± 7.0

15.7 ± 7.1

15.8 ± 8.0

0.721

2PN oocytes rate (%)

57.6% (3214/5581)

54.5% (3158/5792)

56.7% (4696/8278)

0.003^j

Cleavage rate of 2PN oocytes (%)

98.1% (3154/3214)

97.2% (3069/3158)

97.9% (4599/4696)

0.023^k

High-quality embryo rate (%)

66.2% (2128/3214)

63.4% (2001/3158)

68.1% (3199/4696)

<0.001^l

Number of embryo transfer cycle

214

204

243

Cycle cancellation rate (%)

40.9%(148/362)

44.7%(165/369)

53.5%(280/523)

0.001^m

Rate of cancelled cycles due to inadequate endometrial thickness (%)

3.4%(5/148)

5.5%(9/165)

9.6%(27/280)

0.036ⁿ

Rate of cancelled cycles due to OHSS prevention (%)

48.0%(71/148)

74.5%(123/165)

56.4%(158/280)

<0.001^o

Rate of cancelled cycles due to high P level (%)^*

4.1%(6/148)

1.8%(3/165)

3.9%(11/280)

0.427

Rate of cancelled cycles due to no embryos obtained (%)

4.1%(6/148)

4.2%(7/165)

4.3%(12/280)

0.471

Rate of cancelled cycles due to no oocytes retrieved (%)

0.7%(1/148)

0.6%(1/165)

0.0%(0/280)

0.405

Rate of cancelled cycles due to other reasons (%)

39.9%(59/148)

13.3%(22/165)

25.7%(72/280)

<0.001^p

Freeze-all cycles rate (%)

39.0%(141/362)

42.5%(157/369)

51.2%(268/523)

0.001^q

Implantation rate (%)

31.6% (132/418)

45.0% (175/389)

22.3% (107/479)

<0.001^r

HCG+ rate (%)

56.5% (121/214)

71.6% (146/204)

52.3% (127/243)

<0.001^s

Clinical pregnancy rate (%)

42.5% (91/214)

62.7% (128/204)

35.4% (86/243)

<0.001^t

Ectopic pregnancy rate (%)

1.4% (3/214)

1.0% (2/204)

2.9% (7/243)

0.279

Early miscarriage rate (%)

3.3% (7/214)

4.4% (9/204)

3.3% (8/243)

0.773

Live birth rate (%)

10.7%(23/214)

25.5%(52/204)

9.8%(24/243)

<0.001^u