Table 2 Cycle’s characteristics and oocytes outcomes in the three ovarian stimulation groups according to female BMIs. One-way ANOVA analysis, the nonparametric test, student’s t-tests or Mann-Whitney U-test were applied. Data are presented as mean ± standard error of the mean. The differences were considered statistically significant when the p-value was less than 0.05. When compared with the p-value of subgroups in the same BMI group, the different superscript alphabets of a, b, c stand for a significant difference (p < 0.05). When compared with the p-value of the normal BMI group and high BMI group in the same ovary stimulation group, the symbols *, ^#, ^※ separately stands for a significant difference (p < 0.05) in the conventional short, HMG + MPA (4 mg) and HMG + MPA (10 mg) ovary stimulation group.

Patients (n)

1160

1272

1383

217

226

199

Age (y)

31.29 ± 0.10^a

31.53 ± 0.10^a

31.43 ± 0.10^a

0.222

31.67 ± 0.23^a

32.19 ± 0.26^a,#

31.99 ± 0.26^a,※

0.315

BMI (kg/m²)

21.30 ± 0.05^a

21.35 ± 0.05^a

21.24 ± 0.04^a

0.230

27.20 ± 0.15^a,*

27.38 ± 0.23^a,#

27.29 ± 0.19^a,※

0.787

Duration of infertility (y)

3.28 ± 0.06^a

3.05 ± 0.07^b

3.18 ± 0.07^a,b

0.052

3.82 ± 0.16^a,*

3.39 ± 0.19^a

3.37 ± 0.21^a

0.167

Indication, n (%)

^a

^a

^a

0.447

^a

^a

^a

0.466

Tubal factor

772 (64.9)

817 (61.4)

873 (61.8)

140 (60.3)

147 (61.3)

121 (58.7)

Male factor

91 (7.6)

91 (6.8)

117 (8.3)

26 (11.2)

20 (8.3)

13 (6.3)

Unexplained factor

53 (4.5)

80 (6.0)

69 (4.9)

10 (4.3)

12 (5.0)

15 (7.3)

Combination of factors

274 (23.0)

343 (25.7)

353 (25.0)

56 (24.1)

61 (25.4)

57 (27.7)

Day3 FSH (IU/L)

5.70 ± 0.03^a

5.80 ± 0.04^a

5.80 ± 0.04^a

0.084

5.40 ± 0.09^a,*

5.62 ± 0.08^a,#

5.69 ± 0.10^a

0.063

Day3 E2 (pg/mL)

34.12 ± 0.39^a

35.26 ± 0.36^a

34.89 ± 0.40^a

0.116

30.24 ± 0.89^a,*

32.18 ± 0.81^a,#

32.39 ± 1.04^a,※

0.192

Day3 P (ng/mL)

0.29 ± 0.01^a

0.31 ± 0.01^a

0.31 ± 0.01^a

0.131

0.26 ± 0.02^a

0.25 ± 0.01^a,#

0.27 ± 0.02^a

0.223

Day3 AFC

11.02 ± 0.12^a

11.10 ± 0.12^a

11.07 ± 0.13^a

0.888

11.02 ± 0.31^a

11.23 ± 0.31^a

11.73 ± 0.38^a

0.311

hMG duration (d)

8.14 ± 0.05^a

6.87 ± 0.16^b

8.94 ± 0.04^c

<0.001

9.48 ± 0.19^a,*

7.05 ± 0.27^b

9.44 ± 0.17^a,※

<0.001

hMG dose (IU)

1583 ± 14.09^a

2002 ± 8.60^b

1939 ± 11.30^c

<0.001

1962 ± 59.02^a,*

2171 ± 30.58^b,#

2082 ± 49.26^a,b,※

0.005

Oocytes retrieved (n)

11.03 ± 0.19^a

10.71 ± 0.18^a

11.03 ± 0.16^a

0.360

8.55 ± 0.44^a,*

9.41 ± 0.39^a,#

9.96 ± 0.48^a,※

0.075

MII oocytes (n)

7.68 ± 0.14^a

8.82 ± 0.16^b

8.62 ± 0.15^b

<0.001

5.78 ± 0.32^a,*

8.03 ± 0.36^b

7.68 ± 0.42^b※

<0.001

Fertilized oocytes (n)

7.36 ± 0.14^a,b

7.08 ± 0.14^a

7.68 ± 0.14^b

0.008

5.59 ± 0.31^a,*

6.40 ± 0.31^a

6.59 ± 0.39^a,※

0.083

Top-quality embryos (n)

3.77 ± 0.09^a

2.95 ± 0.09^b

3.68 ± 0.09^a

<0.001

2.81 ± 0.19^a,*

2.62 ± 0.18^a

3.17 ± 0.23^a,※

0.153

Viable embryos (n)

4.40 ± 0.09^a

3.97 ± 0.09^b

4.24 ± 0.09^a,b

0.002

3.38 ± 0.20^a,*

3.59 ± 0.21^a

3.68 ± 0.22^a,※

0.592