Table 1 Characteristics of participants in different BMI categories

N

1180 (9.3)

9134 (71.9)

2097 (16.5)

301 (2.4)

Age(years)

30 (28–32)^b

31 (29–34)^c

32 (29–35)^d

31 (29–34)^cd

  < 35

1020 (86.4)^b

6852 (75.0)^c

1501 (71.6)^d

232 (77.1)^cd

  ≥ 35

160 (13.6)^b

2282 (25.0)^c

596 (28.4)^d

69 (22.9)^cd

Height(cm)

162.0 (160.0–165.0)^b

162.0 (159.0–165.0)^c

162.0 (159.0–165.0)^c

162.0 (160.0–165.0)^bc

Pre-pregnancy Weight(kg)

46.0 (44.0–49.0)^b

56.5 (52.5–60.0)^c

70.0 (66.0–74.0)^d

84.0 (79.5–90.0)^e

Pre-pregnancy BMI(kg/m²)

17.7 (17.0–18.1)^b

21.6 (20.2–23.0)^c

26.4 (25.6–27.6)^d

31.4 (30.5–33.3)^e

Education level

 Low

140 (11.9)^b

1204 (13.2)^b

365 (17.4)^c

64 (21.3)^c

 Medium

832 (70.5)^b

6387 (69.9)^b

1473 (70.2)^b

214 (71.1)^b

 High

194 (16.4)^b

1415 (15.5)^b

231 (11.0)^c

20 (6.6)^c

 Missing

14 (1.2)^b

128 (1.4)^b

28 (1.3)^b

3 (1.0)^b

Oral glucose tolerance test

 Fasting plasma glucose level(mmol/L)

5.11 (4.66–5.30)^b

5.19 (4.88–5.40)^c

5.29 (5.10–5.56)^d

5.32 (5.13–5.58)^d

 1 h plasma glucose level(mmol/L)

9.05 ± 1.78^b

9.24 ± 1.73^c

9.64 ± 1.80^d

9.79 ± 1.69^d

 2 h plasma glucose level(mmol/L)

7.89 ± 1.48^b

7.96 ± 1.48^b

8.07 ± 1.52^c

7.78 ± 1.50^b

History of adverse pregnancy

473 (40.1)^b

4495 (49.2)^c

1092 (52.1)^c

154 (51.2)^c

History of previous cesarean section

131 (11.1)^b

1550 (17.0)^c

474 (22.6)^d

65 (21.6)^cd

Parity

 Nulliparous

859 (72.8)^b

5583 (61.1)^c

1207 (57.6)^d

180 (59.8)^cd

 Multiparous

321 (27.2)^b

3551 (38.9)^c

890 (42.4)^d

121 (40.2)^cd

Family history of diabetes

95 (8.1)^b

875 (9.6)^b

241 (11.5)^c

51 (16.9)^d

Family history of hypertension

123 (10.4)^b

1342 (14.7)^c

370 (17.6)^d

69 (22.9)^d

Delivery

 Weight(kg)

61.0 (57.0–65.0)^b

70.0 (66.0–75.0)^c

81.6 (77.0–87.0)^d

94.0 (88.0–100.0)^e

 Total GWG (kg)

15.0 (12.0–18.0)^b

14.0 (11.0–17.0)^c

12.0 (9.0–15.0)^d

10.0 (7.0–14.0)^e

 Gestational age (weeks)

39.0 ± 1.02^bc

39.0 ± 1.03^c

38.9 ± 1.04^b

38.9 ± 1.11^b

 Birth weight (g)

3250 (3012–3500)^b

3415 (3150–3690)^c

3500 (3210–3800)^d

3560 (3210–3900)^d

Biochemical indicators at the end of pregnancy

 HbA1c (%)

5.2 (5.0–5.5)^b

5.3 (5.1–5.6)^c

5.4 (5.1–5.7)^d

5.5 (5.3–5.8)^e

 HbA1c (mmol/mol)

33 (31–37)

34 (32–38)

36 (32–39)

37 (34–40)

 Total cholesterol(mmol/L)

5.89 ± 1.15^b

5.74 ± 1.18^c

5.52 ± 1.13^d

5.28 ± 1.14^e

 HDL(mmol/L)

1.75 ± 0.43^b

1.71 ± 0.41^c

1.65 ± 0.37^d

1.61 ± 0.34^d

 LDL(mmol/L)

3.06 ± 0.74^b

2.87 ± 0.75^c

2.74 ± 0.73^d

2.63 ± 0.73^d

 Triglycerides(mmol/L)

2.68 (2.14–3.45)^b

3.02 (2.37–3.91)^c

3.10 (2.45–4.01)^c

3.12 (2.51–3.93)^c

Adverse outcomes

467 (39.6)^b

5160 (56.5)^c

1521 (72.5)^d

241 (80.1)^e

 Gestational hypertension

10 (0.8)^b

149 (1.6)^b

91 (4.3)^c

31 (10.3)^d

 Preeclampsia

10 (0.8)^b

173 (1.9)^b

107 (5.1)^c

36 (12.0)^d

 Cesarean section

369 (31.3)^b

4128 (45.2)^c

1257 (59.9)^d

204 (67.8)^d

 LGA

123 (10.4)^b

1889 (20.7)^c

645 (30.8)^d

110 (36.5)^d

 SGA

39 (3.3)^b

224 (2.5)^b

40 (1.9)^b

4 (1.3)^b