Table 1 Characteristics of the participants

Mother

 Age at delivery (years)

   < 25

247

(4.2)

52

(7.9)

41

(9.5)

68

(12.4)

< 0.001

   25–29

1393

(23.8)

216

(32.9)

145

(33.7)

191

(34.7)

   30–34

2347

(40.1)

244

(37.1)

158

(36.7)

176

(32.0)

   ≥ 35

1867

(31.9)

145

()22.1

86

(20.0)

115

(20.9)

 Pre-pregnancy body mass index (kg/m²)

   < 18.5

785

(13.4)

88

(13.4)

66

(15.4)

89

(16.2)

< 0.001

   18.5–24.9

4475

(76.4)

496

(75.5)

306

(71.2)

373

(67.8)

   ≥ 25.0

594

(10.2)

73

(11.1)

58

(13.4)

88

(16.0)

 Educational level

   Junior high school or high school

1635

(27.9)

205

(31.2)

162

(37.7)

219

(39.8)

< 0.001

   Technical college or junior college

2310

(39.5)

251

(38.2)

172

(40.0)

200

(36.4)

   University or graduate school

1909

(32.6)

201

(30.6)

96

(22.3)

131

(23.8)

 Smoking status in early pregnancy

   Never

4024

(68.7)

402

(61.2)

234

(54.4)

265

(48.2)

< 0.001

   Quit before pregnancy

1355

(23.2)

164

(25.0)

103

(24.0)

126

(22.9)

   Quit after pregnancy

432

(7.4)

77

(11.8)

77

(17.9)

125

(22.7)

   Smoked during early pregnancy

43

(0.7)

14

(2.1)

16

(3.7)

34

(6.2)

 Alcohol consumption in early pregnancy

   Never

2752

(47.0)

295

(44.9)

182

(42.3)

223

(40.6)

0.009

   Former

1899

(32.4)

231

(35.2)

155

(36.1)

220

(40.0)

   Current

1203

(20.6)

131

(19.9)

93

(21.6)

107

(19.5)

 Parity

   ≥ 1

3485

(59.5)

214

(32.5)

142

(33.0)

157

(28.6)

< 0.001

   0

2369

(40.5)

443

(67.5)

288

(67.0)

393

(71.4)

 Employment status in early pregnancy

   Employed

3478

(59.4)

417

(63.5)

264

(61.4)

341

(62.0)

0.07

   Not employed

2220

(37.9)

215

(32.7)

151

(35.1)

191

(34.7)

   Other

156

(2.7)

25

(3.8)

15

(3.5)

18

(3.3)

   With folic acid supplementation

3484

(59.5)

421

(64.1)

271

(63.0)

348

(63.3)

0.03

 Morning sickness

   Never

811

(13.9)

104

(15.8)

67

(15.6)

89

(16.2)

0.001

   Nausea only

2769

(47.3)

270

(41.1)

197

(45.8)

211

(38.4)

   Vomiting, able to eat

1698

(29.0)

219

(33.3)

119

(27.7)

180

(32.7)

   Vomiting, unable to eat

576

(9.8)

64

(9.7)

47

(10.9)

70

(12.7)

   Insomnia

2072

(35.4)

266

(40.5)

185

(43.0)

246

(44.8)

< 0.001

   With psychological distress

1842

(31.5)

232

(35.3)

180

(41.9)

248

(45.1)

< 0.001

   With postnatal bonding disorder

823

(14.1)

115

(17.5)

86

(20.0)

108

(19.6)

< 0.001

   Energy intake (kcal/day)

1662

± 505.1

1574

± 489.9

1553

± 524.7

1457.8

± 543.3

< 0.001

   Cereal intake (g/day)

426.5

± 108.9

415.8

± 109.5

390.8

± 103.2

377.2

± 110.0

< 0.001

   Meat intake (g/day)

68.7

± 38.1

76.9

± 37.9

79.2

± 37.5

80.0

± 38.2

< 0.001

   Fish intake (g/day)

37.6

± 28.8

35.5

± 24.1

38.2

± 29.0

37.2

± 31.5

0.32

   Bean intake (g/day)

62.6

± 61.1

58.5

± 56.0

53.4

± 50.4

59.7

± 58.1

0.007

   Seaweed intake (g/day)

6.5

± 5.8

5.6

± 4.5

5.8

± 4.9

5.3

± 4.9

< 0.001

   Vegetable intake (g/day)

161.6

± 111.5

139.5

± 79.0

145.6

± 76.0

140.0

± 95.6

< 0.001

   Fruit intake (g/day)

148.2

± 128.0

141.7

± 117.1

156.6

± 136.3

155.4

± 143.2

0.16

Child

 Birth- weight (g)

3064

± 369.8

3069

± 369.3

3036

± 378.5

3027

± 341.4

0.06

 Boy

2963

(50.6)

342

(52.1)

212

(49.3)

298

(54.2)

0.34

 Breastfeeding at 1 year

3602

(61.5)

393

(59.8)

253

(58.8)

310

(56.4)

0.08

 Developmental delays at 2 years of age

835

(14.3)

94

(14.3)

71

(16.5)

105

(19.1)

0.01

 Developmental delays at 3.5 years of age

768

(13.1)

98

(14.9)

60

(14.0)

81

(14.7)

0.45