Table 1 Folate variables and maternal characteristics

Total

66014

(100)

313

(167–558)

16023

(24)

12877

(20)

37114

(56)

<25

7561

(12)

258

(154–528)

849

(11)

942

(13)

5770

(76)

Maternal age in years

25-29

22672

(34)

324

(170–562)

<0.0001

5121

(23)

4821

(21)

12730

(56)

<0.0001

30-34

27993

(42)

319

(168–562)

7726

(28)

5894

(21)

14373

(51)

>34

7788

(12)

315

(170–562)

2327

(30)

1220

(16)

4241

(55)

Pre-pregnancy BMI in kg/m²

<18.5

19\31

(3)

343

(179–575)

432

(22)

351

(18)

1148

(60)

18.5-24.9

42611

(65)

328

(173–566)

<0.0001

10773

(25)

8637

(20)

23201

(54)

<0.0001

25-30

13839

(21)

289

(160–548)

3228

(23)

2651

(19)

7960

(58)

≥30

5970

(9)

268

(151–533)

1305

(22)

953

(16)

3712

(62)

Missing

1663

(3)

250

(156–517)

285

(17)

285

(17)

1093

(66)

0

34825

(53)

355

(180–580)

9324

(27)

6480

(19)

19021

(55)

1

20028

(30)

281

(159–545)

<0.0001

4528

(23)

4531

(23)

10969

(55)

<0.0001

Parity

2

9005

(14)

245

(156–517)

1787

(20)

1570

(17)

5648

(63)

3+

2101

(3)

224

(149–451)

370

(18)

285

(14)

1446

(69)

Missing

55

(0.1)

353

(166–566)

14

(26)

11

(20)

30

(55)

Marita status

Yes

63518

(96)

315

(168–559)

<0.0001

15714

(25)

12661

(20)

35143

(55)

<0.0001

No

2496

(4)

266

(158–531)

309

(12)

216

(9)

1971

(79)

Maternal education in years

<13

20198

(31)

244

(150–515)

3263

(16)

2886

(14)

14049

(70)

13 - 16

27606

(42)

338

(172–567)

<0.0001

7118

(26)

5849

(21)

14639

(53)

<0.0001

>16

16838

(26)

374

(187–581)

5340

(32)

3916

(23)

7582

(45)

Missing

1372

(2)

283

(161–550)

302

(22)

226

(17)

844

(62)

History of preterm delivery

No

63698

(97)

314

(168–559)

<0.0001

15510

(24)

12411

(20)

35777

(56)

0.047

Yes

2205

(3)

276

(158–539)

487

(22)

435

(20)

1283

(58)

Missing

111

(0.2)

297

(175–560)

26

(23)

31

(28)

54

(49)

History of abortion

No

45164

(68)

315

(168–559)

0.15

10262

(23)

8930

(20)

25972

(58)

<0.0001

Yes

12418

(19)

308

(166–558)

3932

(32)

2296

(19)

6190

(50)

Missing

8432

(13)

308

(165–557)

1829

(22)

1651

(20)

4952

(59)

Never

60452

(92)

322

(170–563)

15339

(25)

12271

(20)

32842

(54)

Smoking habits

Occasionally

1741

(3)

261

(158–511)

<0.0001

243

(14)

226

(13)

1272

(73)

<0.0001

Daily

3449

(5)

217

(141–485)

378

(11)

316

(9)

2755

(80)

Missing

372

(0.6)

236

(148–500)

63

(17)

64

(17)

245

(66)

Alcohol consumption in units/week

No alcohol

58659

(89)

314

(167–559)

14448

(25)

11528

(20)

32683

(56)

<0.5

6155

(9)

311

(170–556)

0.21

1326

(22)

1164

(19)

3665

(60)

<0.0001

≥0.5

1200

(2)

286

(167–531)

249

(21)

185

(15)

766

(64)

Partners with income of >300,000

0

18364

(28)

279

(161–540)

<0.0001

3176

(17)

2904

(16)

12284

(67)

1

27212

(41)

309

(166–557)

6460

(24)

5451

(20)

15301

(56)

<0.0001

2

18608

(28)

360

(178–579)

6130

(33)

4247

(23)

8231

(44)

NOK/year

Missing

1830

(3)

264

(158–533)

257

(14)

275

(15)

1298

(71)

Baby's sex

Male

33791

(51)

309

(166–558)

0.07

8190

(24)

6525

(19)

19076

(57)

0.4

Female

32223

(49)

316

(169–559)

7833

(24)

6352

(20)

18038

(56)

Tertiles of energy intake in MJ

1

22005

(33)

272

(127–525)

5577

(25)

4338

(20)

12090

(55)

2

22005

(33)

317

(166–561)

<0.0001

5511

(25)

4485

(20)

12009

(55)

<0.0001

3

22004

(33)

344

(211–600)

4935

(22)

4054

(18)

13015

(59)