Table 1 Clinical characteristics of the study population

Mothers

Pre-pregnancy BMI (kg/m2)

17.50 ± 0.79

21.06 ± 1.64

26.17 ± 0.84

29.91 ± 1.64

20.89 ± 2.82

< 0.001

Maternal age (years)

28.85 ± 3.76

30.56 ± 4.19

31.49 ± 4.36

30.84 ± 4.09

30.29 ± 4.19

< 0.001

Gestational weeks

39.24 ± 1.31

39.22 ± 1.40

39.04 ± 1.61

39.20 ± 1.34

39.21 ± 1.39

0.075

Education level

< 0.001

<High school

121 (10.97%)

459 (11.44%)

67 (17.36%)

22 (19.47%)

669 (11.92%)

High school

170 (15.41%)

613 (15.28%)

75 (19.43%)

20 (17.7%)

878 (15.64%)

>High school

812 (73.62%)

2940 (73.28%)

244 (63.21%)

71 (62.83%)

4067 (72.44%)

Parity

< 0.001

Nulliparous

775 (70.26%)

2275 (56.7%)

152 (39.38%)

61 (53.98%)

3263 (58.12%)

Secundiparous

299 (27.11%)

1568 (39.08%)

206 (53.37%)

45 (39.82%)

2118 (37.73%)

Multiparous

29 (2.63%)

169 (4.21%)

28 (7.25%)

7 (6.19%)

233 (4.15%)

Infant

Infant sex

0.552

Male

579 (52.49%)

2168 (54.04%)

203 (52.59%)

55 (48.67%)

3005 (53.53%)

Female

524 (47.51%)

1844 (45.96%)

183 (47.41%)

58 (51.33%)

2609 (46.47%)

Birthweight

3089.1 ± 402.7

3208.9 ± 436.7

3273.5 ± 493.8

3331.1 ± 424.1

3192.3 ± 437.6

< 0.001

Length (cm)

49.21 ± 1.75

49.53 ± 1.91

49.46 ± 3.40

49.93 ± 1.87

49.47 ± 2.02

< 0.001

Head (cm)

33.24 ± 1.21

33.55 ± 1.42

33.78 ± 2.35

33.90 ± 1.32

33.51 ± 1.47

< 0.001

MTHFR A1298C

0.524

AA

2376 (71.5%)

214 (6.44%)

70 (2.11%)

663 (19.95%)

3323 (64.35%)

AC

1417 (71.06%)

153 (7.67%)

40 (2.01%)

384 (19.26%)

1994 (38.61%)

CC

219 (73.74%)

19 (6.4%)

3 (1.01%)

56 (18.86%)

297 (5.75%)

MTHFR C677T

0.324

CC

2130 (71.4%)

199 (6.67%)

52 (1.74%)

602 (20.18%)

2983 (57.77%)

CT

1558 (71.57%)

159 (7.3%)

46 (2.11%)

414 (19.02%)

2177 (42.16%)

TT

324 (71.37%)

28 (6.17%)

15 (3.3%)

87 (19.16%)

454 (8.79%)

Hcy

7.17 ± 1.54

7.11 ± 1.54

7.28 ± 1.75

7.08 ± 1.52

7.13 ± 1.56

0.295