Table 1 Demographics of study participants (n = 387)

Maternal age, y

28.5 ± 3.7

21.0, 41.0

28.1, 28.3

Prepregnancy BMI, kg/m²

20.5 ± 2.5

15.8, 30.8

20.2, 20.7

Paternal BMI, kg/m²

24.1 ± 2.9

16.7, 33.9

23.8, 24.4

Physical activity < 30 min/d

165(42.6)

–

0.38, 0.48

Paternal achohol use

214(55.3)

–

0.50, 0.60

Paternal smoking status

176(45.5)

–

0.40, 0.51

Maternal Education ≤12 y

114(29.5)

–

0.66, 0.75

Paternal education ≤12 y

106(27.4)

–

0.68, 0.77

Family income < 5000 yuan/mo

95(24.5)

–

0.71, 0.80

Gestational week (week)

37.4 ± 2.9

28.0, 41.0

37.1, 37.7

Female

188(48.6)

–

0.44, 0.54

Cesarean section

219(56.6)

–

0.38, 0.49

Breastfeeding duration< 6 mo

323(83.5)

–

0.13, 0.21

Birth weight (kg)

2.64 ± 0.69

1.10, 4.00

2.59, 2.73

BMI z score at birth

−0.14 ± 1.38

−4.05, 3.10

−1.43, −1.16