Table 1A.

Maternal characteristics of the study population according to the Japanese classification

	Underweight	Normal weight	Obese
Prepregnancy BMI (kg/m2)	<18.5; n = 1,159 (19.1%)	18.5 to 24.9; n = 4,239 (69.9%)	≥25; n = 668 (11%)
Maternal age (y)	30.8 ± 4.9**	31.9 ± 4.99	32.7 ± 4.6**
Primiparous rate (%)	57.1**	50.1	40.5**
Maternal height (cm)	158.2 ± 5.4	157.9 ± 5.5	157.3 ± 5.7
Total gestational weight gain (kg)	10.5 ± 4.0	10.7 ± 11.1	7.4 ± 6.1**
Gestational week at delivery	38.3 ± 2.1	38.4 ± 2.0	38.0 ± 2.6*

*p <0.05 vs Normal weight; **p <0.01 vs Normal weight.