Table 2A.

Comparison of pregnancy outcomes of obese pregnant women according to the Japanese classification

	Underweight	Normal weight	Obesity
Prepregnancy BMI (kg/m)	<18.5	18.5 to 24.9	≥25
	n = 1,159 (19.1%)	n = 4,239 (69.9%)	n = 668 (11%)
HDP
% (n)	2.5% (n = 29)	4.0% (n = 169)	12.1% (n = 81)
Adjusted OR (95% CI)	0.57** (0.37-0.86)	1	3.32** (2.48-4.45)
GDM
% (n)	1.9% (n = 22)	2.6% (n = 111)	11.2% (n = 75)
Adjusted OR (95% CI)	0.76 (0.48-1.22)	1	3.39** (2.42-4.74)
LGA
% (n)	4.4% (n = 51)	9.5% (n = 402)	20.8% (n = 139)
Adjusted OR (95% CI)	0.43** (0.32-0.58)	1	2.91** (2.31-3.66)
SGA
% (n)	13.5% (n = 156)	9.0% (n = 381)	4.6% (n = 31)
Adjusted OR (95% CI)	1.71** (1.39-2.10)	1	0.81 (0.59-1.09)
Macrosomia
% (n)	0.2% (n = 2)	0.7% (n = 30)	2.5% (n = 17)
Adjusted OR (95% CI)	0.23* (0.05-0.96)	1	4.01** (2.18-7.37)
Spontaneous preterm birth
% (n)	5.8% (n = 64)	2.5% (n = 100)	3.4% (n = 23)
Adjusted OR (95% CI)	2.33** (1.68-3.23)	1	0.81 (0.48-1.40)
Post-term birth
% (n)	5.6% (n = 65)	8.0% (n = 339)	7.2% (n = 48)
Adjusted OR (95% CI)	0.62** (0.47-0.82)	1	1.01 (0.73-1.38)
PPH (CS)
% (n)	1.7% (n = 4)	2% (n = 21)	0.7% (n = 5)
Adjusted OR (95% CI)	0.85 (0.29-2.50)	1	1.04 (0.37-2.91)
PPH (VD)
% (n)	12.1% (n = 112)	15.8% (n = 503)	12.7% (n = 85)
Adjusted OR (95% CI)	0.80 (0.64-1.00)	1	1.45 (1.11-1.91)
Neonatal acidosis
% (n)	7.1% (n = 81)	5.5% (n = 227)	5.1% (n = 34)
Adjusted OR (95% CI)	1.31* (1.01-1.72)	1	0.85 (0.57-1.27)
Neonatal asphyxia
% (n)	2.8% (n = 32)	2.2% (n = 93)	3.0% (n = 20)
Adjusted OR (95% CI)	1.32 (0.88-2.00)	1	1.06 (0.47-2.39)
Total CS
% (n)	20% (n = 229)	24.6% (n = 1,042)	34.6% (n = 231)
Adjusted OR (95% CI)	0.76** (0.64-0.91)	1	1.47** (1.19-1.80)

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