Table 2.

Maternal and neonatal outcomes, overall and across-prepregnancy body mass index (n = 3208)

		Prepregnancy BMI
	All	Underweight	Normal weight	Overweight	Obesity	p-valuea
	n = 3208	n = 240	n = 2067	n = 583	n = 318
%
Type of pregnancy (n = 3208)
Multiple	1.3	0.9	1.3	1.5	1.6	0.86
Single	98.7	99.1	98.7	98.5	98.4
Mean of GWG (in kg) (n = 3162)
	13.2	14.5	13.9	12.6	8.7	<10−3
Gestational weight gain (n = 3162)b
Within IOM	35.5	48.8	36.5	29.5	29.0	<10−3
Below IOM	27.5	35.5	31.5	12.1	23.5
Above IOM	37.0	15.7	32.0	58.3	47.5
Gestational diabetes mellitus (n = 3204)
No	92.3	98.6	94.4	88.8	80.7	<10−3
Yes	7.7	1.4	5.6	11.2	19.3
Hypertensive complicationsc (n = 3204)
No	96.5	98.4	97.6	96.8	87.4	<10−3
Yes	3.5	1.6	2.4	3.2	12.6
Delivery mode (n = 3200)
Vaginal	81.4	89.6	82.9	77.5	73.2	<10−3
Cesarean	18.6	10.4	17.1	22.5	26.8
Gestational age at birth (n = 3183)
≥ 37 amenorrhea weeks	96.4	94.3	96.5	96.8	96.3	0.50
33-36 amenorrhea weeks	3.6	5.7	3.5	3.2	3.7
Infant’s sex (n = 3200)
Male	49.4	48.6	49.6	49.6	47.8	0.95
Female	50.6	51.4	50.4	50.4	52.2
Infant’s birth weight (n = 3202)
[2.5 kg-4 kg[	89.0	85.7	89.8	89.1	86.4	<10−3
≥4 kg	7.4	3.8	6.8	8.8	11.1
<2.5 kg	3.6	10.5	3.4	2.2	2.6
Apgar score at 5 min (n = 3181)
10	94.7	96.5	95.2	93.2	93.6	0.40
8-9	4.6	3.1	4.4	5.9	4.8
≤7	0.7	0.3	0.4	1.0	1.6

^aAdjusted Wald test P value for comparisons across pBMI classes

^bGestational weight gain in agreement with recommendations defined in 2009 by the IOM

^cHypertensive complications including hypertension and/or preeclampsia during pregnancy