Table 3.

Maternal predictors of low (<2500 gms) versus normal birth weight.

Comparison	Odds ratio (95% CI)	P
Smoked before pregnancy only/never smoked	1.113 (0.961–1.289)	0.1529
Smoked before and during pregnancy/never smoked	1.624 (1.424–1.853)	<0.0001
Age	1.033 (1.023–1.044)	<0.0001
First live birth/previous live birth	1.832 (1.658–2.024)	<0.0001
Not married/married	1.198 (1.058–1.356)	0.0043
Education ≤ 12 yrs/> 12 yrs	1.176 (1.055–1.311)	0.0034
Prepregnancy BMI	1.004 (0.997–1.011)	0.2993
Annual HH income ≤ $20 k/> $20 k	0.895 (0.787–1.017)	0.0882
Urban or suburban/rural town or isolated rural	0.970 (0.885–1.063)	0.5119
Nonwhite/white	1.089 (0.824–1.439)	0.5490
Drank alcohol prior to pregnancy/did not drink alcohol	0.838 (0.758–0.926)	0.0005
Drank alcohol in last 3 months of pregnancy/did not drink	0.799 (0.657–0.972)	0.0248
Gestational age when being sure she is pregnant	1.020 (1.004–1.036)	0.0118
Gestational age at first prenatal visit	0.972 (0.957–0.987)	0.0003
Pregnancy weight gain < recommended/recommended	2.161 (1.935–2.413)	<0.0001
Pregnancy weight gain > recommended/recommended	0.721 (0.646–0.804)	<0.0001

Logistic regression results with infant birth weight < 2500 gms as the dependent variable: compared to normal weight infants, infants are more likely to be born weighing < 2500 gms if their mother was older, was having her first child, was not married, had no education past high school, was not sure she was pregnant until later in gestation, had a weight gain < recommended range (compared to within recommended range), or smoked before and during pregnancy. Infants were less likely to be underweight if mother had a gestational weight gain > the recommended amount of weight (compared to within recommended range), had her first prenatal visit later in gestation, or drank alcohol before or during pregnancy.