Table 5.

Maternal predictors of infant born prematurely (<37 wks of gestation).

Comparison	Odds ratio (95% CI)	P
Smoked before pregnancy only/never smoked	0.925 (0.736–1.161)	0.5008
Smoked before and during pregnancy/never smoked	1.010 (0.823–1.239)	0.9261
Age	1.017 (1.002–1.032)	0.0227
First live birth/previous live birth	1.425 (1.230–1.650)	<0.0001
Not married/married	1.046 (0.873–1.254)	0.6238
Education ≤ 12 yrs/> 12 yrs	0.911 (0.769–1.079)	0.2802
Prepregnancy BMI	1.019 (1.009–1.028)	0.0001
Annual HH income ≤ $20 k/> $20 k	1.255 (1.032–1.524)	0.0227
Urban or suburban/rural town or isolated rural	0.884 (0.772–1.012)	0.0740
Nonwhite/white	1.341 (0.825–2.178)	0.2360
Drank alcohol prior to pregnancy/did not drink alcohol	0.787 (0.680–0.911)	0.0013
Did not drink alcohol in last 3 months of pregnancy/drank	0.832 (0.621–1.116)	0.2192
Gestational age when being sure she is pregnant	1.025 (1.006–1.045)	0.0101
Gestational age at first prenatal visit	0.972 (0.949–0.996)	0.0217
Pregnancy weight gain < recommended/recommended	1.645 (1.401–1.931)	<0.0001
Pregnancy weight gain > recommended/recommended	0.721 (0.610–0.853)	0.0001

Logistic regression results with infant being born at < 37 weeks of gestation as the dependent variable. Infants were more likely to be born at < 37 weeks of gestational age which is greater for mothers who were older, were having their first birth, had a higher prepregnancy BMI, lived in a household with an annual income < $20,000/year, were sure they were pregnant at a later gestational age, or had a gestational weight gain < recommended range. Infants were less likely to be born at < 37 weeks of gestational age if their mother drank alcohol before pregnancy, has her first prenatal visit at an earlier gestational age, or had a gestational weight gain <> recommended range.