Factors predicting birth weight in a low-risk sample: The role of modifiable pregnancy health behaviors

Objectives: The purpose of the present study was to examine background and modifiable pregnancy health behavior factors predicting infant birthweight in an economically and educationally disadvantaged sample with low medical risk. Methods: Participants were recruited from a family practice center in rural Appalachia. Participants: Over 220, predominantly Caucasian and lower SES women with low risk pregnancies were included in the sample. Data were collected through systematic chart review. Half of the women smoked during pregnancy and over 10% gave birth to low birth weight (LBW; < 2500 g) babies. Results: Compared with those who gave birth to normal weight newborns, women with LBW babies had more miscarriages, but did not differ significantly on other background factors. Women who delivered LBW babies gained less weight during pregnancy and were more likely to smoke than remaining women. After control for background factors, modifiable pregnancy health behavior factors (weight gain, prenatal care, smoking, alcohol and substance use) accounted for over 11% of birth weight variance, with nearly 7% attributable solely to smoking. Conclusions: Pregnancy smoking was the strongest behavioral predictor of LBW in this economically and educationally disadvantaged rural sample, suggesting that efforts to reduce LBW in similar populations should include targeting pregnancy smoking.