Although researchers have long known that low birth weight (defined as a newborn weighing 5.5 lbs or less) can be influenced by many factors including the biological interaction of the mother and the fetus, the parent's socioeconomic status, and medical care, these factors are little understood and public health initiatives aimed at reducing the incidence of low birth weight have been largely unsuccessful.
National rates of low birth weight have actually risen over the past decade, a trend that has both negative economic and health consequences.
The study confirms established notions that race plays a role in low birth weight, with an incidence of over 11-percent of births to black mothers compared to less than 5-percent of births to white mothers. Smoking or drinking during pregnancy doubles the likelihood of low birth weight in newborns, as does a mothers weight gain of less than 20 lbs. during pregnancy.
Dr. Lindsay Thompson, who led the research at Dartmouth Medical School says, "I was surprised that the regional variation across the country was still so high after accounting for other known factors. It is clear that place of residence is an important factor in neonatal outcomes. This is encouraging because these regions are linked to social and healthcare systems, and these are amenable to improvement."
