Low birthweight

Low Birthweight is the percentage of live births where the infant weighed less than 2,500 grams (approximately 5 lbs., 8 oz.).

Measure Tabs

Reason for Ranking

Low birthweight (LBW) is unique as a health outcome because it represents multiple factors: infant current and future morbidity, as well as premature mortality risk, and maternal exposure to health risks. The health associations and impacts of LBW are numerous.

In terms of the infant’s health outcomes, LBW serves as a predictor of premature mortality and/or morbidity over the life course.[1] LBW children have greater developmental and growth problems, are at higher risk of cardiovascular disease later in life, have a greater rate of respiratory conditions, and have higher rates of cognitive problems such as cerebral palsy, and visual, auditory, and intellectual impairments.[2-5]

From the perspective of maternal health outcomes, LBW indicates maternal exposure to health risks in all categories of health factors, including her health behaviors, access to health care, the social and economic environment the mother inhabits, and environmental risks to which she is exposed. Authors have found that modifiable maternal health behaviors, including nutrition and weight gain, smoking, and alcohol and substance use or abuse can result in LBW.[6]

Measurement Strengths and Limitations

Health risks are greatest for very low birthweight (below 1,500 grams) babies but infants born below 2,500 grams also face increased risk of morbidity and premature mortality. Low birthweight is preferred to very low birthweight in the County Health Rankings because it is a more common event, allowing for better data coverage. Although gestational age may be a better measure than low birthweight as it better accounts for a child’s neurological and physical development at birth, gestational age can be difficult to accurately ascertain, whereas birthweight is easily measured and reported.