A low birth weight baby is one that is small for gestational age, which means that the infant is smaller in size than normal for the baby's gender and gestational age. Infants may be low birth weight because of inadequate interuterine growth or premature birth.

Risk factors for low birth weight include:

• poor prenatal care

• alcohol/tobacco use during pregnancy

• teen pregnancy

Mothers who give birth to low birth weight infants generally receive inadequate prenatal care. Low birth weight is not a measure of hospital quality, but rather one way to measure outpatient and prenatal care. Proper preventive care may reduce the likelihood of an infant having a low birth weight.