LOW BIRTH WEIGHT
In 2002, 314,077 babies (7.8 percent of all live births) were
of low birth weight, weighing less than 2,500 grams, or 5 pounds
8 ounces, at birth. This rate represented a slight increase from
the previous year. The percentage of newborns born at low birth
weight has risen steadily from a low of 6.7 percent in 1984 and
is currently at the highest level recorded in the past 3 decades.
The highest rates of delivering a low birth weight infant are
among mothers younger than 15 years and older than 45. Much of the
incidence of low birth weight among older mothers (older than 44)
is due to an increase in the proportion of multiple births, as the
use of assisted reproductive technologies increases. Multiple births
accounted for 24 percent of low birth weight infants in 2002 compared
to only 15 percent in 1980. However, the low birth weight rate among
singleton infants increased as well.
Although the non-Hispanic Black low birth weight has declined slightly
from a high of 13.6 percent in 1991, it remains considerably higher
than the rate for non-Hispanic White (6.9 percent) and Hispanic
(6.5 percent) infants. In 2002, the percent of low birth weight
infants born to smokers (12.2 percent) was substantially higher
than among nonsmokers (7.5 percent). This significant differential
has been consistently observed among both non-Hispanic Black and
non-Hispanic White infants. Other factors associated with increased
risk of low birth weight include maternal poverty and low levels
of educational attainment.
Low birth weight is one of the leading causes of neonatal mortality.
Low birth weight infants are more likely to experience long-term
disability or to die during the first year of life than are infants
of normal weight.