| Health Status > Infants
LOW BIRTH WEIGHT
In 2003, 324,064 infants were born at low birth
weight (less than 2,500 grams, or 5 pounds 8 ounces); this represented
7.9 percent of all live births. 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
three decades.
Low birth weight rates differ by maternal age,
with mothers younger than 15 and older than 45 years of age most
likely to deliver low birth weight infants. Much of the incidence
of low birth weight among older mothers is due to an increase in
the proportion of multiple births. Multiple births are much more
likely to be low birth weight than are singletons: in 2003, 58.2
percent of all multiple births were low birth weight. The increased
frequency of multiple births among older mothers is largely due
to the increasing use of assisted reproductive technologies and
the fact that older mothers are also more likely than younger mothers
to conceive multiples naturally. Although the increase in multiple
births is a contributing factor to the increase in low birth weight
rates, low birth weight also increased among singleton deliveries.
The low birth weight rate among non-Hispanic
Black infants (13.6 percent) has not declined significantly since
1991. The rates among non-Hispanic White and Hispanic infants were
considerably lower in 2003 (7.0 and 6.7 percent, respectively).
The rate of low birth weight among infants born to smokers was substantially
higher than among nonsmokers (12.4 versus 7.7 percent) in 2003.
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.
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Line Chart: Low Birth Weight Among Infants, by
Race/Ethnicity: 1985-2003
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