FIGURE 1
SOURCE: Greg R. Alexander, Mary Ann Pass, and Martha Slay.
in children have been attributed to preterm birth.
Preterm infants have an increased risk of develop-
mental delay, cerebral palsy, mental retardation, sen-
sory impairment, learning and school-related
problems, and other disabilities. Moreover, the
health-care costs associated with an extremely small
baby or early birth are more than ten times greater
than those of normal weight infants. The persistent
disparity in infant mortality rates among ethnic
groups in the United States has also been related to
ethnic differences in preterm birthrates. Further,
high preterm birthrates in the United States have
been identified as a major contributor to this nation’s
relatively poor ranking for infant mortality among
developed countries.
Considerable effort was expended in the United
States during the last few decades of the twentieth
century to reduce the rates of preterm delivery and
low birthweight. In 1985 the Institute of Medicine
promoted increasing access to prenatal care and im-
proving the content of care as a means to improve the
rates of these adverse perinatal outcomes. Since then,
considerable effort has been expended to improve
prenatal care and reduce preterm births. Between
1981 and 1995, the percent of women starting prena-
tal care in the first trimester increased 6.1 percent,
from 76.9 percent to 81.6 percent. Over the same pe-
riod, the percent of women with adequate utilization
of prenatal care increased 37.9 percent, from 29.3
percent to 40.4 percent, while the percent of women
who inadequately used prenatal care decreased 33.3
percent, from 13.5 percent to 9 percent. Notwith-
standing improvements in access to and use of prena-
tal care, preterm and low birthweight rates in the
United States continued to increase (see Figure 1). By
1995, a Future of Children report on low birthweight
concluded that prenatal care in its present form ‘‘does
little to prevent low birth weight or preterm birth’’
(Shiono and Behrman 1995). Other reviews in the
late 1990s also concluded that there is little done dur-
ing the standard prenatal care visit to reduce the risk
of very low birthweight or to prevent preterm deliv-
ery.
Several explanations can be proposed for the on-
going increase in preterm birthrates in the United
States. The possible factors driving these trends in-
clude:- changes in vital record reporting (i.e., very pre-
term infants once reported as fetal deaths are
now being registered as live births); - a rising incidence of multiple births, the infants
from which are more likely to be preterm; - an increase in the percentages of unmarried
and older aged mothers, who are at greater risk
of having a preterm delivery; and - changes in obstetric practice that have lead to
earlier delivery of pregnancies deemed at risk of
a poor outcome.
Improvements in the early and adequate use of
prenatal care services, coupled with developments in
PREMATURE INFANTS 323