July 16, 2008 -- The effects of premature birth may last well beyond
childhood and affect adult mental and physical health in many ways, according
to a new study.
Researchers in Norway analyzed the health and birth records of nearly a
million adults and found the risk of mental and health disorders ranging from
cerebral palsy to mental
retardation in adulthood increased significantly with decreasing gestational
age at birth.
"Recent advances in the care of premature infants have resulted in
increasing rates of survival," researcher Dag Moster, MD, PhD, of the
University of Bergen in Norway, and colleagues write in the New England
Journal of Medicine.
"However, the increased prevalence of medical disabilities, learning
difficulties, and behavioral and psychological problems among surviving preterm
infants has raised concerns that these infants may have difficulties coping
with adult life."
Premature birth is defined as birth prior to 37 weeks gestation.
Prematurity's Lasting Effects
In the study, researchers analyzed national registry information on 903,402
infants without birth defects who were born
between 1967 and 1983 and noted any medical or social disabilities documented
Compared with adults who had been born at 37 weeks gestation or later, those
who had a premature birth had a much higher risk of a range of medical and
social problems. For example:
The rate of cerebral palsy was 0.1% for those born at term vs. 9.1% among
the earliest preemies born at 23 to 27 weeks.
The prevalence of mental retardation was 0.4% among full-term infants
compared with 4.4% among the most premature infants.
Less than 2% of full-term infants were receiving a disability pension as
adults vs. nearly 11% of the most premature infants.
Researchers found that among adults who did not have medical disabilities,
gestational age at birth was also associated with education level achieved,
income, receipt of Social Security benefits, and starting a family. But
prematurity was not associated with unemployment or the establishment of
"Despite the higher prevalence of disabilities among persons who were
born prematurely, it should be recognized that a large proportion of the adults
who were born prematurely and who did not have severe medical disabilities
completed higher education and seemed to be functioning well," the
But the results suggest that there is a continuous relationship between
prematurity and a wide range of medial and social issues and more study is
needed to identify risk factors that predict long-term problems associated with
premature birth and develop preventive strategies.