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 through 2003.
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 criminal activity.
"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 researchers write.
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.