Preterm birth linked to diminished long-term survival, reproduction

Washington, Mar 26 : A new study by researchers at the Duke University Medical Center, Durham, N.C., has found that premature babies have an increased risk of death throughout childhood and lower rates of reproduction in adulthood, as compared to full-term babies.

Not much is known about the long-term risk of death and overall health among persons born preterm.

Therefore, Geeta K. Swamy, M.D., of Duke University Medical Center, Durham, N.C., and colleagues conducted a study to determine how preterm birth affects long-term survival, subsequent reproduction and next-generation preterm birth.

"Such information may be useful to practitioners caring for families with survivors of preterm birth as well as parents of preterm infants," the authors said.

For the study, the researchers analyzed data from the Medical Birth Registry of Norway for 1,167,506 births from 1967-1988.

The researchers followed up the group through 2002 for survival. There was also an analysis for those born from 1967-1976 for assessment of educational achievement and reproductive outcomes through 2004.

Out of the 1,167,506 births, 60,354 were found to be preterm. The percentage born preterm was higher among boys than among girls, which is consistent with the male-dominated sex ratio of all births.

Following the analysis, the researchers found that the preterm participants had an increased risk of death throughout childhood.

The mortality rates for boys born at 22 to 27 weeks were 1.33 percent and 1.01 percent for early and late childhood death, with a 5.3 times higher risk for early death, and 7 times higher risk for late childhood death.

For girls born at 22 to 27 weeks, the mortality rate was 1.71 percent for early childhood death, with a 9.7 times higher risk for early childhood death; there were no late childhood deaths.

For 28 to 32 weeks, the early and late childhood mortality rates among boys were 0.73 percent and 0.37 percent, with higher risks of death of 2.5 times, and 2.3 times, respectively.

Girls born at 28 to 32 weeks did not have a significantly increased risk of childhood death.

The researchers also found that reproduction during adulthood was diminished for participants born preterm as compared to those born at term.

In case of both men and women born at 22 to 27 weeks, absolute reproduction was 13.9 percent and 25 percent, with men being 76 percent less likely to reproduce; women, 67 percent less likely.

For kids born at 28 to 32 weeks, absolute reproduction was 38.6 percent and 59.2 percent for men and women, with lower rates of reproduction of 30 percent, and 19 percent, respectively.

Preterm women but not men were at increased risk of having preterm offspring.

"In this study population, preterm birth was negatively associated with both long-term survival and reproduction," the authors said.

The study is published in the March 26 issue of JAMA.

ANI