Researchers have found that children's DNA expression can be altered by length of pregnancy.
'Our new findings indicate that these DNA changes may influence the development of fetal organs' said Simon Kebede Merid, of the Karolinska Institutet in Sweden and first author of the study, which was published in Genome Medicine.
Epigenetic changes are chemical modifications that sit on top of the DNA, they do not change the DNA sequence but can influence genetic activity. They are known to be important during the gestational period as a way of controlling gene expression, with consequences for development and growth. The chemical modification tracked in this study, called DNA methylation, can influence the level to which a gene is activated, and in turn, how much of a particular protein is made.
The team also looked at samples from children aged four to 18 years. Although most of the DNA methylation patterns detected at birth did not persist into childhood, 17 percent were stable from birth to adolescence. That means that for certain genes, DNA methylation levels influenced by gestational age at birth persist for many years.
Premature birth – being born at less than 37 weeks of pregnancy - affects between five and ten percent of all children. Although most grow and develop normally, premature birth can cause problems including neurodevelopmental disorders and respiratory and lung disease. These problems are more likely in severely premature infants.
'Now we need to investigate whether the DNA changes are linked to the health problems of those born prematurely' said corresponding author Professor Erik Melén, also from the Karolinska Institutet.
This study underlies the current focus on understanding the link between epigenetics, the environment and health in development and pregnancy. The international teams involved form part of the Pregnancy and Childhood Epigenetics (PACE) consortium, and used contributions from 26 studies.
'We hope that our findings will contribute valuable knowledge about fetal development, and in the long-term new opportunities for better care of premature babies', said Professor Melén.