A new research study showing that stress in pregnant rats can shorten the length of pregnancy in subsequent generations could provide clues to the causes of preterm birth in humans.
A multidisciplinary team of researchers from the University of Lethbridge, along with a University of Alberta medical researcher, studied successive generations of stressed rat mothers. Not only did the stressed animals have shorter pregnancies, they gained less weight during pregnancy and had higher blood glucose levels. Their offspring were smaller and had delays in behavioural development. The effects were amplified over succeeding generations.
“The study is based on a unique rat cohort of maternal stress that includes four generations,” says Dr. Gerlinde Metz, a professor of neuroscience and Alberta Heritage Foundation Medical Senior Scholar at the U of L and one of the researchers on the team. “We show that stress during pregnancy induces an epigenetic footprint that will be passed on to future generations to influence health and disease, such as preterm birth risk, diabetes and behaviour.”
Epigenetic refers to an external influence that changes the expression of a gene, rather than changes of the gene itself. Scientists know that exposure to certain chemicals or diet can cause epigenetic changes, but recent research has shown traumatic experiences can also leave a mark that can be transferred from one generation to the next.
The World Health Organization, in its Born Too Soon report, indicates 15 million babies, about one in 10, are born too soon every year. Figures from the Alberta Children’s Hospital show Alberta has the highest preterm birth rate of all Canadian provinces. Babies born prematurely are at a greater risk of death, developmental delay and health conditions than babies born at term. The cause of preterm birth is unknown in more than half of cases.
The study helps identify biomarkers, or indicators, of disease to better predict the risk of preterm birth and find ways to prevent it.
“This new paradigm may model the origin of the causes of many human preterm births,” says Metz. “Preterm births in humans are likely due to several factors but the data from this study offer a platform for further studies into the predictors and interventions for preterm births.”
The study is published in the current edition of BioMed Central, a peer-reviewed online journal available to the public.
Funding agencies that provided support for this research include Alberta Innovates-Health Solutions, the Natural Sciences and Engineering Research Council of Canada and the Canadian Institutes of Health Research.