A study published in the journal Nature has found that mothers cut their babies' risk of heart risks in half by exercising before their pregnancy.
One in 100 babies is born with congenital heart defects. Most are minor, but some, including holes between the chambers of the heart, require surgery.
It has been previously established by other studies that older mothers have a higher risk of giving birth to offspring with this defect compared to younger mothers. The scientists, led by Dr. Patrick Y. Jay from the Washington University School of Medicine, wanted to find out why this was.
The experiment involved breeding mice with a genetically high risk of giving birth to pups with a higher risk of heart defects. Half were young mice and the other half were older.
Since egg cells age and deteriorate over time, researchers tested if egg quality was the determining factor. This was then disproved when they placed eggs from young mothers into old mothers and found that the risks were still higher with the later.
They then turned to metabolism, which slows down and becomes less efficient with age. Young and old mice were made to exercise with running wheels several weeks before becoming pregnant.
Results from the experiment showed that young mice, whether they exercised or not, had a 10% chance of producing pups with heart defects. Older mice that exercised significantly lowered the chances to 10% as well compared to the 20% of older mice that did not exercise.
“Most remarkably, voluntary exercise, whether begun by mothers at a young age or later in life, can mitigate the risk when they are older,” said the study. “Thus, even when the offspring carry a causal mutation, an intervention aimed at the mother can meaningfully reduce their risk of congenital heart disease.”
The scientists have yet to figure out how exercise was able to alter the risk equation but speculate that metabolic changes within the uterus are involved.
These findings are purely speculative and do not affirm that the same changes would occur for humans.
Nevertheless, exercise is important for women planning to have children and those already pregnant. "There are so many potential health benefits" for mother and child, said Dr. Jay.
Sources: April 8, 2015. "Mothers’ Exercise May Lower Heart Risks in Newborns". nytimes.com April 9, 2015. "Exercise during pregnancy may reduce baby's risk of heart defects: Study". torontosun.com