Infants born with an older mother may have an increased risk for childhood cancer, according to a study the Unversity of Minnesota’s Masonic Cancer Center released Monday.

For every five-year increase in a mother’s age the child’s risk of common cancers increased by seven to ten percent, said study leaders Logan Spector, an assistant professor of pediatrics and cancer epidemiology research and Kimberly Johnson, a post doctoral fellow in pediatric epidemology.

The researchers gathered information from birth registries from across the US, and looked at data for 17,672 children between 0-14 years.

Explanations for the higher risk could include age-related changes to hormone levels during pregnancy, or changes to the DNA passed on to the infant.

The percentage of women older than 30 that have had babies has increased by about 19 percent from 1970 to 2005, according to the press release from the Masonic Cancer Center.

The age of the father did not seem to impact cancer risk, researchers said in the press release.