Healthcare professionals have long cautioned women that getting pregnant later in life increases the risk of complications. However, a new study released this week suggests that advanced maternal age isn’t the defining factor in the connection between pregnancy and one particular risk: stroke.

A study from Columbia University Medical Center and New York-Presbyterian found that for younger women, the risk of stroke increases when they become pregnant. Researchers analyzed data on all women hospitalized for stroke between 2003 and 2012 in New York state.

While the data showed that the overall risk of stroke during or soon after pregnancy increased with age, comparisons within age groups found a new risk. For women between ages 12 and 24, pregnancy doubled the risk of stroke.

The likelihood of a stroke increased 60 percent with pregnancy for women aged 25 to 34 years and in the under-35 age group, one in five strokes were related to pregnancy.

Senior author of the study, Joshua Z. Willey, MD, said comparisons within age groups make this study unique. There is little research comparing pregnant and non-pregnant women of the same age.

It’s also a key to healthy pregnancies. As pregnancy-associated stroke rises, the study’s lead author, Eliza C. Miller, MD, says more research is coming.

“We need more research to better understand the causes of pregnancy-associated stroke, so that we can identify young women at the highest risk and prevent these devastating events,” said Miller.

You can read the full study at JAMA Neurology.