Researchers have long struggled to explain why some people living in certain regions of the U.S. and UK are more likely to develop stroke than others.

Now, two experts are looking to the womb to explain this uneven pattern. They found that UK regions marked by high stroke rates also showed high rates of death among mothers and infants in the early 20th century, the years when many stroke patients were born.

This trend suggests that the mysterious variations in stroke rates may be the result of historical, regional differences in maternal health, they write in a report released Thursday.

If this theory proves correct, study author Dr. David J. P. Barker of the University of Southampton in the UK told Reuters Health that, in the next generation, stroke prevention may lie “in good nutrition among mothers at conception and beyond.”

More here.