High blood pressure during pregnancy could dramatically increase a woman’s stroke risk, according to a new research.

Dr Aravind Ganesh, a neurology resident at the University of Calgary, said that they’ve found that women who had high blood pressure during pregnancy could be at higher risk of stroke, particularly if they had pre-eclampsia, which is a more severe form of high blood pressure.

He said that the elevated risk of stroke could be as high as 40 %.

Dr Ganesh, along with Neha Sarna (medical student), Dr Rahul Mehta (internal medicine resident) and senior author Dr Eric Smith (stroke neurologist), conducted nine studies specifically looked at hypertension (high BP) during pregnancy and its relationship to future risk of stroke.

The studies followed women for anywhere from one to 32 years after a pregnancy, and found consistent evidence that those with a history of hypertension in pregnancy are more likely to experience stroke in later life.

The exact cause of hypertension during pregnancy is undetermined, but one theory is that some women are genetically predisposed to high blood pressure and the pregnancy brings it on. Even though it might return to normal post-partum, these women need to monitor their blood pressure and to reduce their risk of having a stroke later on.