Women who are pregnant face a 2.4 times more risk of having a stroke than non-pregnant women, according to researchers.
High blood pressure during pregnancy is a leading cause of maternal and foetal mortality worldwide.
Pregnancy-induced high-blood-pressure syndromes include pre-eclampsia, eclampsia and a rare but serious illness called HELLP (hemolysis, elevated liver enzymes and low platelet count).
Pre-eclampsia is a multisystem disorder characterized by high blood pressure and proteinuria (excess protein in urine).
Left untreated, pre-eclampsia can cause serious complications, possibly fatal, in the mother and baby.
In severe pre-eclampsia, patients may develop oliguria (reduced urine output), pulmonary edema (fluid in the lungs), liver dysfunction, thrombocytopenia (low platelet count) and changes in mental status and other cerebral symptoms.
Patients may have headaches, stupor, visual blurring, blindness (often temporary) or seizures.
Pre-eclampsia can progress to eclampsia or HELLP. Pre-eclampsia develops into eclampsia when a patient experiences convulsive seizures or goes into a coma.
HELLP can cause bleeding, liver problems and high-blood-pressure problems, harming both mother and baby.
"Pre-eclampsia/eclampsia-related events are a major cause of maternal disability and maternal and foetal death in the USA, and without prompt and aggressive treatment these patients may rapidly decline," the researchers added.
The study is published in the journal Women's Health.