The incidence of stroke (both ischemic and hemorrhagic) in pregnant and peripartum women is three times age-matched controls. This increased risk is mostly in the 3rd trimester and up to 16 weeks postpartum.
Consider other causes of stroke: posterior reversible encephalopathy syndrome (PRES), reversible cerebral vasoconstriction syndrome, cerebral venous sinus thrombosis and cardioembolic stroke from peripartum cardiomyopathy.
CTs carry some risk due to the ionizing radiation, but with abdominal and pelvic shielding the exposure to the fetus is very low. MRIs do not carry that risk, but Gadolinium is absolutely contraindicated in pregnancy as it deposits in fetal tissue.
Pregnancy is a relative (not absolute) contraindication for tPA.
References
Majerisk JJ. Inherited and Uncommon Causes of Stroke. Continuum 2017;23(1):211–237.
