Pregnant women are most likely to have primary headaches, such as migraine and tension-type headaches, which can be diagnosed and treated without brain imaging. Primary headaches may even start de novo during pregnancy, especially in the first few months. However, when the headache occurs late in pregnancy or in the peripartum period, secondary causes of headaches need to be considered and evaluated by brain and/or vascular imaging, generally using magnetic resonance techniques. There is considerable overlap between the cerebrovascular complications of pregnancy, including preeclampsia/eclampsia, posterior reversible encephalopathy syndrome (PRES), reversible cerebral vasoconstriction syndrome (RCVS), and both hemorrhagic and ischemic strokes; although, their imaging may be distinctive. Imaging is necessary to distinguish between arterial and venous pathology causing headache in the peripartum patient, as there can be similar presenting symptoms. Mass lesions, both neoplastic and inflammatory, can enlarge and produce headaches and neurological symptoms late in pregnancy.
