A conservative estimate is that approximately 5% of pregnancies are affected by de novo headache, that is, new-onset or new-type headache.

(1) Summarize the available literature, which is exclusively neurological, regarding de novo headache during the third trimester of pregnancy and puerperium; and (2) review the common pathologies of pregnancy and puerperium that may be relevant to de novo headache, with focus on the first and second trimester. We obtained the literature through a search of PubMed and references of the retrieved publications, without time limit.

Aneurysmal subarachnoid hemorrhage and idiopathic intracranial hypertension occur at the same rate during pregnancy and puerperium as otherwise, but symptomatic intracranial hypertension due to dural venous-sinus thrombosis is increased during the third trimester and puerperium. Stroke occurrence, whether arterial or venous, does not seem increased during pregnancy and puerperium but when stroke does occur, it is mostly during the third trimester and puerperium. Immediate postpartum headache is commonly either tension-type headache or migraine; when due to spinal-fluid hypovolemia, apart from epidural or spinal anesthesia, a labor-related dural tear should be considered. Of the medical conditions associated with pregnancy, hypothyroidism, anemia, and hypertension may have to be considered as possible causes of de novo headache.

De novo headache during pregnancy is relatively common and almost always leads to neurological referral.