Fig. 4

Hypothesis on the exacerbation of headache in the supine position in reversible cerebral vasoconstriction syndrome. In RCVS, cerebral perfusion is decreased by the constriction of the small cerebral arteries. To compensate for the decreased cerebral perfusion, the leptomeningeal arteries are dilated, resulting in severe headaches. In the early postpartum period, higher sympathetic activity due to aortocaval compression by the gravid uterus in the supine position contributes to dysregulation of the small cerebral arteries and exacerbates headaches