Reversible cerebral vasoconstriction syndrome (RCVS) is characterized by segmental vasospasm and it is often accompanied by either posterior reversible encephalopathy syndrome or stroke. However, other MRI abnormalities have rarely been reported. A 28-year-old woman presented with a thunderclap headache immediately after delivery; MRI showed segmental vasoconstriction and an abnormal signal in the splenium of the corpus callosum. Neuroimaging abnormalities normalized 20 days after the first examination. Only two cases of RCVS with transient splenial lesions (TSL) have so far been reported. Both cases occurred postpartum like ours, indicating that delivery may be a trigger for the development of both TSLs and RCVS.