A pregnant woman with a mechanical prosthetic mitral valve was anticoagulated with low-molecular-weight heparin in the first trimester followed by warfarin until 36 weeks' gestation. She was then switched to intravenous unfractionated heparin infusion to allow for regional anesthesia in anticipation of vaginal delivery. She developed severe headache on hospital day 2 that was refractory to pain medications. Cranial imaging demonstrated a large subdural hematoma with midline shift. She delivered a healthy baby girl by cesarean section. Eventually, symptoms and intracranial abnormalities resolved over time. In conclusion, subdural hematoma is a relatively rare complication that requires multidisciplinary management plan.