This case report describes a 30-year-old woman who developed an acute spontaneous subdural hematoma (SDH) after receiving intraspinal anesthesia for a cesarean section, presenting with only headache as an initial symptom. The purpose of the report is to emphasize the importance of considering acute spontaneous SDH as a potential complication of intraspinal anesthesia in patients presenting with headache, even in the absence of other neurological deficits, and the need for prompt recognition and management of this condition, as early intervention can significantly improve outcomes. The report also highlights the importance of informed consent and patient education about the potential risks and benefits of different types of anesthesia during cesarean section. The discussion includes the pathophysiology of subdural hematoma after spinal anesthesia, potential causes of severe headache, and the importance of distinguishing between neurological symptoms of intracranial hypotension, post-dural puncture headache (PDPH), and subdural hematoma. The patient underwent burr hole evacuation after the subdural hematoma converted completely to chronic, with no neurological abnormality or recurrence till now.