Subclavian artery dissection is usually associated with coexisting aortic disease. Isolated and spontaneous acute subclavian artery dissection is uncommon and rarely reported. In addition, no case of left subclavian artery dissection during pregnancy and early puerperium has been described. We report the autopsy case of a 24-year-old female who died suddenly 3 days after delivery due to a spontaneous left subclavian artery dissection with rupture.