Stroke associated with pregnancy or puerperium is rare, but represents an important problem for women of childbearing age. We herein report a case of subarachnoid hemorrhage (SAH) due to suspected lateral posterior choroidal artery (LPChA) dissection during delivery. A 34-year-old woman developed deterioration of consciousness during delivery at a maternity clinic. Her Glasgow Coma Scale score was E3V3M6. She was sent to our hospital after 12 hr, where CT revealed SAH with intraventricular hematoma. Radiographic examinations showed contrast pooling on the left LPChA. Repeated angiography showed enlargement of the contrast pooling, which indicated pseudoaneurysm. It also showed a relatively clear but stenosed LPChA communicated with the lesion which could not be recognized in the angiography on day 0. This stenosed LPChA indicated arterial dissection. Therefore, endovascular parent artery occlusion was performed on day 11. Determining the exact extent of dissection was difficult because the LPChA was extremely narrow. Occlusion of the posterior cerebral artery was needed to achieve complete hemostasis, which, however, resulted in infarction of the medial temporal and occipital lobes. At the time of final follow-up 3 years later, the patient was alert and completely independent, but showed persistent incomplete homonymous hemianopsia. We reported a rare case of SAH from suspected LPChA dissection during delivery. Repeated angiography provided information about the source of hemorrhage and definite diagnosis, which opened the way to treatment. It is also important to recognize the difficulty in identifying the exact extent of dissection when treating dissections of small arteries.