We present a case of a pure acute subdural haematoma of the convexity from a ruptured communicating anterior aneurysm, in a full-term pregnant woman. She was managed in emergency as follows: cranial computed tomography, general anaesthesia, caesarean section, cerebral angiography, evacuation of the subdural haematoma and clipping of the aneurysm. The outcome was excellent. Pure subdural haematoma from ruptured aneurysm, with little or no subarachnoid, intraventricular or intracerebral haemorrhage is very rare. We discuss the treatment of such a haematoma and discuss the other causes for spontaneous subdural haematomas. Our observation stresses the need for a high-performance technical plate in the management of ruptured aneurysms, but also for the importance of a correct clinical diagnosis of minor leaks by the general practitioners who decide on the hospitalization.