Arteriovenous malformations of the cerebral circulation that rupture in pregnancy.

Arteriovenous malformations (AVMs) have a poorly defined natural history, more so in the pregnant population. Presentation during the pregnancy is usually as a result of haemorrhage following rupture. Whether pregnancy alters the natural tendency to rupture remains controversial, but empirical data suggest that this is the case. The most important complication following rupture in pregnancy is the possibility of a subsequent re-haemorrhage. In those patients with high operative risk or inoperable lesions, a conservative management course should be adopted during the pregnancy allowing stereotactic radiosurgery or embolisation options to be pursued after delivery (see Management algorithm). Precautions during labour are recommended, biased towards caesarean section. In those patients in whom a lesion is deemed operable (low risk), surgery may improve the risks of poor outcome provided treatment risks are low. Factors such as AVM morphology, local expertise and support facilities (including those for endovascular therapy) are essential considerations if outcome is to improve on the natural history of the condition. Preoperative endovascular embolisation can be included when considering surgical excision.