Between January 1975 and June 1989, 240 patients with cerebral vascular malformations were treated at Henry Ford Hospital. In 16 of the patients, the treatment was influenced by pregnancy. Eleven of the patients presented with hemorrhage, four with seizures, and one with hydrocephalus. There were no maternal or fetal deaths in the patients presenting with seizure or hydrocephalus. There were two maternal deaths and one fetal death among the cases presenting with hemorrhage. In the patients with seizure or hydrocephalus, the pregnancy was brought to term and obstetric indications used to determine the time and method of delivery. Hydrocephalus was treated by shunting, and seizures with medication. Antiepileptic drug levels fluctuate in pregnancy and hence were closely monitored to ensure therapeutic levels. Vascular malformations are the most common cause of subarachnoid hemorrhage in pregnancy. The risk of rebleed in the same pregnancy is about 27%. If an arteriovenous malformation ruptures during pregnancy and the patient's condition deteriorates, appropriate emergency surgery should be done. In stable patients, our policy has been to bring the pregnancy to term and then electively perform a craniotomy to excise the arteriovenous malformation.