A young pregnant woman with spontaneous carotid artery dissection--unknown mechanisms.

Spontaneous carotid artery dissection in pregnancy has not been reported before. We present a case of a 31-year-old Caucasian woman who was 11 weeks pregnant and presented with neck pain, headache, vomiting and left side Horner's syndrome. Subsequent investigations with MR angiography confirmed spontaneous left internal carotid artery dissection.