Subarachnoid cyst with hydrocephalus--a complication of mid-trimester amniocentesis.

We report a child with a subarachnoid cyst with hydrocephalus following a mid-trimester amniocentesis. Although fetal trauma is a rare complication, it is important to stress the need to perform amniocentesis under ultrasound control. Children with neurological disease or convulsions of unknown origin in early infancy who are born to mothers who have had mid-trimester amniocentesis should have a CT scan as part of the investigations to exclude this rare but nevertheless important complication.