[In utero death of one twin and cerebral complications in the surviving twin].

When one of two twin foetuses dies in utero, the survivor may present with a number of abnormalities, including severe lesions of the nervous system. These lesions are of vascular origin and seem to be due to tissue emboli from the dead foetus. Monochorionic pregnancies are those at the highest risk of this pathology. The surviving twin must be examined both clinically and by ultrasonography.