[Thromboembolic events, abortions and a sick infant--unusual presentation of a vitamin deficiency].

Homocysteine is a risk factor for the development of thromboembolic disorders and vascular diseases. Furthermore, complications during pregnancy have been ascribed to hyperhomocysteinemia. We report on a pregnant woman being substituted by high doses folic acid for hyperhomocysteinemia. Thereby, the underlying pernicious anemia was masked. After birth, the neonate was exclusively breastfed. At the age of 5 months, the infant had to be admitted to hospital due to severe vitamin B(12)-deficiency. Using parenteral vitamin B(12) substitution, homocystein levels of the mother normalized and the infant throve and prospered again.