[Lithium and pregnancy (author''s transl)]. The problem has been considered of the action of Lithium salts on the progress of pregnancy and on the product of the conception. Lithium can bring about serious troubles in morphogenesis in invertebrate animals. The results obtained in mammals in laboratory experiments differ from species to species but it seems that these animals can be given about 8 to 9 times the levels of Lithium that are used in man without causing teratogenic effects. A statistical review of the children born to human mothers taking Lithium in pregnancy shows up an increase in the incidence of cardio-vascular abnormalities. (7.8% instead of 0.04%). The infants that have received Lithium and have not been anatomically affected show no more developmental problems later than others.