The influence of pregnancy on the course of hereditary spherocytosis was investigated in 21 women during their 44 pregnancies. Fourteen pregnancies were followed up directly, 30 were evaluated from anamnestic data. In the majority of investigated women with hereditary spherocytosis pregnancy caused no prob- lems. When complications developed, they were not serious as a rule. Only about one third of pregnancies in non-splenectomized women developed anaemia or anaemia deteriorated. In the latter enhanced haemolysis participated. In splenectomized patients the incidence of complaints was minimal.

        Key words: Hereditary spherocytosis - Deficiency of red cell protein membranes - Pregnancy.