Thrombocytopenia is a common haematological abnormality in pregnancy which has important implications for both mother and fetus. It may occur as part of the pathophysiology of pregnancy itself, but in many cases pregnancy is superimposed on a background of haematological disease. Failure of platelet production remains a difficult and dangerous problem to manage while the outlook for non-immune platelet destruction has improved as a result of a clearer understanding of the haemostatic changes taking place in the pregnant woman. Immune-mediated thrombocytopenia is now also better understood because of recent advances in antibody detection and quantitation but it has been difficult to translate this new knowledge into the planning of well considered treatment strategies. The administration of high-dose ivIgG to either mother or fetus shows promise as a new and safer method of managing delivery and neonatal life in autoimmune and alloimmune thrombocytopenia but further evaluation is necessary before the indications for giving ivIgG are clear. Close cooperation between obstetricians, haematologists and scientific staff is essential if the best treatment for the thrombocytopenia of pregnancy is to be given.