A 35-year-old woman with severe Glanzmann's thrombasthenia became pregnant involuntarily. As a late abortion might cause a bleeding as severe as a delivery, legal abortion was not considered indicated. Treatment with ordinary platelet concentrates was not considered since even HLA-matched platelets did not enhance the platelet function, measured as the aggregability of transfused platelets. This inability was thought to indicate that the patient might have developed antibodies against one of the glycoproteins deficient in this disease. A delivery per vaginam was then preferred because of the local compressing effect. Spontaneous delivery occurred at the end of the 42nd week of pregnancy. The patient delivered a boy with transient thrombocytopenia, probably due to maternal antibodies. To stimulate the haemostasis, uterine contracting drugs were used in unusually large doses and for a relatively long period of time. Tranexamic acid was also given. No haemorrhagic complications could be observed during the puerperium.