An assessment of the benefits of prophylactic blood transfusion during 51 pregnancies in women with haemoglobin SS, haemoglobin SC and haemoglobin S-beta-thalassaemia in a retrospective study from 1978 to 1984 has failed to demonstrate any clear conclusions as to their efficacy. Of the transfused patients, 22% developed atypical red cell antibodies and 14% had immediate minor transfusion reactions. Our data show no significant difference in fetal or maternal outcome between those patients who were transfused prophylactically and those who were not. A prospective study to clarify the appropriate place of this important aspect of management in women with sickle cell disease in pregnancy is suggested.