SUMMARY.Anti‐c is an important Rh antibody that causes haemolytic disease of the newborn (HDN). We have carried out a retrospective analysis of the clinical outcome of pregnancy in 120 mothers with anti‐c. Of these, 100 gave birth to c‐positive infants, of whom 14 had severe HDN requiring exchange transfusion. In all of these, the maternal level was 9.5iu/ml or greater. Of the 29 women with anti‐c levels of 9.5iu/ml or above, in addition to the 14 with severely affected infants, 15 had infants requiring only phototherapy or no treatment. Our observations suggest that when the anti‐c level is below 7.5iu/ml, the fetus is unlikely to be seriously affected and invasive obstetric intervention is unnecessary.Of the 120 women studied, 50% had had a blood transfusion, in most cases for obstetric complications in a previous pregnancy. Although it was not possible to attribute alloimmunization to blood transfusion rather than previous pregnancy in any individual case, this observation points to the value of routine c typing as part of antenatal screening, so that c‐negative blood can