The significance of anti-Kell sensitization in pregnancy

In a 10-year period, 407 of 350,000 pregnancies showed maternal anti-Kell allo-immunization, i.e., an incidence of 1.16 per 1000 pregnancies. About 88% of Kell immunized women gave a history of previous transfusion. There were 51 pregnancies with Kell positive partners (all Kk) resulting in 10 Kell positive babies, of whom six had a positive direct antiglobulin test (DAGT). There were two stillbirths due to haemolytic disease of the newborn, when the maternal anti-Kell titres were 1/256. One baby was severely anaemic and given a top-up transfusion, and two babies were jaundiced and given phototherapy. A policy for management of Kell sensitized pregnancies is outlined, based upon maternal anti-Kell titre and where appropriate fetal blood sampling.