14 May 2019 Haemolytic disease of the newborn It happens when there is incompatibility between the blood type (ABO or Rh) of the mother and foetus It results from the production of antibodies resulting from the passage of foetal red blood cells through the placenta into the mother’s bloodstream. When one of the possible incompatibilities exists, the mother’s and foetus’s red blood cells have different surface antigens: The mother is Rh- and the foetus Rh+. The mother is O and the foetus is either A or B. When the foetal globules reach the mother’s circulation for the first time , her immune system produces a type of antibody that does not cross the placenta. However, in the event of a second exposure to the foetal red blood cell antigens, the mother's immune system starts rapid, massive production of antibodies of a different type, which cross the placenta and bind to the foetal red blood cells. These red blood cells are then destroyed by the foetus or newborn’s immune system, which gives rise to an increase of bilirubin in the blood, among other problems. ABO incompatibility is more common and less severe than Rh incompatibility. This article was written with the support of physicians and other clinical professionals from the Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.
