How safe is your pregnancy when you are Rhesus negative?

Pregnant mother looking at photo of her ultrasound scan

How safe is your pregnancy when you are Rhesus negative?

By Siti Marlina Saleh, Lecturer, School of Allied Health Sciences

Blood Group

Do you know your blood group? Some people are A positive, some are A negative and so on. The “A blood” group refers to ABO blood grouping while the positive and negative refers to Rhesus blood grouping. You are Rhesus positive when u have the D antigen (protein) in your red cell surface and you are Rhesus negative when you don’t have it.

The Rhesus grouping plays an important role in determining whether your baby will suffer from hemolytic disease of newborns, HDN (mother’s antibodies attacking fetus red cells).

The Risk

When a Rhesus negative woman marries a Rhesus positive man, there’s a possibility that their baby is either Rhesus positive or negative. Babies may suffer from HDN when the Rhesus negative woman carries a Rhesus positive baby. The D antigen in the baby’s RBC may look foreign to the mother’s immune system. In order to protect the mother against foreign substances i.e. the baby’s D antigen, anti-D produced and attacking the baby’s red cell that carry the foreign antigens. This causes lysis (breakdown) of the baby’s red cells and can lead to HDN i.e. the baby having anemia due to RBC lysis. The suffering baby needs treatment based on how much his or her red cells have lysed. On the other hand, Rhesus negative babies will not develop HDN since the absence of the D antigen in their red cells will not stimulate the mother’s immune system.

Good News – There is Hope for a Safe Pregnancy

Does this mean that Rhesus negative women cannot conceive? Does this mean that Rhesus negative women cannot marry Rhesus positive men? With the advancement of medicine, Rhesus negative women can conceive and marry Rhesus positive men since there is a preventive measure against the development of HDN. The RhoGAM injection that is given to pregnant mothers is efficient in preventing the production of anti-D. This injection, together with the close monitoring of both mother and baby, will minimize the severity of HDN.