Are you Rh incompatible?

Expectant mothers should be cautious about being Rh incompatible, writes Dr Rishma Dhillon Pai

As one may already be aware, four main blood group types exist: A, B, AB and O. Determined by the genes, an individual’s blood group is inherited from his/her parents. Additionally, a protein known as the Rh Factor is either present as Rh-Positive (+) or absent as Rh negative (-) therefore creating eight common blood group types.

The Rh or ‘Rhesus’ factor, is an inherited protein found on the surface of the cell membranes of red blood cells. If your blood contains the protein, you are Rh-positive, if it does not, you are Rh-negative. However, having the Rh blood type is a normal condition and does not imply that one has a disease or that it could generally alter your health.

Being an Rh-negative female could affect pregnancy. A pregnant woman with the Rh-negative blood type would require particular care, especially if the baby the woman is carrying is Rh-positive, as this causes Rh incompatibility. This condition does not affect the mother’s health, however, being cautious of her Rh-negative status is important as it can impact the baby she is carrying.

Rh incompatibility occurs when the mother’s body reacts to the Rh-positive blood of her baby by producing antibodies. Especially in her second pregnancy with an Rh-positive baby, her body produces antibodies instantly. For an Rh-positive baby, these antibodies can cause damage to the baby’s red blood cells after they cross the placenta. Red blood cells are essential for oxygen to be carried throughout the body. In such cases, it could cause life-threatening conditions like anaemia where the red blood cells are damaged faster and the ability of the baby’s body to replace them is difficult. It could also lead to jaundice, heart failure, liver failure and could be life-threatening to the baby.

The condition can be determined by a simple blood test of the mother — the Indirect Coombs test. This will help detect whether the blood contains the cell-destroying antibodies, and your doctor will advise appropriate action. If the mother is Rh-negative, and the father is Rh-positive, an immunoglobulin injection can be administered to the mother to prevent her body from producing Rh antibodies. This can be given at 28 weeks of pregnancy and after delivery if the baby is found to have a positive blood group. These measures can protect the baby very effectively.

(The author is a consultant obstetrician & gynaecologist.)