How does Rh negative factor affect pregnancy?


The feeling of having a baby inside the womb is a bliss and unique for every mother. The unconditional love and protection for the baby comes natural to expectant mothers and it is necessary to understand the possible medical conditions during pregnancy. If you are Rh negative, know the effects of Rh factor in pregnancy.

What is Rh factor?

Just like ABO blood grouping, there is also Rh factor which is determined by a protein, antigen D present on the surface of red blood cells. If antigen D is present, it is termed as Rh positive and if the antigen is absent, it is termed as Rh negative. Hence the blood groups of individuals are determined as positive or negative.

How it works?

Rh factor affects only if the mother is Rh negative and the baby is Rh positive (genes inherited from the Rh positive father). If the baby’s blood enters the mother’s bloodstream, it will trigger an immune response. Due to the presence of D antigen in the baby’s blood cells, the mother’s immune system treats it as a foreign body and creates antibodies to fight against the antigen. This is called ‘sensitising event’ which may cause anaemia or even birth defects in the newborns.

Effect of Rh sensitising in pregnancy

The mixing of mother and baby’s blood is most likely to happen during delivery, so it has no threatening effect on the first born. However, if the second baby is also Rh positive, the antibodies developed during the first pregnancy will rush through the placenta and attacks the baby’s blood cells. This may result in numerous medical conditions such as anaemia, heart failure and fluid retention (if anaemia is severe), cerebral palsy, speech problems etc.

How to prevent it?


During your ante-natal appointments, the Rh blood group will be tested and given anti-D injection, if the baby is Rh positive. The anti-D injection will prevent the formation of antibodies that affects the fetus. Thus, you and your baby will be safe from Rh sensitizing event during and after pregnancy.



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