Effects of rhesus disease on pregnancy, child survival

About 90-95 per cent of Nigerians are RhD-positive (Rh blood group, D antigen). The remaining five per cent are RhD-negative and account for Rhesus disease.

There is need to increase the level of awareness by mothers, fathers and members of the community in general about the importance of knowing their blood groups and the rhesus factor. This could help reduce or prevent cases of foetal mortality.

On several instances, I have seen patients who had come for treatments of different ailments and had made requests for blood groups to be added to the list of investigations requested by their doctors. On occasions when I asked to know why they made the requests, they rarely mentioned Rhesus blood disease as one of the reasons. Indeed, while some may say they just wanted to know, some will say it’s simply because of emergency cases requiring blood donation or transfusion.

A popular Chinese proverb says “The beginning of health is to know the disease.” This signifies the importance of awareness of this condition — just like other health issues. There are different types of human blood. The four main blood groups are: A, B, AB and O. Each of these blood groups can either be: RhD positive or RhD negative.

The RhD is a protein that is either present or absent on the surface of the red blood cells.  This is indicated by a plus sign +ve or a minus sign -ve. An example is the blood type O+ve, which means that the blood is type O and each blood cell has RhD; while O-ve means that the blood is type O and each blood cell has no RhD.

The RhD negative gene is recessive, while the RhD positive gene is dominant. This means that

there is a greater chance that a RhD-negative mother will conceive a  RhD-positive  baby if  the  father is RhD-positive.

A simple blood test can tell if a woman is Rh-negative. Every woman should be tested at her first prenatal visit, or before pregnancy, to find out if she is Rh-negative. A mother who is Rh-positive or the baby is not affected by this disease.

The Rh-negative mother’s body considers the RhD-positive cells a threat and mounts an    immune system response. Her immune system makes antibodies (called anti-D antibodies) against the RhD-positive blood cells. These antibodies could pass through the placenta and harm the developing baby’s red blood cells.

The first baby is usually safe, because baby’s and maternal blood usually do not mix until delivery. If the second baby is also Rh-positive, there is a risk that the antibodies will attack her blood cells and cause problems.

RhD-negative women should also be vaccinated if there has been any possibility of foetal blood

entering their bloodstream. For example, vaccination should be considered after miscarriage, abortion, amniocentesis, abdominal trauma during pregnancy, and manipulation of a breech presentation during delivery.

Unfortunately, most young ladies who may have been exposed to abortion from quacks and unorthodox medical facilities don’t get their blood groups done before such services are rendered. They may also have been ‘sensitised’ without knowing it. Such Rh-ve ladies are at risk of losing their first Rh +ve babies because of previous sensitisation.

Complications

Rh disease destroys foetal red blood cells. It was once a leading cause of foetal and newborn deaths. Without treatment, severely affected foetuses often are stillborn. In the newborn, Rh disease can result in jaundice (yellowing of the skin and eyes), anaemia, brain damage, heart failure and death. It also affects the mother’s mental state, as most mothers are depressed after losing a baby.

Some foetal deaths resulting from this disease in the olden days and in the villages are said to be as a result of Abiku or Ogbanje and, in some instances, associated with witchcraft.

Prevention

Prevention is the best form of treatment. A vaccine against Rhesus disease has been available for

years.The vaccine helps to prevent the mother’s immune system from making anti-D antibodies

and offers protection for future pregnancies against RhD disease.

The vaccine, which contains an anti-D immunoglobulin (Rhogam) is given by intramuscular injection during pregnancy, mostly at the 28th week of gestation and after delivery of a Rh positive baby. It must be given within the first 48-72 hours after delivery.

The vaccine is expensive, and that’s why, during antenatal care, RH-ve pregnant women are counseled on the need for the vaccine and informed early to prepare to ahead for it, so that it will not be a financial burden during delivery or upon sensitisation.

Treatment

Treatment of the baby is based on how severe the loss of red blood cells (anaemia) is. The preferred medical treatment for a baby born with severe rhesus disease is blood transfusion. The blood is exchanged until the baby’s blood has been completely replaced with healthy donor    blood.

The transfusion also removes maternal anti-D antibodies, which prevents damage to the baby’s new red blood cells.

If the baby’s anaemia is mild, more testing than usual is needed during the pregnancy. The baby may not need any special treatment after birth, but he must be monitored during the neonatal period.