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Rhesus factor: How it can affect your pregnancy

Catherine Namutebi, 32, a mother of two, narrates what she went through during her second pregnancy.

Catherine says she was a happy, healthy, expectant mother in perfect shape and took her meds religiously and since she never had complications in the first pregnancy, she was just counting days to receive her second bundle of joy.

However, she says during her routine antenatal visits and tests, the doctor told her blood results indicated that she had a rare condition whereby the baby and her blood groups were incompatible. The doctor continued to explain that her blood group was O-negative and foetus was O-positive.

It is called the Rhesus factor [Rh factor], and it is a serious condition that can cause complications during pregnancy and after delivery for both the mother and the baby if not treated on time. Catherine says it was too much for her to comprehend since she went to the same hospital and was seeing the same doctor during her first pregnancy and nothing like that had come up.

Catherine is one of the few lucky mothers that got to know about the Rhesus factor condition in time, because of her continuous antenatal visits to hospital. Health experts The Observer talked to elaborate more on how this Rhesus factor can affect pregnancy.

Dr Thazethan Kirunda, gynecologist at Bugolobi Medical Center, explains that the Rhesus factor is a protein that can be present on the surface of red blood cells. Most people have blood groups such as type A, B, AB and O, but in addition to that they have Rh factor D and the name of the protein is protein D.

“When one has protein D medically we say you are Rh D positive and when you lack it, we call it Rh D negative.


Dr Kirunda says the Rh factor is a result of genes inherited and passed down by parents to their children, just like blood groups. For example, if a mother is rhesus negative and the father is positive, the unborn child is more likely to inherit the gene from its father. And if both parent are negative the baby will be negative.

Dr Kirunda emphasizes that this Protein D or Rhesus factor can only cause problems if the expectant mother is rhesus negative and the unborn child is rhesus positive and it is scientifically referred to as incompatibility.

For stance if a mother’s blood that is rhesus negative comes into contact with blood of the unborn baby that is rhesus positive through the placenta, this will cause Rh negative blood to produce antibodies that will fight the Rh positive blood in the baby, as if it were harmful.

“The rhesus antibodies that are produced will start to destroy red blood cells faster than the body can replace them and this will cause anaemia,” he says.

Dr Kirunda says red blood cells play an important role in the body; red blood cells carry oxygen to all parts of the body and once these cells are destroyed, the unborn baby will not get enough oxygen hence serious illness. The baby will become anaemic, with yellowing of the eyes and this can also lead to death of the baby due to heart failure.

It should be noted that a person with Rh-negative blood who makes Rhesus antibodies is called “Rhesus sensitized.”

Kirunda says the problems normally do not come in the first pregnancy, but in the later pregnancies.

“It is normally because the baby is born before the mother’s body develops many antibodies and once she does not get treatment and the mother later becomes pregnant again with a Rhesus positive baby, both the mother and baby will be at risk.”

This complication is also responsible for continuous miscarriages after a successful first birth, if the mother does not get treatment for the anormally. 


Dr Nekemaiah Katusiime Arwanire, senior gynecologist and consultant at Mulago national referral hospital, says it is always important for couples to know their blood group before they plan to start family.

“And once one finds out that they are pregnant, one should start antenatal right way and blood type test will be carried out during the first trimester and again during week 28 of pregnancy and it is done to determine the blood group and Rhesus factor.  Knowing this information early will help you plan for a healthy baby, since Rhesus factor plays a very big role in the baby’s health,” Arwanire said.


Dr Arwanire notes that it is mandatory and part of the antenatal package that all pregnant women be tested for blood group – if found to be Rh-negative, mothers are given an injection called the Anti-D to prevent the mother’s immune system from attacking her unborn baby.

The Anti-D [Rh immunoglobulin] shot when given to a Rh-negative mother will mop out all the Rh-positive cells in the blood stream and also stop the production of rhesus antibodies to prevent foetal haemolytic anaemia in later pregnancy

Normally this Anti-D is given to the Rh-negative mothers at seven months of pregnancy then at eight months and also within 72 hours after delivery. It should also be noted that the rh-negative mother will have to take the Anti-D shots in each and every pregnancy of her life.


Complications arising from the Rhesus factor are not so common and it should be noted that about 15 percent of the entire population have this problem so, most hospitals do not have the Anti-D ‘vaccine’ in stock, making it very expensive.

The good news is that the drug is available in the country now, but before patients had to travel all the way to Nairobi to get the vaccine. Reputable pharmacies stock the drug that costs between Shs 200,000 and Shs 300,000 per dose.

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