Following on from our magazine article “How Much is Too Much?” in the October issue, we have been looking at other pregnancy complications throughout last month here on the beijingkids blog. In the last of this blog series we explain rhesus disease.
What is rhesus disease?
Also known as Rh incompatibility, Rh disease, and rhesus isoimmunisation, rhesus disease is a condition that causes a pregnant woman’s blood to destroy the blood cells of her unborn child. It occurs when the mother has rhesus-negative blood (Rh-negative, i.e. A-, B-, O- or AB- blood types), but the fetus’ blood is Rh-positive.
In such circumstances, if red blood cells pass from child to mother through the placenta, it triggers the release of antibodies by her immune system, which treats the baby’s blood as a foreign substance. If these antibodies pass back to the unborn child they will begin attacking the fetal blood cells. Although the mother is unharmed, the consequences of the disease can vary from mild jaundice to fetal heart failure, depending on the mother’s immune system and the speed with which it is diagnosed.
The disease is however, both preventable and, in most cases, easily treated.
Who’s at risk?
Around 15 per cent of women have Rh-negative blood, though this figure is slightly higher for Caucasians and significantly lower for people of Asian origin. It is when the father is Rh-positive or Rh-unknown then there is a risk that incompatibility with the baby can occur.
Furthermore, the disease only occurs when the mother has previously been exposed to Rh-negative blood, as it takes time for the mother’s body to develop these antibodies. As such, firstborn children will not usually be affected, though there is a higher risk for any subsequent Rh-incompatible pregnancies, because antibodies can be produced immediately. Mothers who have had a previous child, miscarriage or abortion are therefore more likely to be affected by the disease.
What are the symptoms?
There will be no immediate symptoms in the mother during pregnancy, though the routine blood checks and ultrasound scans can usually reveal if rhesus disease has been developed by the unborn baby. The main symptom is anemia which may give the baby thinner blood or internal swelling
But in some cases, if the condition is not particularly severe, the symptoms may first appear in a newborn baby, as it can still carry the mother’s antibodies for a number of months after birth. The following symptoms may be apparent at upon birth, but can develop as long as three months after.
- Jaundice: a yellowing of the skin and the whites of the eyes. It is caused by a substance called bilirubin, the chemical that is produced when red blood cells are destroyed.
- Lethargy, or lack of energy.
- Low muscle tone (hypotonia), which could manifest itself as the baby appearing “floppy”.
- Pale skin
- Increased breathing rate
- Poor feeding
What is the treatment?
In about half of rhesus disease cases, the symptoms are mild and easily treatable.
If it is a mild case, the baby can be treated after birth with blood transfusions, electrolytes and simply keeping hydrated. The aforementioned harmful substance bilirubin may also be treated with phototherapy, where the baby is kept under special lights immediately after birth.
Blood transfusions can take place in utero in very severe cases, though this is incredibly rare.
There is another related issue that people in Beijing should also be particularly aware of. We have heard stories of the capital’s hospitals not having stores of certain rare blood types, which can have unexpectedly terrifying consequences. In one case posted on the Beijing Mamas Yahoo Group (see here – login required) a mom-to-be with O- blood found out just 11 days before her caesarean section that the hospital did not have any reserves and would be unable to obtain any in time. She had to resort to the kindness of strangers on the forum to solicit a blood donor.
So if you are found to have a rare blood type you should assume that your chosen hospital has the supplies you may need in an emergency. In the case above, the mother in question only found out after insisting a number of times that checks were made.
What can you do to reduce the risk of developing it?
Rhesus disease is preventable. The first step is to determine whether you are Rh-negative, which can be done with a simple blood test. This should happen at your first prenatal visit and you should ensure that it does. If it is found that you are RhD negative you will undergo a second blood test to determine whether your blood contains anti-D antibodies, in other words, whether you have been exposed to Rh-positive blood.
If you are considered at risk of developing the disease, you will be closely monitored for the rest of your pregnancy. Although blood types are inherited, there are preventative treatments which can stop the serious effects of the condition.
If it is thought that any of your baby’s RhD antigens have entered your body at an early stage of pregnancy (as a result of bleeding or abdominal injury for instance) you will be offered an injection of anti-D immunoglobulin which will prevent the production of the mother’s antibodies. If not, you should still be routinely administered with it in your third trimester when it is most likely that blood will pass through the placenta.