Yahoo Lifestyle Rhesus disease
As soon as I diagnose a new pregnancy I run a battery of blood tests, which include a request for the woman’s blood group and antibodies. There are four basic blood groups: O and A (both common) and B and AB (both less common). These refer to the red blood cell types. Red cells carry oxygen, so they’re important, but the type of blood cell you have is irrelevant to your health. Then, for your blood-group type you’ll either be positive or negative. This refers to your Rhesus type – whether you have something called the Rhesus (Rh) antigen or not. This antigen is just a protein that sits on the outside of your red blood cells and doesn’t do much! About 85 per cent of the population is Rh positive.
Um, so what does all this mean?
We test for your blood group because if you’re Rh negative, there’s a chance your baby might develop Rhesus disease. Also known as haemolytic disease of the newborn, or blue baby syndrome, the condition results from your own disease-fighting antibodies crossing the placenta and attacking the baby’s ‘foreign’ red blood cells. This can make the baby jaundiced and anaemic. In severe cases, the baby can swell up and even die. Serious stuff in theory, but in reality we can manage the problem easily.
How does Rhesus disease happen?
Rhesus disease is only possible if…
You’re Rh negative and
Your baby is Rh positive and
‘Sensitisation’ has previously occurred.
Sensitisation happens when you’re Rh negative and are exposed to Rh-positive blood. Untreated, you’ll have had an immune reaction to the positive blood, which means your body will have formed antibodies that will attack any future Rh-positive cells you encounter.
The most common way you would’ve been exposed to Rh-positive blood is through a previous pregnancy (if your baby was Rh positive) – even if that pregnancy was miscarried or terminated. In 86 per cent of cases, the exposure happens during labour.
How can it be stopped?
If you’re Rhesus negative, your carers will know very early on and treatment will be at hand. A side-effect-free serum injection is available that will stop you producing the antibodies that attack Rh-positive blood. This injection is known as anti-D and contains something called ‘anti-D gamma globulin’. It’s obtained from Rh-negative blood donors, so next time you pass your local blood donation centre, give a little nod of thanks!
You’ll be given this anti-D injection at 28 weeks, 34 weeks and then within 72 hours of the birth to stop you forming the antibodies. Apart from these routine injections, you’ll also get anti-D if you have a vaginal bleed earlier in the pregnancy or if you have an invasive test such as chorionic villus sampling (CVS). Rh-negative women who have a miscarriage after 12 weeks, a procedure after a miscarriage at any stage or termination at any stage of pregnancy are also usually offered anti-D.
As for how much, research has shown that the more blood lost during birth or the more traumatic the event that sees bub’s blood escape into yours, the more anti-D you need. So you’ll have a blood test called the Kleihauer test to determine exactly how big the blood loss was and the dose will be tailored respectively.
The advent of anti-D back in 1969 has revolutionised the Western world and as a result we don’t really see Rhesus disease in newborns anymore. It’s a big problem in developing nations, though, where babies still sadly die from the condition.
We do watch Rh-negative mums closely and if we’re concerned that the baby might have been affected there are ways of fixing him, including a blood transfusion, but take heart: this is really rarely needed and if you’re Rh negative, things should work out fine.
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