What Does It Mean To Be Rhesus Negative During Pregnancy?

I am currently pregnant with my second baby. It feels a bit like doing it all for the first time because my last pregnancy was over five years ago. One of the things I had completely forgotten about was the fact that my blood type is rhesus negative.

It never dawned on me and when I was reminded of it after recent blood tests I had to re-educate myself about what this actually means for my pregnancy. There are certain things I should do and watch out for to ensure that myself and the baby are safe. As it turns out being Rhesus Negative is more of a sensitive issue for a second pregnancy.

During your very first antenatal appointment, it is very likely that you will have blood tests. One of the aims of these blood tests is to determine your health status, immunity and exact blood type. There are four blood groups but within those blood groups your blood will be considered to be “rhesus positive” or “rhesus negative”.

Those who are rhesus positive have a substance known as D Antigen on the surface of their red blood cells and those who are rhesus negative do not. About 15% of people are rhesus negative. There is nothing to be concerned about but there are a couple of things that have to be considered and managed a little bit differently.

The main concern with being a pregnant woman who has a rhesus negative blood type is the fact that your baby could be rhesus positive. This can happen if the baby’s father has a rhesus positive blood type. If some of the baby’s blood enters the mother’s bloodstream the mother’s body can develop antibodies against it.

For subsequent pregnancies, this can mean that the mother’s antibodies begin to attack the baby’s red blood cells. This is where Anti-D comes in.

Anti-D is an injection that is administered to prevent the production of antibodies against the baby and therefore dramatically reduce the risk to the baby. If the baby’s blood cells are attacked it is referred to as being “sensitised” and the baby can be born very poorly and jaundiced.

Your maternity hospital will more than likely schedule you in for a routine shot of Anti-D during your pregnancy. This usually happens between 28 and 30 weeks. You will also be given a shot of Anti-D within 72 hours of giving birth if your baby’s blood type is rhesus positive.

In addition to these routine Anti-D injections pregnant woman with rhesus negative blood should be extremely mindful of any bumps, knocks or trauma to their bump. She should present to the maternity unit in the event of any significant impact as there is a risk of the baby’s blood mixing with her own blood.

Her care team will administer a shot of Anti-D to help control the situation and protect the baby. The same can be said for any vaginal bleeding that may have occurred. The Anti-D injection is safe for both mother and baby.