Updated: Dec 20, 2020
What is Rhesus (Rh) blood type?
We inherit our blood types (A, B, O and AB) from our parents. These blood types are further categorised based on Rhesus status (Rh). If the Rh protein is present on your red blood cells, you are Rh positive. Conversely, if Rh protein is absent, you are Rh negative.
Why is testing for Rhesus (Rh) status important in pregnancy?
Special care is needed if you are Rh NEGATIVE. If your baby is Rh POSITIVE, there is a chance of your baby's blood mixing with yours during pregnancy and delivery. In such circumstances, your immune system is triggered to produce Rh antibodies against the Rh positive blood cells. This will not affect the first pregnancy, but may trigger a crisis for subsequent pregnancies.
For subsequent pregnancies, these Rh antibodies cross the placenta and may proceed to destroy your baby's blood cells, causing "Haemolytic Disease of the Newborn" (HDN). This causes jaundice, severe anaemia or even brain damage in the baby.
How can I avoid HDN of baby?
To reduce the impact of such immune response, routine anti-D immunoglobulin prophylaxis injection (Rhogam®) is administered at 28th week of pregnancy to all Rh-negative pregnant mothers. This is to prevent your body to produce Rh antibodies. A second dose is given after delivery if your baby is Rh positive.
What is the risk of Rhogam injection?
Rhogam® injection is safe in pregnancy. The main disadvantage is that it is costly.
Can I test for Rhesus status of my baby during pregnancy?
Yes, you can! RHENE™ blood test, a non-invasive prenatal test (NIPT) to predict your baby’s Rh status from maternal blood is available. With a simple blood test, RHENE™ analyses your baby’s DNA circulating in your bloodstream. This test is done from 24th weeks of pregnancy and is 99% accurate. Speak to your obstetrician about the test.
RHENE™ test is based on recommendations by the 2016 UK National Institute for Health and Care Excellence (NICE). Countries like UK and Australia have implemented NIPT for foetal RhD testing into their clinical practice.