What Is the Rhesus (Rh) Factor and What Could It Mean for My Pregnancy?

There’s lots of public health information out there about how important it is for expectant mothers to eat healthily and avoid drinking alcohol or taking drugs during their pregnancy, but what can you do about things you can’t control -- like the status of your Rh factor in your blood?

Our OB/GYN specialist Brandon M. Lingenfelter, DO, PhD, explains the Rh factor so that you know how it can affect your pregnancy and your baby. 

What the Rh factor is

You may be aware of your blood type, whether it’s O, A, B, or AB. But there’s something else called the Rhesus (Rh) factor, which is a type of protein found on the outside of your red blood cells. Whether your Rh factor is negative or positive plays a role in how your immune system responds to perceived threats. 

Your Rh factor is genetic.  Most women and men in the United States (about 85% of the population) are born with the Rh protein and are referred to as being Rh-positive. The issue with Rh factor and pregnancy happens when there is a mismatch between the Rh factor status of the mother and the baby. If the mother is Rh-negative and the baby is Rh-positive, this is called Rh incompatibility

Rh incompatibility can be life-threatening for the baby

Rh incompatibility health issues occur when something happens that causes the mother’s blood to come into contact with the baby’s blood, which is known as Rh sensitization. At this point, the mother’s immune system perceives the baby’s blood as a threat and develops antibodies that attack and destroy the baby’s red blood cells via the placenta. This can cause hemolytic anemia in the baby, which leads to jaundice, heart and liver failure, and in severe cases, brain damage, or even death. 

Prenatal testing is important

The good news is that Rh incompatibility can easily be detected through blood tests. Rh factor testing is a routine part of prenatal care, and is typically one of the first tests conducted during your first prenatal appointment. If the test results show that the mother is Rh-negative, then the doctor performs a follow-up blood test to see if antibodies are present. If no antibodies are detected, then the father gets tested to determine his Rh factor status.

Rh incompatibility is treatable

The most important thing to keep in mind is that Rh incompatibility is treatable. If the mother is Rh-negative and it’s detected earlier during the pregnancy before any possible sensitization, the doctor prescribes an injection of Rh immunoglobulin for the mother, which prevents her body from producing antibodies. The injection will need to be repeated for every pregnancy or miscarriage as well as after any procedures where mother’s and baby's blood could potentially mix, such as amniocentesis.

You don’t need to worry about the Rh factor, as we take care of making sure you’re tested, and if there’s Rh incompatibility, we provide Rh immunoglobulin treatment to make sure your baby is protected, as well as any future pregnancies. 

If you’re pregnant or wish to become pregnant, make an appointment to see Dr. Lingenfelter at our practice in Princeton, West Virginia. Book your appointment online or call our office today.

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