Why Your Blood Type Matters When You’re Pregnant

You may not know your blood type before you get pregnant, but you’ll find that it becomes very important once you become pregnant. It doesn’t matter if your blood type is A, B, or O, but the Rh factor, short for Rhesus factor, does. Your blood type may be followed by a positive or negative, which determines if you’re Rh positive or negative. The providers at Darin L. Weyhrich MD explain more about the Rh factor and why it matters so much when you’re pregnant.

Why the Rh factor matters

We perform a test on your blood to determine your blood type and whether the antigens are positive or negative. Antigens are protein markers that are either present on your cell or not.

If your blood type is positive, it means you’re Rh positive, and if your blood type is negative, you’re Rh negative. An Rh-negative woman may give birth to an Rh-positive baby, which causes an incompatibility that can lead to serious health conditions for the baby, which is why we pay close attention to Rh factors as part of our obstetrics servies.

Blood type incompatibility

In addition to incompatible antigens, your blood type may also be incompatible with your baby’s. For example, if your blood type is A and your baby’s is type O. This is called ABO incompatibility, which can cause problems. 

If the two different blood types mix, your blood may develop antibodies that fight against the baby’s blood. But we can neutralize this condition with an injection of Rhogam to prevent potential complications to your baby’s health. This shot is usually given around 26-28 weeks of pregnancy, which provides temporary antibodies to protect your baby.

What Rh factor can affect

If you are Rh-negative and you don’t get the Rhogam shot, your baby may develop:

• Jaundice
• Anemia
• Low muscle tone

If you have Rh factor incompatibility, your baby may lose more blood cells than they can produce, leading to lack of oxygen.

The truth about Rh factor incompatibility

Rh factor incompatibility is relatively rare, and most pregnancies aren’t affected thanks to regular OB/GYN prenatal screening.

Your blood type also matters when if you need to recieve a blood tranfusion while you’re pregnant — a rare emergency, but one to keep in mind.

If your Rh factor is incompatible with your baby’s, and you choose not to receive a Rhogam shot, you may experience complications during delivery, including the possibility of needing exchange transfusions that replace your baby’s blood with healthy donor blood and help them overcome jaundice more quickly.

Your baby may also need the assistance of a bilirubin light tol help the liver to clear out jaundice more quickly.

If you have Rh factor incompatibility, don’t worry — we monitor you and your baby closely and takes steps to ensure your health. Contact the staff at Darin L. Weyhrich, MD, if you’re concerned about Rh factor or schedule an appointment online.