How Do I Know if I’m Rh Negative or Rh Positive?

What does it mean if I'm Rh negative or Rh positive? Do I have to get tested?
profile picture of The Bump Editors
ByThe Bump Editors
Updated
Mar 2017
Hero Image

At your first prenatal appointment, your OB will take blood for a long list of screenings. One of them will be to determine your blood type. You may already know if you’re  type A or O, but what’s important during pregnancy is whether or not you’re “positive” or ”negative.” Your OB will test your blood for Rh, a protein present in about 85% of the population. If you’re  Rh-negative and the father is Rh-positive, the fetus can inherit the Rh factor from the father. This makes the fetus Rh-positive too. Problems can arise when the fetus’s blood has the Rh factor and the mother’s blood does not. So, baby is “positive” but you are “negative”. If this happens, it’s possible for you to develop antibodies to your baby, in essence your body will think it’s allergic to baby. To prevent any complications,  you’ll need injections of a medication called RhoGAM at 28 or 29 weeks and within 72 hours after delivery to prevent problems.

Plus, more from The Bump:

Related Video

Should I Get Genetic Testing?

Jennifer L.W. Fink
Registered Nurse

What Is RhoGAM?

The Bump Editors

What Is the Neural Tube?

Sharon Phelan, MD
OB-GYN

What Is Fundal Height?

The Bump Editors

A Pap Smear Early in Pregnancy Could Reveal Genetic Disorders

Anisa Arsenault
Associate Editor
Published
11/07/2016
Advertisement