Rh Incompatibility During Pregnancy
en español: La incompatibilidad de Rh durante el embarazo
Medically reviewed by: Thinh Phu Nguyen, MD
One of the first tests a pregnant woman should expect is a blood-type test. This test checks her blood type and Rh factor. Her Rh factor may play a role in her baby's health, so it's important to know this information early in pregnancy.
What's an Rh Factor?
An Rh factor is a protein found on some red blood cells (RBCs). Not everyone carries this protein, though most do. They are Rh-positive. People who don't carry the protein are Rh-negative.
What if Parents Don't Have the Same Rh Factor?
When a mother-to-be and father-to-be are not both positive or negative for Rh factor, it's called Rh incompatibility.
For example: