Blood types are categorized by A, B, and O, and given an Rh factor of positive or negative. A-B-0 and Rh incompatibility happens when a mothers blood type conflicts with that of her newborn child. It is possible for a mothers red blood cells to cross into the placenta or fetus during pregnancy.

Are all blood types compatible for pregnancy?

Although your blood and your babys blood typically do not mix during pregnancy, a minimal amount of your babys blood and your blood could come in contact with each other during delivery. If theres an Rh incompatibility and this happens, your body might produce Rh antibodies against Rh factor.