Eli5: How does a RhoGAM shot work during pregnancy?

Question

I understand **what** the RhoGAM shot does, that it tells the mother’s immune system to not attack the baby if the baby has a different blood type. But **how** does that happen?

I understand how a flu shot works, but that feels like the total opposite

In: 3

Answer 1

Adding to what u/GalFisk said, which was a great explanation. Because its a dose of outside antibodies (not a vaccine which teaches your body how to make something new) those antibodies will either get used up or degrade over time (approx 13 weeks) RhoGAM is therefor given any time there is a chance the mother could be exposed to fetal blood, which can be more than once in each pregnancy (bleeding, surgery, birth, etc)