I am Rhesus negative
There are different blood groups in humans. Most people have blood group that is Rh-positive.
Rh incompatibility occurs when a pregnant woman has Rh-negative blood and the fetus has Rh-positive blood. If the fetus's Rh-positive blood enters the bloodstream of a woman with Rh-negative blood, the woman's immune system may recognize the fetus's red blood cells as foreign and produce antibodies. This may cause a problem in a future pregnancy. 22
For pregnancies up to 63 days (9 weeks), there is no evidence that any problem related to blood groups can occur this early in pregnancy. So there is no need for a woman to get any injection or treatment related to the blood types. 1
For women that are more than 9 weeks pregnant and know that they are Rh-negative, the woman should get an Rh-immunoglobulin injection the same day they take the mifepristone or misoprostol or maximum up to 72h after the abortion to avoid Rh incompatibility.22