Originally Posted by DrRichand1
The only time the mother would have to worry about rh is when she is Rh- and her baby is Rh+. all other combinations don't matter cuz if she's Rh+ then she will not make antibodies.
Since fetal and paternal blood don't mix during pregnancy i'm asumming antibodies made by an Rh- mother during a second pregnancy would cross this barrier. Is that correct?
You meant maternal blood, right?
The reason the first pregnancy isn't usually a problem is because, as you say, fetal and maternal blood typically do not mix before labor. They can, however, mix during labor, which is why subsequent pregnancies can be a problem for Rh- mothers. I'm a little fuzzy on this part, but I believe they do fetal and maternal blood tests before birth and if the mother is Rh- and fetus Rh+ then RhoGAM is administered prior to birth. Thus, if there is blood transfer during delivery, RhoGAM binds up the Rh-antigens from the fetal blood and the Rh- mother has an immune response.
Unlike IgG, RhoGAM does not cross the placenta so it isn't an issue for the fetus.