Rho-gam

[kronickm]

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Could someone explain to me how rho-gam prevents allo-immunization of a mother against her nait's Rh. Or how IvIG works on say Pla-1 antibody. (Or provide me with a decent link)




(Some of you have transfusion med xperience right?)

 

[LADoc00]

no.

seriously, you write all that but are too lazy to type it into wikipedia and read it??

BTW, its spelled G-O-O-G-L-E

 

[kronickm]

maybe I should have been more specific.

So basically the rhogam binds the fetal antibodies that cross the placenta before they can activate B-cells. I understand that Rh disease of the newborn is caused by maternal IgG that crosses the placenta.

Why is it that the rhogam IgG does not cross the placenta?

Is the rhogam IgG such that it will not destroy fetal RBCs in vitro?

 

[mlw03]

rho-gam is usually given immediately after deliver of an Rh+ baby to an Rh- mother, or anytime an Rh- mother bleeds during pregnancy unless they are SURE the baby's father is also Rh-. that's a good question about whether the rho-gam could cross the placenta. my thought: yes, it probably does, but a little bit of fetal hemolysis can be tolerated in exchange for preventing the mother's sensitization to the Rh antigen, thus making future pregnacy very difficult.

 

[djmd]

It might be that Rho-gam and others are made up of IgG2 which does not cross the placenta... Or that the amount that does is not enough to produce significant hemolysis...

and they generally give a prophylactic dose of it at about 28 weeks regardless of any bleeding (or if the father is known Rh-).... Well they don't have to even if the father is negative, but I think most guidlines just don't mention it...

Better safe than sorry...