How successful is rhogam for ABO incompatibility?

Not used for it. The ABO and rhesis blood grouping systems are separate issues altogether. Rhogam is used to prevent an rh- mother from becoming sensitized to a rh+ baby & developing antibodies that would destroy some of the babies blood for that or future pregnancies. The Rhogam has no effect on potential ABO issues.
It is not. Rhogam was developed to prevent rh sensitization in pregnancies where the mother is rh- and the fetus is rh+. Rhogam has no role in managing ABO incompatibility, which is due to an entirely different group of red blood cell antigens.

Related Questions

Mom is type o+ and dad is ab+: is this ABO incompatibility and is there a need for rogam coz she had a miscarriage for her first and 2nd preg. Wat would be the probable cause?

Miscarriage &Rhogam. Rhogam is used only in rh negative mothers. This mother is +. A baby she carried would be a or b, and she could have high anti-a and/or anti-b antibody levels. If she did, that would be ABO incompatibility. It's not usually so severe. after 2 losses, she needs a high risk pregnancy specialist. Read more...
Unlikely the issue. Rhogam is unnecessary & only for Rh issues, not ABO. ABO "set ups" are rarely if ever a problem, causing at most minor treatable jaundice. Repeated fetal loss can be from as diverse issues as an incompetent cervix or a parent with a balance chromosomal anomaly. A consult with a perinatologist and a geneticist may be your best source of information. It would help if there was info on both losses. Read more...