Abstract
Background The rhesus factor D (RhD)-negative patients who give birth to an RhD-positive newborn
or who are otherwise exposed to RhD-positive red blood cells are at risk of developing
anti-D antibodies. These antibodies may cause hemolytic disease of the fetus and newborn
(HDFN). During pregnancy, prevention of alloimmunization is completed with a Rho(D)
immune globulin (RhIg).
Cases We report two cases, where obese patients developed alloimmunization, with high neonatal
titers, after appropriate RhIG prophylaxis during the index pregnancy.
Conclusion Our cases demonstrate cases of anti D-alloimmunization in an index pregnancy, with
high neonatal titers. Both patients are obese, with BMI > 35 mg/m2.
Key Points
-
RhIG can be administered via intramuscular or intravenous formulations. Overall, it
appears that both formulations are equally effective. The optimal administration,
especially with obese women, is not clearly established.
-
Our cases demonstrate that obesity is a risk factor for failure of RhIG, and could
lead to an increase in HDFN.
Keywords
alloimmunization - Rh negative - hemolytic disease of the fetus and newborn - anti-D
antibodies - Rhophylac - RhIG
