Final answer:
The appropriate treatment for a fetus affected by isoimmunization is intrauterine transfusion. Isoimmunization occurs due to Rh factor incompatibility, leading to erythroblastosis fetalis or HDN, and RhoGAM is given to prevent this immune response.
Step-by-step explanation:
The correct treatment for a fetus affected by isoimmunization is a. Intrauterine transfusion. This condition typically occurs in cases of Rh factor incompatibility, where an Rh-negative mother's immune system creates antibodies against her Rh-positive fetus's red blood cells. This can lead to hemolytic disease of the newborn (HDN), also known as erythroblastosis fetalis. Isoimmunization is often managed by giving the pregnant person RhoGAM during and possibly after the first pregnancy to prevent the immune response against future Rh-positive babies. If the fetus develops anemia due to the mother's antibodies, an intrauterine transfusion may be necessary to treat the fetus.
Maternal blood transfusion or plasmapheresis is not typically used as a treatment for the fetus in isoimmunization cases. Induction of labor may be considered if the fetus is at a gestational age where it can survive outside of the womb and the risks of continuing the pregnancy are too high. Preventive measures include administering Rho(D) immune globulin during and after pregnancies with Rh+ fetuses to prevent sensitization and subsequent production of maternal anti-Rh antibodies.