Final answer:
Rh incompatibility prevention is the priority for Rh-negative mothers, but since the question depicts an Rh-positive mother, it's not a concern. The prioritized outcome for this mother should be postpartum depression screening and monitoring the infant's weight gain and growth.
Step-by-step explanation:
Given that the mother is rubella-immune and with Rh-positive blood, the most crucial outcome for this client is c) Rh incompatibility prevention. This is because if the mother is exposed to Rh-positive fetal red blood cells, her immune system could produce anti-Rh antibodies. These antibodies could cross the placenta in future pregnancies and result in hemolytic disease of the newborn (HDN), leading to severe conditions such as anemia, brain damage, or even fetal death. However, because the mother is already Rh-positive, it means she would not form anti-Rh antibodies against her own Rh-positive baby, eliminating this as an immediate concern. Therefore, the remaining critical outcomes would be d) Postpartum depression screening which is important for all new mothers given the risk of postpartum mood disorders, and ensuring good health and progression for the mother and baby post-delivery, which includes a) Infant's weight gain and growth.