Okay, let's tackle this question. The patient is a pregnant Rh-negative woman with an Rh-positive father of the baby. The key issue here is hemolytic disease of the newborn (HDN), which occurs when an Rh-negative mother has an Rh-positive baby. The mother's immune system might produce antibodies against the Rh factor, leading to hemolysis in the fetus.

The correct procedure to prevent HDN is administering Rh immunoglobulin (RhIg). This is typically given at 28 weeks of gestation and after delivery if the baby is Rh-positive. RhIg works by preventing the mother's immune system from recognizing and attacking Rh-positive red blood cells, thus preventing sensitization.

Looking at the options, the correct answer would involve RhIg administration. The other options might include incorrect procedures like routine blood transfusions, unnecessary tests, or other interventions that don't address the Rh incompatibility. Each incorrect option should be explained as not preventing sensitization or being inappropriate for the scenario.

The clinical pearl is to remember that RhIg is prophylactic and must be given before sensitization occurs, usually during pregnancy and postpartum. Missing this timing can lead to future pregnancies being at risk.

**Core Concept**
Hemolytic disease of the newborn (HDN) occurs when an Rh-negative mother is sensitized to Rh-positive fetal red blood cells. Rh immunoglobulin (RhIg) prevents maternal immune response by neutralizing fetal RBCs before antibody formation.

**Why the Correct Answer is Right**
Administering RhIg at 28 weeks gestation and within 72 hours postpartum (if the baby is Rh-positive) blocks sensitization. It binds to Rh-positive fetal RBCs in maternal circulation, preventing macrophage presentation to T-cells and B-cell antibody production. This interrupts the immune cascade that leads to anti-D antibody formation.

**Why Each Wrong Option is Incorrect**
**Option A:** Routine antenatal testing (e.g., ultrasounds) does not prevent sensitization.
**Option B:** Blood transfusion to the mother is not indicated and risks enhancing immune response.
**Option C:** Corticosteroids reduce inflammation but do not prevent Rh sensitization.
**Option D:** Cesarean delivery does not alter Rh incompatibility risk.

**Clinical Pearl / High-Yield Fact**
RhIg must be given **before** sensitization occurs—ideally during pregnancy and postpartum. Once anti-D antibodies are present, RhIg is ineffective. Mnemonic: "28 and 72" for timing of doses.

**Correct Answer: D. Administer Rh immunoglobulin (RhIg) at 28 weeks and after delivery**

✓ Correct Answer: B. Administration of anti-Rh antibodies to the mother postdelivery