When should anti-D immunoglobulin be administered to pregnant women?

The administration of anti-D immunoglobulin, also known as Rho(D) immune globulin, is most commonly recommended at 28 weeks of gestation or following any fetal trauma. This is crucial for Rh-negative women who are carrying an Rh-positive fetus, as exposure to Rh-positive blood can lead to sensitization and subsequent complications in future pregnancies. By administering the immunoglobulin around this time, it helps to prevent the development of antibodies against Rh-positive red blood cells, thereby protecting both the mother and future pregnancies.

In addition to the 28-week administration, it's also important to provide the immunoglobulin immediately following any situation that might lead to fetal blood cell exposure, such as trauma or invasive procedures. This timing is based on clinical guidelines that have demonstrated the efficacy of this preventive measure in reducing the risk of hemolytic disease of the newborn in Rh-negative women.

The other options do not align with current clinical guidelines. Administration at the end of the first trimester or immediately after conception would not adequately address the timing needed to prevent sensitization. Waiting until after delivery might expose the mother to the risks associated with sensitization without prior prevention. Thus, the recommended practice of administering anti-D immunoglobulin in the 28th week of gestation