Question

When is Rh immunoglobulin given to prevent alloimmunization? What amount?

a) During the first trimester, 300 mcg
b) During the second trimester, 300 mcg
c) During the third trimester, 300 mcg
d) Postpartum, 300 mcg

Answer 1

Rh immunoglobulin is given to an Rh-negative mother carrying an Rh-positive fetus between weeks 26-28 of pregnancy and within 72 hours postpartum, with a standard dose of 300 mcg to prevent alloimmunization and decrease the risk of hemolytic disease of the newborn.

Step-by-step explanation:

Rh immunoglobulin is commonly given to prevent alloimmunization during pregnancy in the context of potential Rh incompatibility. For an Rh-negative mother carrying an Rh-positive fetus, the ideal time to administer Rh immunoglobulin is during the third trimester, specifically between weeks 26 and 28 of pregnancy, as well as within 72 hours after birth. The standard dose of Rh immunoglobulin administered is 300 mcg. This prophylactic treatment is critically important because it has decreased the incidence of hemolytic disease of the newborn (HDN) from about 13-14% to around 0.1% since its introduction. Additionally, RhoGAM may be given after any event that might cause fetal blood cells to enter the maternal circulation, such as abdominal trauma or obstetric procedures.