How does Rhogam prevent erythroblastosis fetalis?

Answer 1

If an Rh-negative woman gives birth to an Rh-positive baby, she is given an injection of Rhogam within 72 hours of the birth. This immunoglobulin destroys any fetal blood cells in her bloodstream before her immune system can react to them. In cases where this precaution is not taken, antibodies are created, and future pregnancies may be complicated. Because antibody production does not usually begin in a previously unsensitized mother until after delivery, erythroblastosis in subsequent children can be prevented by giving the mother an injection of Rhogam within 72 hours of delivery. The preparation must be given after each pregnancy-whether it ends in delivery,The anti-Rh antibodies from the preparation destroy fetal RBCs in the mother's blood before they can sensitize the maternal immune system. If a massive fetomaternal hemorrhagehas occurred, additional injections of the preparation may be necessary. This treatment has a failure rate of about 1-2 percent, apparently due to the mother's sensitization during pregnancy rather than at delivery. Therefore, all mothers who have Rh-negative blood and no apparent sensitization (as indicated by antibody titer) should be treated with a standard 300g dose of Rh(D) immune globulin (Rhogam) at about 28 weeks of gestation. The exogenous antibodies in the mother's circulation are gradually destroyed over the next three to six months, and the mother remains unsensitized. Rhogam should also be given after any episode of bleeding and after delivery should be as nontraumatic as possible. The placenta should not be removed manually to avoid squeezing fetal cells into the maternal circulation. A newborn born with erythroblastosis should be attended to immediately by a pediatricianwho is prepared to perform an exchange-transfusionat once if required.

By NITIN BAYAL

M.Sc. Molecular Biology & Biotechnology

TEZPUR CENTRAL UNIVERSITY, ASSAm