Final answer:
The correct action for an Rh-negative mother who gave birth to an Rh-positive baby with negative Coombs' tests is to administer Rho(D) immune globulin (RhoGAM) to the mother within 72 hours to prevent the development of anti-Rh antibodies and future cases of HDN.
Step-by-step explanation:
An Rh-negative woman who has just given birth to an Rh-positive baby has a potential risk of becoming sensitized to the Rh antigen, leading to the production of anti-Rh antibodies. These antibodies could cause hemolytic disease of the newborn (HDN) in subsequent pregnancies with Rh-positive babies. As both the direct and indirect Coombs' test results are negative, which indicates that there is no current antibody-mediated attack on the newborn's red blood cells, the recommended action is to administer Rho(D) immune globulin (RhoGAM) to the mother within 72 hours of the birth. This will prevent her immune system from becoming sensitized to Rh-positive red blood cells and protect future pregnancies.
The use of RhoGAM has significantly reduced the incidence of HDN since its introduction in 1968. It works by destroying any fetal Rh-positive red blood cells that may have entered the maternal circulation, thereby preventing the mother's immune system from reacting and creating antibodies. Given the circumstances of this case, the correct action would be to administer Rho(D) immune globulin intramuscularly to the woman within 72 hours of her baby's birth, even if the Coombs' tests are negative.