In pregnancy, hemolysis can be markedly accelerated. Rituximab, along with prednisone, is first-line treatment (Luzzatto, 2015). Coincidental thrombocytopenia usually corrects with therapy. Transfusion of red cells is complicated by antierythrocyte antibodies, but warming the donor cells to body temperature may decrease their destruction by cold agglutinins.
These hemolytic anemias must be diferentiated from other causes of autoimmune hemolysis. In most cases, hemolysis is mild, it resolves with drug withdrawal, and recurrence is prevented by avoidance of the drug. One mechanism is hemolysis induced through drug-mediated immunological injury to red cells. he drug may act as a high-ainity hapten when bound to a red-cell protein to which antidrug antibodies attach-for example, IgM anti penicillin or anticephalosporin antibodies. Some other drugs act as low-ainity hap tens and adhere to cell membrane proteins. Examples include probenecid, quinidine, rifampin, and thiopental. A more common mechanism for drug-induced hemolysis is related to a congenital erythrocyte enzymatic defect. An example is glucose-6-phosphate dehydrogenase deiciency, which is common in African-American women and discussed later (p. 1080).
Drug-induced hemolysis is usually chronic and mild to moderate, but occasionally acute hemolysis is severe. Garratty and coworkers (1999) described seven women with severe Coombs-positive hemolysis stimulated by cefotetan given as prophylaxis for obstetrical procedures. Alpha-methyldopa can cause similar hemolysis (Grigoriadis, 2013). Moreover, maternal hemolysis has been reported after intravenous immune globulin therapy (Rink, 2013). Withdrawal of the ofending drug frequently halts the hemolysis.
Unexplained severe hemolytic anemia can develop during early pregnancy, and it resolves within months postpartum. A clear immune mechanism or red cell defects are not contributory (Starksen, 1983). Because the fetus-neonate also may demonstrate transient hemolysis, an immunological cause is suspected. Maternal corticosteroid treatment is often-bur not alwaysefective (Kumar, 2001). We have cared for a woman who during each pregnancy developed intense severe hemolysis with anemia that was controlled by prednisone. Her fetuses were not afected, and in all instances, hemolysis abated spontaneously after delivery.
In some cases, hemolysis is induced by conditions unique to pregnancy. Mild microangiopathic hemolysis with thrombocytopenia is relatively common with severe preeclampsia and eclampsia (Cunningham, 2015; Kenny, 2015). This HELLP (hemoysis) devated fiver enzyme levels) Low .latelet count} syndrome is discussed in Chapter 40 (p. 719). Another is acure fatty liver of pregnancy, which is associated with moderate to severe hemolytic anemia (Nelson, 2013). It is discussed in Chapter 55 (p. 1060).