In many cases, women who are diagnosed with lymphoma, leukemia, myeloma, or another hematologic cancer in the early stages of pregnancy should terminate the pregnancy due to the urgent need for chemotherapy and the increased risk for blood clots associated with pregnancy. At later gestational stages, however, treatment during pregnancy is often feasible.
“Chemotherapeutic agents, especially when administered in combination, should be avoided during the first trimester,” cautioned the authors of a report providing updated guidance for the management of cancers of the blood in pregnancy (Lancet. 2012;379:580-587). “If the mother’s condition necessitates immediate therapy, termination of the pregnancy is strongly recommended.”
They added that exposure to chemotherapy in the second and third trimesters is less likely to result in birth defects, although it does increase the risk of intrauterine growth restriction.
According to the authors, hematologic cancer in pregnancy is rare, meaning much of the evidence on how best to proceed is based on case reports or case series rather than large-scale trials. Nevertheless, such cancers pose a substantial risk to mother and fetus. Among pregnant women, Hodgkin lymphoma is the most common blood cancer and the fourth most common cancer overall, affecting 1 in 6,000 expectant mothers. Non-Hodgkin lymphoma, acute leukemia, and other blood cancers also can occur.
With close monitoring, women who are diagnosed during the first trimester of pregnancy with asymptomatic slow-progression Hodgkin lymphoma may be able to continue carrying the baby and delay treatment until the second trimester.
Because the combination of pregnancy, cancer, and chemotherapy heighten the risk of developing blood clots, pregnant women with blood cancer who wish to continue their pregnancy often require thromboprophylaxis with heparin. Such treatment reduces the risks of deep-vein thrombosis and pulmonary embolism in the mother and may also decrease the risks of placental thrombosis, fetal growth restriction, and death.