Efficacy and safety of interferon alpha for essential thrombocythemia during pregnancy: two cases and a literature review

For pregnant women with essential thrombocythemia (ET), no standard approach for managing the platelet count has been established. We present the cases of two pregnant women with ET treated with interferon (IFN)-alpha. Each case showed a marked platelet decrease, from values within normal limits at the time of delivery, with no severe adverse events. To clarify the efficacy and safely of IFN alpha for ET during pregnancy, we performed a literature review. A total of 43 pregnant women with ET were ultimately identified from 12 articles and the present cases. IFN-alpha therapy decreased platelet counts to normal levels at birth in many cases, and there were no adverse events that required the discontinuation of IFN-alpha treatment. Overall, 93% of pregnant women with ET gave birth to healthy babies. We consider that, given its efficacy and safety, IFN-alpha therapy is a reasonable treatment option for pregnant women with ET.