Introduction to a How I Treat series on hematologic complications in pregnancy

The hematologic complications of pregnancy encompass congenital and acquired disorders that may affect both the mother and the fetus. Interventional studies are rarely performed in pregnant women, who are largely excluded from clinical trials, so evaluation and treatment of these disorders need to be extrapolated from treatment of nonpregnant patients. In this How I Treat series, clinical experts discuss their approach to a sampling of the following hematologic challenges in pregnant women:

• Kieron Dunleavy and Claire McLintock, “How I treat lymphoma in pregnancy”

• Barbara Ferrari and Flora Peyvandi, “How I treat thrombotic thrombocytopenic purpura in pregnancy”

• Saskia Middeldorp and Wessel Ganzevoort, “How I treat venous thromboembolism in pregnancy”

• Frank W. G. Leebeek, Johannes Duvekot, and Marieke J. H. A. Kruip, “How I manage pregnancy in carriers of hemophilia and patients with von Willebrand disease”

In the first paper, Dunleavy and McLintock discuss the approach to diagnosing and treating lymphoma in pregnancy, a rare occurrence, but one that is usually associated with aggressive disease. Diagnostic modalities are chosen with an eye toward protecting the fetus, with different considerations based on the stage of the pregnancy. Treatment is similarly tailored to protect the fetus but must be adequate to treat the underlying lymphoma without endangering the long-term survival of the mother. They outline the complex decision process with careful counseling of the parents in determining the optimal approach.

The second paper, by Ferrari and Peyvandi, focuses on thrombotic thrombocytopenic purpura (TTP), a disease that can be congenital or acquired. Patients with congenital TTP often experience their first episode in association with pregnancy or may have increased manifestations during pregnancy; alternatively, patients may develop acquired TTP during pregnancy or have it recur in pregnancy. The authors discuss the challenges of managing this disorder in pregnancy and counseling for future pregnancies.

Unlike lymphoma and TTP, which are relatively rare disorders, venous thromboembolism (VTE) is a common disorder in all populations. It is seen in 0.1% to 0.2% of all pregnancies and is an important cause of morbidity and mortality for the mother. Middeldorp and Ganzevoort discuss the diagnosis and treatment of VTE during pregnancy with emphasis on safety issues regarding diagnostic procedures, choice of anticoagulation, and management of delivery

The first 3 papers in this series deal with the development, usually unexpected, of hematologic issues that intrude into pregnancy. The final paper deals with the management of patients with 2 known bleeding disorders, hemophilia carrier status and von Willebrand disease, in the setting of pregnancy. In this case, the potential risk to the mother and fetus can be anticipated, allowing for counseling and intervention to minimize risks. Despite this, the approach to delivery and postpartum care remains complex and somewhat controversial.

All of these conditions endanger the life of both the pregnant mother and her fetus, but data to support optimal management remain limited. We hope that this collection presenting data-informed expert opinions by leaders in the field will prove useful in practice.