What is the target hemoglobin (Hb) level for a pregnant patient with non-transfusion dependent thalassemia (NTDT) and pulmonary hypertension?

Hemoglobin Target for NTDT in Pregnancy with Pulmonary Hypertension

Maintain hemoglobin at approximately 10 g/dL throughout pregnancy in patients with non-transfusion-dependent thalassemia (NTDT) and pulmonary hypertension, using intensified transfusion support to achieve this target. 1

Rationale for Hemoglobin Target

The hemoglobin target of 10 g/dL is specifically recommended for pregnant women with thalassemia major and applies equally to NTDT patients, particularly when complicated by pulmonary hypertension. 1 This target ensures:

• Optimal fetal growth by increasing blood consumption during pregnancy 1
• Reduced cardiac strain in the setting of pulmonary hypertension, where maternal mortality risk is extremely high (17-33% in recent studies) 2
• Prevention of hypoxemia-related complications that contribute to morbidity beyond iron overload alone 3

Critical Management Considerations for Pulmonary Hypertension

Pulmonary hypertension in pregnancy carries exceptionally high maternal mortality risk (17-33%), with deaths occurring primarily in the last trimester and early postpartum period due to pulmonary hypertensive crises, thrombosis, or right heart failure. 2 This risk exists even in patients with minimal disability before pregnancy. 2

Mandatory Pre-Pregnancy Assessment

• Cardiac T2 MRI* is mandatory before conception to identify iron-related cardiac damage and assess left ventricular function 1
• Patients with cardiac T2* <6 ms have approximately 14% risk of arrhythmia within one year 1
• Women with severe cardiac iron overload face substantially higher maternal risk and require specialized planning 1

Transfusion Strategy

Intensified transfusion support is required to maintain the 10 g/dL target throughout pregnancy. 1 For NTDT patients who have never been transfused or received minimal transfusions:

• High risk of severe alloimmune anemia exists if transfusions become necessary during pregnancy 4
• Early initiation of transfusion support prevents this complication 4
• Regular transfusions reduce ineffective erythropoiesis and hemolysis that contribute to cardiac strain 3, 5

Thromboprophylaxis Requirements

Prophylaxis with heparin or low-molecular-weight heparin is mandatory, particularly given the combination of:

• Pregnancy increasing thrombosis risk three-fold to four-fold 4
• Thalassemia representing a hypercoagulable state 4
• Pulmonary hypertension further elevating thrombotic risk 1
• Splenectomized patients having significantly elevated thrombotic risk 1, 4

Prophylaxis should continue throughout pregnancy and the postpartum period. 4

Cardiac Monitoring Protocol

Close cardiac surveillance is critical throughout pregnancy as increased blood volume and blood pressure changes may compromise heart function in the setting of pulmonary hypertension. 1 Cardiac complications occur in 1.1% to 15.6% of pregnancies in women with thalassemia. 1

Iron Chelation Considerations

• Stop all chelators at conception, particularly deferiprone and deferasirox due to teratogenic concerns 1
• In patients with severe cardiac iron overload (relevant given pulmonary hypertension), deferoxamine can be restarted toward the end of the second trimester, balancing maternal cardiac risk against potential fetal effects 1, 4

Delivery Planning

Delivery must occur at expert centers with multidisciplinary teams experienced in both high-risk obstetrics and thalassemia management. 1 The combination of NTDT and pulmonary hypertension represents an extremely high-risk scenario requiring:

• Cardiologist involvement throughout pregnancy 1
• Avoidance of general anesthesia (a risk factor for maternal death in pulmonary hypertension) 2
• Vaginal delivery with epidural analgesia preferred when possible 2

Critical Pitfalls to Avoid

• Allowing hemoglobin to fall below 10 g/dL, which compromises fetal growth and increases maternal cardiac strain 1
• Omitting thromboprophylaxis in this hypercoagulable state 1, 4
• Managing outside expert centers with multidisciplinary teams 1
• Failing to perform preconception cardiac assessment with T2* MRI 1
• Delaying transfusion support in previously non-transfused NTDT patients, risking alloimmune anemia 4