What is the most common complication of β‑thalassemia major in pregnancy?

Common Complications of Thalassemia Major in Pregnancy

The most common complications of β-thalassemia major in pregnancy are cardiac complications (occurring in 1.1-15.6% of cases), followed by spontaneous miscarriage/fetal loss (9-33.3%), and obstetric complications including gestational diabetes, preeclampsia, and hypertension. 1

Cardiac Complications

Cardiac complications represent the primary maternal risk and occur in 1.1% to 15.6% of pregnancies in women with thalassemia major. 1 The mechanism involves:

• Iron overload-related cardiac dysfunction that is exacerbated during pregnancy due to increased blood volume, changes in blood pressure, and interruption of chelation therapy due to teratogenic concerns 1
• Increased blood consumption during pregnancy (to maintain hemoglobin around 10 g/dL) combined with cessation of chelation significantly worsens iron overload 1
• Pre-existing cardiac iron burden is the critical determinant—cardiac T2* assessment and functional evaluation before conception are essential 1

Key Management Points:

• Cardiac T2 and function must be assessed before conception* to identify women at highest risk 1
• Cardiac function requires careful monitoring throughout pregnancy due to the hemodynamic stress of increased blood volume 1
• Restarting iron chelation with deferoxamine toward the end of the second trimester should be considered in patients with severe heart or liver iron overload 1

Pregnancy Loss and Fetal Complications

Spontaneous miscarriage and fetal loss occur in 9% to 33.3% of pregnancies in women with thalassemia major. 1 Additional fetal/obstetric risks include:

• Preterm births occur at increased rates due to underlying maternal or obstetric complications 1
• Twin or triplet pregnancies are common (19% in one cohort) because most women require induction of ovulation due to hypogonadism-related impaired fertility 2

Obstetric Complications

Obstetric complications including gestational diabetes, preeclampsia, and hypertension are reported frequently in thalassemia major pregnancies. 1

• Cesarean delivery rates range from 24% to 100% due to fetopelvic disproportion, osteoporosis, maternal HIV infection, or patient choice 1
• Thromboembolism prophylaxis with heparin or low-molecular-weight heparin is indicated, particularly in splenectomized patients 1

Iron Overload Progression

Iron accumulation increases significantly during pregnancy, especially in the liver. 2 In one cohort:

• Median ferritin levels increased from 1071 ng/ml before pregnancy to 2231 ng/ml after pregnancy (p < 0.0001) 2
• Mean liver iron concentration increased from 3.37 mg/g dry weight to 9.06 mg/g dry weight (p = 0.0001) after pregnancy 2
• Prompt resumption of chelation after delivery is mandatory to prevent long-term organ damage 2

Critical Pitfalls to Avoid

• Do not delay cardiac assessment—women with preexisting cardiac disease or large amounts of cardiac iron have substantially increased maternal risk 1
• Do not manage these pregnancies in non-expert centers—such pregnancies require a multidisciplinary team at expert centers due to increased risk to mother and baby 1
• Do not forget thromboprophylaxis—particularly critical in splenectomized patients 1
• Do not delay resumption of chelation postpartum—iron accumulation during pregnancy necessitates aggressive chelation after delivery 2