152 Obstetrics and Gynecology Board Review •••
❍ What are the different types of alpha thalassemia?
Alpha thalassemia trait: Deletion of one alpha globin gene, which is usually asymptomatic
Alpha thalassemia minor: Deletion of two alpha globin genes, either on the same or opposite chromosomes. This
causes mild to moderate microcytic anemia.
Hemoglobin H disease: Deletion of three of four alpha globin genes, leading to a mixture of hemoglobin Bart (γ4),
hemoglobin H (β4), and hemoglobin A. Patients have moderate to severe hemolytic anemia
Alpha thalassemia major: Deletion of all four alpha globin chains, which are incompatible with extrauterine life.
❍ What is beta thalassemia?
Impaired production of beta globin chains, causing precipitation of alpha globin in red blood cells.
❍ What are characteristics of beta thalassemia major (Cooley anemia)?
The infant born with beta thalassemia major is healthy at birth but as hemoglobin F levels fall it develops anemia
and failure to thrive.
❍ Elevated hemoglobin F (>2%) and A2 (>3.5%) are associated with which condition?
Beta thalassemia minor.
❍ How is von Willebrand disease inherited?
Most variants are inherited in an autosomal dominant fashion.
❍ What is Virchow triad?
Conditions that lead to an increased risk of venous thrombosis are (1) stasis, (2) vessel trauma, and (3)
hypercoagulability.
❍ Which clotting factors rise in pregnancy?
Factors I, VII, VIII, X, von Willebrand factor, and plasminogen activator inhibitors 1 and 2, which are all
procoagulants.
❍ Which clotting factors diminish during pregnancy?
Protein S, an anticoagulant.
❍ What is the most common inherited thrombophilia?
Heterozygous factor V Leiden mutation.
❍ Who should be screened for thrombophilia?
Women with a personal or family history of venous thromboembolic disease. Women with unexplained fetal loss at
20 weeks, severe preeclampsia or HELLP prior to 34 weeks, or with severe growth restriction had previously been
screened for thrombophilia; however, this is no longer recommended because there is a lack of data showing that
anticoagulation reduced recurrence.
❍ Screening for inherited thrombophilias should include which conditions?
Factor V Leiden, prothrombin G20210A mutation, as well as antithrombin III, protein C and protein S
deficiencies, as well as antiphospholipid antibodies.