Second-trimester maternal serum screening for fetal Down syndrome: As a screening test for hemoglobin Bart's disease: A prospective population-based study.

Second-trimester maternal serum AFP levels were significantly elevated in cases of fetal Hb Bart's disease. Pregnancies with unexplained elevated serum AFP levels in areas of high prevalence of Hb Bart's disease should always undergo a detailed ultrasound examination to detect any early signs of fetal anemia before development of hydrops fetalis.