An Increase of the Cardiothoracic Ratio Leads to a Diagnosis of Bart’s Hydrops
Vorapong Phupong MD,*
Affiliation : * Department of Obstetrics and Gynecology, Faculty of Medicine, Chulalongkorn University
Background : Thalassemia is a common single gene disorder in Southeast Asia. α-thalassemia is a group of
syndrome characterized by deficient production of the α-globin chain. Individuals with heterozygous α-
thalassemia-1 are at risk of having a fetus that has Hemoglobin Bart’s hydrops fetalis (Hb Bart’s). Usually,
when the hemoglobin electrophoresis in heterozygous α-thalassemia-1 is normal, the Mean Corpuscular
Volume (MCV) is lowered. We report a case of increased cardiothoracic ratio that led to a diagnosis of Hb
Bart’s in a couple who had normal hemoglobin electrophoresis and low MCV.
Case Report : A 23-year-old woman, gravida 2, Para 0-0-1-0, initially presented for antenatal care at 13
weeks pregnancy. Her MCV was 67 fentolitre, DiChlorophenol-IndolPhenol (DCIP) test was negative and
hemoglobin electrophoresis was normal. Her husband’s MCV was 67 fentolitre, and hemoglobin electro-
phoresis was normal. Cardiomegaly (an increased of the cardiothoracic ratio) was detected by ultrasonogram
at 25 weeks of gestation. She and her husband were comprehensively counseled after an Hb Bart’s was
suspected. A cordocentesis was performed and the fetal blood was tested for hemoglobin electrophoresis. The
result was later known and confirmed as Hb Bart’s. The couple decided to terminate the pregnancy. The
induced abortion was successful and the patient was discharged on the second day after the abortion. She was
well at the 4-week follow-up.
Conclusion : A prenatal ultrasonographic screening should be conducted in couples who are suspected of
being α-thalassemia-1 carriers when DNA study of α-globin gene cannot be performed. The increase of
cardiothoracic ratio will help detect an early stage of Hb Bart’s.
Keywords : Cardiothoracic ratio, Hemoglobin Bart’s, Hydrops fetalis, Alpha thalassemia
