Alpha thalassaemia hydrops fetalis in the UK: the importance of screening pregnant women of Chinese, other South East Asian and Mediterranean extraction for alpha thalassaemia trait

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Abstract
Objective Alpha zero (α° or α‐1) thalassaemia is an important genetic risk for women originating from Hong Kong, Singapore, Vietnam, Thailand, the Philippines or South China. Cypriots are also at risk. Carriers of α° thalassaemia trait can be detected by routine haemoglobinopathy screening. When a couple are both carriers, in each pregnancy there is a 25% risk that the fetus will have α thalassaemia hydrops fetalis; this is fatal for the fetus and carries serious obstetric and psychological risks for the mother. Most informed couples at risk request prenatal diagnosis and selective abortion. This study investigates the effectiveness of screening, counselling and prenatal diagnosis for α thalassaemia hydrops fetalis in the UK.Design Retrospective analysis of the notes.Subjects 18 couples attending University College Hospital London for prenatal diagnosis of α thalassaemia hydrops fetalis since 1982.Results The study shows underdiagnosis of both α° thalassaemia trait and α thalassaemia hydrops fetalis leading to avoidable stillbirths and complications in pregnancy.Conclusion We recommend early screening for α° thalassaemia trait for all women of Southeast Asian or eastern Mediterranean origin and the offer of prenatal diagnosis when indicated. The diagnosis of α thalassaemia hydrops fetalis should be considered in women of the relevant ethnic origin who have a stillbirth, neonatal death, abnormal ultrasound findings at fetal anomaly scanning (especially a large placenta), or who develop pre‐eclampsia.