Prenatal diagnosis and management of fetal discordant alpha-thalassaemia in dichorionic diamniotic (DCDA) twins

A 29-year-old nulliparous woman with a dichorionic diamniotic (DCDA) twin pregnancy was referred to our hospital at 16 weeks’ gestation for prenatal diagnosis. She was diagnosed of Haemoglobin H Constant Spring (Hb H CS; --(SEA)/α(CS)α) and her husband of alpha thalassemia-1 trait (--(SEA)/αα). Detailed ultrasound showed that left twin had fetal anaemia and early signs of hydrops while the right one was normal. Both twins were female. Amniocentesis in each sac was performed for prenatal diagnosis of thalassemia after a proper counselling with the couple. DNA analysis confirmed that the left fetus was affected with haemoglobin Bart’s hydrops fetalis (--(SEA)/--(SEA)) while the right one was alpha thalassemia-1 trait (--(SEA)/αα). Selective feticide with intracardiac injection of KCl was successfully performed on the hydropic fetus. Identification of the affected fetus is crucial for selective termination. Family counselling about the procedure and complications is also necessary.