Severe forms of thalassaemia include β-thalassaemia major, β-thalassaemia/haemoglobin E disease and Hb Bart’s hydrops foetalis. The option of termination of pregnancy may be offered to couples who have a foetus affected by one of these conditions. Before conceiving, PGT is also an option for these couples in order to avoid this dilemma.

Genetic counselling is important, and a complete thalassaemia screening is necessary in both partners to identify the risk of having a baby with HbH disease or haemoglobin Bart’s hydrops foetalis (see Chapter 14).

The majority of individuals with HbH disease (i.e., deletional HbH disease) have a mild course, thus termination of pregnancy is usually not indicated in affected cases. As such, prenatal diagnosis programmes are not generally offered to identify pregnancies at risk for deletional forms of HbH disease, especially considering the risk and benefit of the procedure. Furthermore, while PGT is not harmful to pregnancy, it is costly. Various possible complications can still occur; such as ovarian hyperstimulation, and complications associated with ovum pick up [42, 43]. Not many cases of PGT for deletional HbH have been reported. However, non-deletional HbH disease is typically more severe and can cause moderate to severe anaemia with more frequent need for blood transfusions. PGT may be an option for couples at risk of having a child with non-deletional HbH disease.

Once the genotype of couples or the affected pregnancy is identified, counselling of the clinical course and the risk and benefit of prenatal diagnosis, or PGT, should be discussed. Some couples might opt to go ahead with the procedure to select an unaffected embryo or choose to end the pregnancy.