A

Amniocentesis performed between 15 – 20 weeks is the standard invasive test for molecular diagnosis of hemoglobinopathies such as β-thalassemia; it is done in the appropriate gestational window (18 weeks) and carries lower procedure-related risk than later cordocentesis, while chorionic-villus sampling is now too late and NIPT cannot reliably detect thalassemia mutations [Goossens, 1978, PMID 697535; Kor-anantakul, 1998, PMID 10772567].