There are two foetal diagnostic approaches available:

1. The conventional approach: This method involves obstetric procedures to obtain foetal DNA or blood for molecular and/or Hb analysis. It is invasive and carries a slightly higher risk of procedure-related foetal loss or complications, although the rates of complications are generally low. The primary advantage of this approach is that it provides a definitive diagnosis early in pregnancy, allowing for earlier management and reducing parental anxiety.
2. The non-invasive approach or ultrasound algorithm: The second approach involves a serial ultrasound algorithm. Its main advantage is the reduced need for invasive procedures. However, this method requires continuous follow-up of the pregnant woman, which may result in increased parental anxiety. Ultrasound algorithm can avoid invasive diagnostic procedures in approximately 70% of cases and can detect nearly all affected cases during the pre-hydropic phase [24].