Improvements in antenatal screening for Down's syndrome.

Area of Science:

• Prenatal diagnostics
• Maternal-fetal medicine
• Genetics

Background:

• Antenatal screening for Down syndrome is crucial for early detection.
• Current screening methods have limitations in detection rates and false-positive rates.
• Novel markers are being investigated to improve screening efficacy.

Purpose of the Study:

• To evaluate the impact of adding ductus venosus pulsatility index (DVPI), fetal nasal bone examination (NBE), and serum placental growth factor (PlGF) to existing antenatal screening tests for Down syndrome.
• To compare the performance of enhanced screening protocols.

Main Methods:

• Statistical analysis of data from multiple sources.
• Monte Carlo simulations were employed to model screening performance.
• Data were analyzed using the maternal age distribution of live births in England and Wales (2006-2008).

Main Results:

• Adding DVPI, NBE, and PlGF to the Combined test reduced the false-positive rate (FPR) from 16.1% to 3.0% at a 95% detection rate (DR).
• For the Integrated test, the same additions decreased the FPR from 4.1% to 0.6% at a 95% DR.
• The Integrated test with DVPI, NBE, and PlGF demonstrated superior performance compared to the Combined test with the same markers.

Conclusions:

• The addition of DVPI, NBE, and PlGF significantly enhances the screening performance of Combined and Integrated tests for Down syndrome.
• These markers can reduce false-positive rates by over 80%.
• The enhanced Integrated test offers superior screening accuracy compared to the enhanced Combined test.