Prenatal Screening and Diagnosis: Time for a Paradigm Shift.

Area of Science:

• Prenatal screening and diagnosis
• Genetics and imaging in obstetrics

Background:

• Established prenatal screening practices relied heavily on Down syndrome detection and maternal age.
• Advances in genetic testing and imaging necessitate a reevaluation of current prenatal screening protocols.

Purpose of the Study:

• To advocate for a paradigm shift in prenatal screening and diagnosis.
• To integrate recent advancements in genetic and imaging technologies into clinical practice.

Main Methods:

• Review of current practices in prenatal screening and diagnosis.
• Emphasis on noninvasive prenatal testing (NIPT) with cell-free DNA.
• Recommendation for increased utilization of chromosomal microarray analysis (CMA).

Main Results:

• Noninvasive prenatal testing with cell-free DNA achieves over 99% detection for Down syndrome.
• CMA can identify chromosomal aberrations missed by karyotyping, even in low-risk pregnancies.
• Sonographic 'soft markers' lack significance with normal cell-free DNA screening results.

Conclusions:

• Noninvasive prenatal testing with cell-free DNA should be the first-line screening for Down syndrome for all pregnant individuals.
• Chromosomal microarray analysis should be routinely offered with invasive testing.
• Age alone (e.g., >35 years) should no longer define high-risk pregnancies for chromosomal abnormalities if screening is negative.