First trimester Down syndrome screening: public health implications

Down syndrome (DS) screening has been an integral part of routine prenatal screening for the last three decades. Recent efforts have been directed at developing additional non-invasive prenatal screening techniques that could not only improve sensitivity of prenatal screening, but also be employed in the first trimester to offer earlier diagnostic and interventional opportunities. Nuchal translucency has proven to be an effective and cost-effective screening test that, when combined with serum markers (hCG and pregnancy-associated plasma protein [PAPP-A]) in the first and/or second trimester, broadens the diagnostic possibilities and improves the diagnostic capabilities of current prenatal DS screening methods. Despite the potential benefits, significant operational issues regarding access to and availability of such testing may limit its widespread application and necessitates the maintenance of both non-sonographic and second trimester screening methods. The implementation of first trimester DS testing requires the development and maintenance of nationally standardized quality control systems to ensure the reliability of serum and ultrasound measurements and the accurate assessment of risk. Future efforts to improve prenatal screening should continue to emphasize the need for improved access to all aspects of prenatal care, stress the importance of provider education and the necessity for extensive patient counseling, and reinforce the role of patient education and choice.