Association of combined first-trimester screen and noninvasive prenatal testing on diagnostic procedures.

Abstract

To describe the changes over a 9-year period in the number and rate of diagnostic testing after the introduction of the combined first-trimester screen and subsequent noninvasive prenatal testing. The number of prenatal screening and diagnostic tests was recorded over a 9-year period from billing records. Three time intervals were considered: 1) 20 months before a combined first-trimester screen was offered; 2) 72 months after a combined first-trimester screen was offered; and 3) 16 months after noninvasive prenatal testing introduction. Prenatal testing was compared per year, per time interval, and per 100 morphologic ultrasonograms to account for fluctuations in patient number. A total of 15,418 prenatal tests was recorded during the study period, consisting of 9,780 combined first-trimester screen, 1,265 noninvasive prenatal testing, 608 chorionic villus sampling (CVS), and 3,765 amniocenteses. Combined first-trimester screen peaked at 1,836 in 2009-2010 but declined by 48.1% after noninvasive prenatal testing was introduced. Combined first-trimester screen per 100 morphologic ultrasonograms also significantly decreased (P<.05) after noninvasive prenatal testing introduction. Chorionic villus sampling peaked after combined first-trimester screen introduction in 2007-2008 with 100 procedures, representing an 81.8% increase from prefirst-trimester screen. After the introduction of noninvasive prenatal testing, CVS declined by 68.6% during 2012-2013. Chorionic villus sampling per 100 morphologic ultrasonograms followed the same trend. Amniocentesis declined every year of the study period (78.8% overall), including 60.3% after combined first-trimester screen and a further 46.7% after noninvasive prenatal testing. Monthly amniocentesis procedures per 100 morphologic ultrasonograms significantly decreased (P<.05) after introduction of a combined first-trimester screen and noninvasive prenatal testing. The introduction of combined first-trimester screen was associated with an increase in CVS and a decrease in amniocentesis testing. Noninvasive prenatal testing was associated with a subsequent decrease in CVS and further decrease in amniocentesis. LEVEL OF EVIEDENCE: III.