Use of the Combined First-Trimester Screen in High- and Low-Risk Patient Populations After Introduction of Noninvasive Prenatal Testing.

OBJECTIVES: To report changes in the use of the combined first-trimester screen (FTS) in patients classified as high and low risk for fetal aneuploidy, including after introduction of noninvasive prenatal testing (NIPT). METHODS: A prospectively collected database was reviewed to investigate changes in FTS use before and after American College of Obstetricians and Gynecologists (ACOG) Practice Bulletin No. 77 (Obstet Gynecol 2007; 109:217-227), which recommended that all patients be offered aneuploidy screening, and after NIPT introduction. High-risk patients were classified as 35 years or older at the estimated time of delivery or those with an abnormal prior screen, abnormal ultrasound findings, or family history of aneuploidy. Data were normalized per 100 morphologic ultrasound examinations to account for changes in patient number over time. Statistical significance was defined as P < .05. RESULTS: A total of 10,125 FTSs were recorded during the 88-month study period, including 2962 in high-risk patients and 7163 in low-risk patients. The total number of FTSs performed per 100 morphologic ultrasound examinations significantly increased after ACOG Practice Bulletin No. 77 and significantly decreased after NIPT introduction. In high-risk patients, the total number of FTSs performed per 100 morphologic ultrasound examinations significantly increased after ACOG Practice Bulletin No. 77 but significantly decreased after NIPT introduction. In contrast, in low-risk patients, the total number of FTSs performed per 100 morphologic ultrasound examinations significantly increased after ACOG Practice Bulletin No.77 but was not statistically different after NIPT introduction. CONCLUSIONS: American College of Obstetricians and Gynecologists Practice Bulletin No. 77 significantly increased patient use of FTS. The introduction of NIPT significantly decreased FTS use in the high-risk population but not in the low-risk population.

Uptake of noninvasive prenatal testing at a large academic referral center.

OBJECTIVE: Noninvasive prenatal testing (NIPT) is a recently developed risk-assessment technique with high sensitivity and specificity for fetal aneuploidy. The effect NIPT has had on traditional screening and diagnostic testing has not been clearly demonstrated. In this study, NIPT uptake and subsequent changes in the utilization of first-trimester screen (FTS), chorionic villus sampling (CVS), and amniocentesis in a single referral center is reported. STUDY DESIGN: Monthly numbers of NIPT (in high-risk patients), FTS, CVS, and amniocentesis were compared between a 35-month baseline period (April 2009 through February 2012) before introduction of NIPT, and the initial 16 months following NIPT introduction divided in 4-month quarters beginning in March 2012 through June 2013. RESULTS: A total of 1265 NIPT, 6637 FTS, 251 CVS, and 1134 amniocentesis were recorded over the 51-month study period in singleton pregnancies of women who desired prenatal screening and diagnostic testing. NIPT became the predominant FTS method by the second quarter following its introduction, increasing by 55.0% over the course of the study period. Total first-trimester risk assessments (NIPT+FTS) were not statistically different following NIPT (P = .312), but average monthly FTS procedures significantly decreased following NIPT introduction, decreasing by 48.7% over the course of the study period. Average monthly CVS and amniocentesis procedures significantly decreased following NIPT introduction, representing a 77.2% and 52.5% decrease in testing, respectively. Screening and testing per 100 morphological ultrasounds followed a similar trend. CONCLUSION: NIPT was quickly adopted by our high-risk patient population, and significantly decreased alternate prenatal screening and diagnostic testing in a short period of time.

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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.