Abstract
Background Screening for fetal chromosomal anomalies using cell-free DNA (cfDNA) became clinically
available in 2012. Since then, it has been widely adopted by providers and pregnant
women with or without risk factors for aneuploidy. Concomitantly, the use of invasive
diagnostic testing has been steadily declining.
Objective To determine the magnitude of decline and changes in indications for invasive prenatal
testing over the past 6 years.
Study Design This was an institutional review board (IRB) approved retrospective cohort study
that included women who were referred to our genetic division for consultation between
January 2010 and December 2015 and decided to have invasive testing. The total number
of patients choosing either option was determined for each year over the entire period
and grouped by following indications: advanced maternal age, abnormal maternal serum
screening (MS), abnormal ultrasound finding (US), personal or family history of genetic
anomaly (FH), and others. Patients, who were advanced maternal age (AMA), were offered
noninvasive prenatal screening or chorionic villus sampling (CVS) or amniocentesis
in addition to routine nuchal translucency screening. The proportion of AMA patients
choosing each of the three options was determined in a 6-month interval over the entire
study period. Statistical analysis included logistic regression and chi-square test.
Results While the number of patients receiving genetic counseling at our unit remained unchanged
over the study period, the number of invasive procedures declined steadily from 429
amniocentesis (amnio) and 154 CVS in 2010 to 72 amnio and 60 CVS in 2015 (p < 0.001). Over the same period, the distribution of indications for diagnostic testing
changed significantly. The proportion of procedures performed due to AMA or MS declined
significantly over time (p < 0.001). The proportion of procedures performed for AMA declined at an average yearly
rate of 24% (95% CI: 19–29%) and those performed for MS declined at a yearly rate
of 13% (95% CI: 6–20%). Over the same period, the proportion of procedures performed
due to US, FH, and other indications combined increased (p < 0.001) at an average rate of 45% (95% CI: 36–55%). A total of 5,188 women (61%
of the study cohort) had genetic counseling for AMA. The percentage of patients opting
for invasive procedures with AMA as the sole indication declined significantly from
38% in 2010 to 2% in 2015 (p < 0.0001) at an average rate of 29% (95% CI: 27–31%) reduction every 6 months. The
rate of AMA women opting for cf DNA increased precipitously from 28% in 2012 to 91%
in 2015 (p < 0.0001) at an average rate of 66% increase (95% CI: 57–76%) every 6 months.
Conclusion The use of invasive procedures to diagnose chromosomal and genetic anomalies has
declined over the past years, primarily due to the availability of cfDNA testing for
AMA and abnormal serum screening. The new reality is that fewer women opt for invasive
procedures and do so primarily following abnormal ultrasound findings or due to a
history of chromosomal or genetic anomalies. Given these trends, it is likely that
future generations of maternal–fetal medicine (MFM) subspecialists will not have the
opportunity to acquire the necessary skills to perform these procedures, when needed.
Keywords
invasive testing - chorionic villus sampling - amniocentesis - cfDNA
