Impact of introducing cell-free DNA screening into clinical care on first trimester ultrasound

OBJECTIVE

First-trimester ultrasound is an important component of prenatal care. We investigated the impact of introducing cell-free DNA (cfDNA) aneuploidy screening into routine care, on performance of first-trimester ultrasound.

METHODS

Retrospective study of patients who had prenatal care at a tertiary referral center. We compared the performance of any first-trimester ultrasound between three different aneuploidy screening protocols, used consecutively during the study period: (1) combined first-trimester screening (FTS); (2) FTS and cfDNA offered together; (3) patients requested to choose between FTS and cfDNA. Secondary outcomes included performance of nuchal translucency (NT), aneuploidy screens and diagnostic genetic procedures.

RESULTS

The number of patients undergoing first-trimester ultrasound remained similar with the second protocol but decreased in the third (68.7% vs. 40.9%, OR 0.32, 95% CI 0.25-0.4, p < 0.001). Diagnostic procedures decreased between protocol 1 and 2 (7.6% vs. 4.4%, OR 0.59, 95% CI 0.37-0.93, p = 0.02) while NT scans decreased between protocol 2 and 3 (6.8% vs. 1.3%, OR 0.18, 95% CI 0.09-0.4, p < 0.001). The rate of FTS decreased over the study period and less women had cfDNA when they had to choose one method (p < 0.001).

CONCLUSIONS

Introducing cfDNA screening as an alternative to FTS, resulted in fewer patients receiving ultrasound in the first-trimester.

Patient attitudes toward prenatal diagnostic testing during antenatal care in an urban population

OBJECTIVE

Investigate factors that influence the decision to accept or decline diagnostic testing for pregnant women referred for genetic counseling.

METHODS

Cross sectional anonymous survey of pregnant women undergoing genetic counseling at a tertiary care referral center. Subjects' perceived risk of procedure related loss and fetal chromosomal problem were obtained via survey where patients rated risk from 0 (no risk) to 10 (highest risk).

RESULTS

There were no differences in sociodemographic factors between women undergoing a diagnostic procedure compared to those not undergoing a procedure. As the perceived risk for having a baby with genetic problem increased by one point, the estimated odds of having the diagnostic procedure increased by 43% controlling for the perceived risk of procedure related loss (p < .0001). Similarly, as the perceived risk of miscarriage increased by one point, the odds of having the diagnostic procedure decreased by 40%, controlling for the perceived risk of having a baby with a genetic problem (p < .0001). The main reason women cited for not undergoing a procedure was fear of procedure related loss.

CONCLUSIONS

Pregnant women that decline diagnostic testing have a higher perceived risk of procedure related loss and lower perceived risk of fetal chromosomal abnormality than those who accept.