Utility of ultrasound examination at 10-14 weeks prior to cell-free DNA screening for fetal aneuploidy.

OBJECTIVE

To estimate the frequency of unexpected first-trimester ultrasound findings that would alter prenatal management in pregnant women eligible for cell-free (cf) DNA screening because of advanced maternal age (AMA).

METHODS

This was a retrospective cohort study of all AMA women at a tertiary care center who had a 10-14-week ultrasound examination between 1 January 2012 and 27 April 2015. Information on pregnancy dating, obstetric ultrasound examination, prenatal screening and genetic testing were collected from a perinatal database. The primary outcome was an unexpected ultrasound finding in the first trimester that would alter the prenatal screening/testing strategy.

RESULTS

In total, 2337 women met the inclusion criteria, with a total of 2462 fetuses. Sixty-eight (2.9%) women had an anomalous fetus, of which 44 (64.7%) had diagnostic testing. In the entire cohort, a non-viable pregnancy was identified in 153 (6.5%) women. Multiple gestation was identified in 32 (1.4%) women; five had a cotwin demise. Gestational dating was revised for 126 (5.4%) women. Among those who opted for aneuploidy screening (n = 1806), 68.5% had cfDNA screening and 31.5% had first-trimester screening by analysis of maternal serum biomarkers and nuchal translucency thickness. Among those eligible for cfDNA screening, 16.1% (95% CI, 15.0-18.0%; 377/2337) had an ultrasound finding (anomaly, incorrect dating, multiple gestation, non-viable pregnancy) at the time of testing that would have altered the provider's counseling regarding the prenatal screening/testing strategy.

CONCLUSIONS

A substantial proportion of AMA women eligible for cfDNA screening have fetal ultrasound findings that could alter genetic testing strategy and clinical management. This study recommends ultrasound examination prior to cfDNA screening in AMA women. Copyright © 2016 ISUOG. Published by John Wiley & Sons Ltd.