Noninvasive Prenatal Testing

Abstract

INTRODUCTION: Our objective was to assess the effect of the availability of noninvasive prenatal testing using circulating cell-free fetal DNA on the uptake of routine chorionic villus sampling (CVS) or genetic amniocentesis for advanced maternal age greater than or equal to 35 years. METHODS: Retrospective cohort study of all women who chose noninvasive prenatal testing from May to December 2012 at the University of California San Diego Fetal Care and Genetics Center. Indications for noninvasive prenatal testing were advanced maternal age, high-risk aneuploidy screening, abnormal ultrasound findings, and a family history of aneuploidy. Data were collected by chart review. The numbers of CVS and amniocenteses performed from May to December 2012 were recorded. RESULTS: Two hundred six patients chose noninvasive prenatal testing and 155 (75%) had advanced maternal age. The remaining 51 had abnormal aneuploidy screening, ultrasound findings, or both suggestive of aneuploidy. For 70 women (34%), advanced maternal age alone was the indication for noninvasive prenatal testing. The mean age of this group was 37.7±2.5 years (range 35–44 years). One of the tests done for advanced maternal age alone was positive for trisomy 21, which was confirmed by CVS. The remaining 69 women (98.6%) declined invasive testing. None of these 69 neonates had abnormal karyotypes. CONCLUSIONS: In our practice, women are choosing noninvasive prenatal testing rather than undergoing invasive testing for the sole indication of advanced maternal age. Although detection of aneuploidy with noninvasive prenatal testing is not 100%, patients with reassuring serum aneuploidy screening and normal ultrasound findings appear to favor a small risk of missing a diagnosis of aneuploidy over the risk of procedure-related pregnancy loss.