A recent paper published by Malan et al in the Journal of the American Medical Association (JAMA) describes a clinical study conducted over two years looking into the potential for reducing risk of miscarriage when performing cell-free fetal DNA (cfDNA) testing, NIPT testing, as compared to invasive fetal testing procedures.
It has been hypothesised that invasive testing procedures could pose a risk to the fetus, increasing the rate of miscarriage, and that by conducting cfDNA screening first, invasive testing could be limited to those testing positive, reducing the overall number of invasive tests performed to at-risk pregnancies potentially reducing the risk for miscarriages induced by the invasive testing procedure. In this study the tests were conducted for pregnancies with a high risk of trisomy 21.
In all, 1997 women completed the study. The study observed that the miscarriage rate for both groups was 0.8%, representing no statistically significant risk reduction for NIPT testing compared to invasive procedures. Although this was the first randomized trial to directly compare NIPT with invasive testing, the results confirm thosepublished earlier by Wulff et al. (2016)(147,987 pregnancies) and Akolekar et al. (2015)(42 716 pregnancies). These studies concluded that invasive procedures present a much lower, or no significant increased risk compared to non-invasive procedures in risk pregnancies.
Wulff, C.B. et al, Risk of fetal loss associated with invasive testing following combined first-trimester screening for Down syndrome:a national cohort of 147 987 singleton pregnancies. Ultrasound Obstet Gynecol 2016; 47: 38–44