What's already known about this topic?
- Confined placental mosaicism (CPM) is a known biological phenomenon that can lead to false positive non-invasive prenatal test results.
- The small number of false negative non-invasive prenatal test results reported to date are believed to be because of a low fetal DNA fraction in maternal plasma and/or placental mosaicism
What does this study add?
- The degree and compartmentalization of placental mosaicism can potentially reduce the effective output of fetal DNA into the maternal circulation to steady state levels below the detection limit of non-invasive prenatal testing, leading to a false negative result