In the context of confined placental mosaicism, what can prenatal testing reveal?

In the context of confined placental mosaicism, prenatal testing can indeed reveal that it may lead to positive non-invasive prenatal screen (NIPS) results. Confined placental mosaicism refers to a situation where there is a genetic anomaly that is present in the placenta but not necessarily in the fetus. NIPS, which primarily measures cell-free fetal DNA in the maternal circulation, can pick up the abnormal cells from the placenta leading to a positive result. However, this does not always indicate that the fetus has the same genetic abnormality. This scenario highlights the nuanced relationship between the placental genetic makeup and fetal health, underscoring the importance of further diagnostic testing to evaluate the fetus directly.

Understanding the implications of these results is crucial, as positive NIPS results in cases of confined placental mosaicism might prompt additional invasive testing (like amniocentesis or chorionic villus sampling) to ascertain the genetic status of the fetus. This concept highlights the complexities of prenatal genetic testing and interpretation, emphasizing the need for genetic counseling to provide clear guidance to expectant parents.