Testing, testing: Prenatal genetic screening

The June 2016 issue of Obstetrics and Gynecology includes a study of the conversations between patients and “Health Care Providers” about prenatal genetic screening (PGS). The objective of the study was to “assess how obstetric health care providers counsel patients regarding prenatal genetic screening and how these conversations influence patients’ screening decisions.” PGS refers to blood and ultrasound tests performed early in pregnancy to determine whether a fetus is at high risk for various chromosomal anomalies, especially the anomaly that leads to Down syndrome. Several findings of the study are troubling.

First troubling finding: providers’ counseling of patients about PGS lasts an average of 1.5 minutes.

Second troubling finding: False-positive rates of PGS are discussed so rarely that they could not be reliably analyzed in the study. The false-positive rate refers to how often the screening test is wrong when it suggests that an abnormality is present; when a test says the baby has Down syndrome, but the baby in fact does not have Down syndrome, it is a false-positive. The guidelines of the American College of Obstetricians and Gynecologists...