Which characteristic might lead a nurse to suspect a newborn has Down syndrome?

A protruding tongue is a common physical characteristic associated with Down syndrome, which arises from an extra chromosome 21 (trisomy 21). Newborns with Down syndrome often exhibit a range of distinctive features, and a protruding tongue is particularly notable due to the hypotonia (decreased muscle tone) that many affected infants experience. This hypotonia can lead to a smaller oral cavity and difficulties in controlling the tongue, making it more likely to protrude.

Additionally, other features often observed in infants with Down syndrome may include a flat facial profile, slanted eyes, and a single transverse palmar crease, but the protruding tongue is one of the more immediate and visually striking indicators that can prompt further assessment for this condition. In contrast, the other characteristics mentioned, such as a smooth forehead, even spacing of fingers, and large amounts of hair, do not specifically correlate with Down syndrome and can be found in a variety of normal newborns, making them less relevant for suspicion of the condition.