The right answer is to look for cyanosis by determining the color of the baby's chest and abdomen,
Cyanosis refers to the bluish coloration that the skin and mucous membranes take when the blood contains a small amount of oxygen-bound hemoglobin.
When there is little oxygen in the blood, it takes on a dark red color. And when all the vessels (of the whole body or a region of the body) carry low oxygenated blood, then it gives the skin the bluish color characteristic of cyanosis.
Symptoms may be associated with that of cyanosis, depending on what causes it. For example, breathing difficulties, chest pain, fever, heart failure or general fatigue.