What is indicated by "blue babies"?

"Blue babies" refers to newborns who exhibit a bluish discoloration of the skin, particularly around the lips and extremities, due to insufficient oxygen in the arterial blood, a condition known as cyanosis. This condition typically arises from congenital heart defects or other respiratory issues that cause inadequate oxygenation of the blood.

When oxygen levels in the blood are low, hemoglobin takes on a darker, bluish color instead of the bright red associated with oxygen-rich blood, leading to the characteristic cyanosis. This situation can signal serious underlying health issues that may require immediate medical attention.

The other options do not accurately describe the phenomenon of "blue babies." For instance, excess oxygen in the blood would lead to a condition opposite of cyanosis, where individuals would appear normal or even flushed due to oxygen saturation. High blood pressure and low heart rate are unrelated to the oxygen level issues that cause the bluish appearance in these infants.