Newborn nails cover the root of the purple may be caused by environmental factors, may also be pathological reasons, such as heart disease. 1. environmental factors: newborns thermoregulation center is not well developed, adults in the environment of the temperature of the newborns may not be able to adapt, when feeling the cold, the blood vessels will be contracted, resulting in poor peripheral circulation, blood flow is reduced, thus causing the newborns fingernails cover the root of the purple, cold hands and feet phenomenon. 2. Heart disease: congenital heart disease can lead to problems with blood supply to the heart, which in turn leads to poor blood supply to the extremities and lack of oxygen, resulting in purple fingernails in newborns. There may be other reasons for purple fingernails in newborns, and after eliminating physiological factors, it is recommended to consult a doctor in time to identify the cause and then targeted treatment.