20 May 2019 The neonatal period is the phase between birth and 28th day. During this period, the baby undergoes very rapid, important changes to adapt to life outside the womb. Although these babies already have important skills, they are especially fragile and dependent on adults. Part of the newborn’s fragility is that the signs and symptoms of illness are not always clear, which makes it difficult to handle them. Sometimes the general impression the baby conveys to us is enough to distinguish serious situations from those that are not of concern, but this is not always the case. In newborns it is therefore especially important watch for the following warning signs : Persistent groaning; Persistent, inconsolable crying; Apnoea: pause in breathing for more than 20 seconds with bluish skin (cyanosis); Breathing difficulty: noisy breathing, stridor, wheezing, flared nostrils, inter / infracostal retraction, cyanosis; Fever: under-arm temperature higher than 37.5 - 38º C; Hypothermia: under-arm temperature below 36ºC; Colour changes: marked pallor, marbled skin, cyanosis, rash; Difficulty in suckling / weak sucking / vomiting; Severe floppiness / persistent drowsiness that interferes with feeding; Foul smell or redness around the umbilicus; Diarrhoea (watery, abundant, and numerous evacuations different from those from breast milk); No evacuation for more than 3 days; Pain when moving; Seizures: may be the first sign of a neurological dysfunction. In the neonatal period, seizures may be very different: staring or deviation of the eyes that does not react to stimulation, apnoea, jerking of the arms and legs that does not stop with restraint, repetitive blinking, persistent, repetitive chewing movements, convulsive tonic / clonic movements; Feeling that the baby is different from his or her comfort state causing the parents concern. This article was written with the support of physicians and other clinical professionals from the Hospital da Luz network. The content published in the Health Guide is intended for the general public and is provided for informational and educational purposes only. It does not replace individual medical assessment, diagnosis, or personalized clinical advice from a qualified healthcare professional. The content is produced or reviewed by physicians and other healthcare professionals at Hospital da Luz and is based on the knowledge available at the time of publication or the most recent update, as indicated at the beginning of each item.