**2. Neonatal care and the main problems in newborns**

The risk of death is greater on the first day of life and it has been confirmed that the proportion of deaths occurring during the first week of life are constant in all regions and economic environments. This highlights the urgent need to provide timely and high-quality care from the moment of birth. The time between a potentially harmful event and death can be very short and the first minute after birth (golden minute) is the crucial window for neonatal resuscitation.

In general, all newborns are vulnerable after childbirth, which is a key point for growth and development. The highest risk of death is concentrated immediately after birth and in the first days of life. For most newborns, essential care is required, which the mother will ideally provide, such as providing warmth, a clean and safe environment, and providing nourishment through breastfeeding. However, in premature or low birth weight babies, the care requirements are greater since these children are especially vulnerable to thermal instability, difficulty breathing, feeding limitations, and the risk of infections.

In particular, premature babies are especially vulnerable and can become hypothermic in a matter of minutes, which increases the risk of respiratory distress, hypoglycemia, infections, and death. Problems related to childbirth and premature delivery are predominant causes of early neonatal mortality, while infections are more common in the late neonatal period [9].

Due to the abovementioned, temperature is an aspect of basic care for newborns. This is considered fundamental because hypothermia increases the probability of early and late neonatal death [10–12]. Consequently, by providing appropriate thermal conditions during delivery, immediate care, and in intensive care rooms, the risk of hypothermia is reduced and neonatal survival is improved. In this sense, differences have been observed in admission temperatures between extreme and moderate preterm infants, and it has been confirmed that extreme premature infants have more frequently low and high temperatures at admission. In addition, an inverse relationship between temperature at admission and intrahospital mortality has been observed [13].

Other frequent problem in preterm and very low birth weight infants is hypoglycemia as a consequence of their limited reserves of glycogen and fat, and the inability to use alternative substrates for energy production. In these babies, recurrent and prolonged episodes of hypoglycemia are associated with severe brain damage and poor neurodevelopmental outcome [14–16]. The incidence of neonatal hypoglycemia has been reported between 5 and 15% in healthy children, although it exceeds 50% in risk neonates, while severe hypoglycemia reaches 20% of these children [17].

However, as previously noted, neonatal hypoglycemia not only affects high-risk infants but also continues to be a cause of significant morbidity in term and near-term newborns [18], so this problem should be a priority within preventive actions and early treatment in neonatal care.

In knowledge of the conditions and risk factors of newborns, differential detection and control measures have been proposed. For example, in term neonates, control has been proposed for 12 h after childbirth, while in smaller children the evaluation is continued for 48 h. In other conditions, such as the diabetic mother's son, 24-h monitoring has been recommended [17, 19].

Lately and considering the potential deleterious effects of hypoglycemia, measures of continuous monitoring of glycemia have been proposed, which has shown good tolerance in the newborns and absence of complications. This can detect episodes of neonatal hypoglycemia and hyperglycemia that would not otherwise be detected with intermittent measurements [20]. The use of continuous glucose monitoring in newborns can reduce the frequency of blood sampling and improve glycemic stability, with more time in the euglycemic range. It has also shown a better and timelier detection of episodes of hypoglycemia compared with conventional methods such as intermittent capillary glucose testing [21].

Respiratory disorders are also frequent problems in newborns. Respiratory distress syndrome (RDS) is the most common cause of respiratory distress in preterm infants and the most of children born extremely prematurely evolve rapidly with RDS after birth. The incidence is higher while the baby's gestational age is lower. Up to 98% of babies born at 23 weeks and 86% of babies born at 28 weeks develop RDS [22]. However, the incidence of RDS has decreased in recent decades as a consequence of the use of continuous positive airway pressure (CPAP), conventional ventilation, high-frequency ventilation, and replacement of surfactant for newborns [23].
