The present study showed that late preterm infants needed more PPV in the delivery room compared with other gestational ages. As expected, late preterm neonates required more resuscitation procedures during their transition from the intra- to extra-uterine environment. According to Escobar et al. , greater attention should be given to clinical management, intervention, and follow-up of late preterm newborns, with the need for structured research in this area. The present study analyzed aspects that have not been extensively covered by investigators, such as the need for resuscitation procedures in the delivery room. However, importantly, PPV was not associated with delivery by C-section as shown by logistic regression analysis.
Late preterm and early term are associated with increased morbidity including the need for resuscitation in the delivery room. A cohort study in the United States on elective C-sections showed that more than one third of deliveries were performed before 39 complete weeks of gestation . Additionally, the children born were at a higher risk of mortality and several other adverse neonatal occurrences, including the need for cardio-pulmonary resuscitation in the first 24 h of life .
An interesting finding in our study was that neonates who were born between 37 and 38 weeks of gestational age were not more likely to need PPV compared with those born between 39 and 41 weeks of gestational age. Three recent observational studies, which did not study morbidity in the delivery room, consolidated previous findings of an increased risk of neonatal composite morbidity, respiratory morbidity, and neonatal admission with elective cesarean delivery at 38 weeks of gestation compared with 39 weeks of gestation [11–13]. In contrast, results from the first randomized trial were recently reported in which there was no significant difference in the risk of neonatal admission with elective cesarean delivery between these two gestational weeks . Our results are similar to those of De Almeida et al. . They did not find any differences in the need for PPV provided by mask or endotracheal tube between 37–38 and 39–41 weeks of gestational age. Unfortunately, one of the limitations of this study was not having followed these newborn, so we have no information about the follow-up of these babies.
With regard to use of supplementary oxygen in the delivery room, we observed that 13.1 % of newborns had received supplementary oxygen, not in the resuscitation sequence, but as a first maneuver. This oxygen was probably used inappropriately through a face mask. Since 2010, the use of oxygen in healthy newborns in the delivery room has been considered as not necessary  but this is still performed in delivery rooms in Brazil. The same result was found in a previous analysis using only term newborns without risks .
At all gestational ages, the risks of prolonging pregnancy must be carefully weighed up against the adverse risks of prematurity. The obstetric risk increases the chances of newborns requiring PPV in the delivery room, as found in the present study. However, late preterm birth significantly increases the necessity for PPV. Therefore, considering the morbidity for neonates born between 34 and 37 weeks of gestational age, efforts should be focused on minimizing the unnecessary premature birthrate and improving the outcome of these children [16, 17].
In our study, C-section in labor was associated with the need for PPV and oxygen in the delivery room. However, after adjustments for maternal disorders and gestational age, the type of delivery for these outcomes was no longer significant. This finding is different from a previous study in Brazil, where non-urgent cesarean delivery contributed to an increased need for PPV in the delivery room . However, the population of these studies was different. De Almeida et al.’s study only included newborns at term and studied only non-urgent or elective cesarean. Our study included late preterm and C-sections that were performed during labor.
Throughout the world, the most common causes of neonatal death are preterm birth complications, intrapartum-related complications (birth asphyxia), and neonatal sepsis . In the current study, those births that were late preterm were more likely to be subjected to resuscitation in the delivery room. Therefore, actions that could avoid these circumstances are key to reducing risks. Anticipation, adequate preparation, accurate evaluation, and prompt initiation of support are critical steps for successful neonatal resuscitation. Knowledge about risk factors in the delivery room is essential for avoiding severe birth asphyxia and death as well as helping to plan adequate care.