[Late preterm infants in Spain: Experience of the 34-36 Neonatal Group]

Introduction: Late preterm (LP) infants (34 -36 weeks of gestation) are the largest group of preterm infants and also the least studied so far. In order to improve their care and reduce the impact of their increased morbidity and mortality, it is essential to know the current situation in Spain.

Population and method: Clinical-epidemiological variables of the LP population of 34 participating hospitals were prospectively collected from 1 April 2011 to 31 March 2016, and were then compared with the Minimum Perinatal Data Set for term births in the database.

Results: Of the 9,121 LP studied, 21.7% of 34, 30.8% of 35, and 47.5% of 36 weeks of gestation. The mortality rate was 2.8%. More than one-quarter (27.7%) were multiple pregnancies. Maternal disease were identified in 47.1% and 41.4% were pathological gestation. Just under half (47.9%) were by Caesarean section and 18.8% were of unknown origin or unjustified. No known cause of prematurity was found in 29%, and 3.1% were recognized as unjustified?caesarean?. Just under half (47%) of the LP were breastfed, and 58.6% required admission to neonatology, with 15.2% to Neonatal Intensive Care Unit. Coded diagnoses were recorded in 46.2%, with the most frequent being jaundice, 43.5%, hypoglycaemia, 30%, and respiratory disorders with 28.7%.

Conclusions: The large sample of LP studied helps us to highlight the higher neonatal mortality and morbidity that this population suffers and the unavoidable relationship of its incidence with multiparity, maternal aging, and the still numerous inductions of labour and unjustified elective caesareans.