Impact of Labor on Outcomes in Transient Tachypnea of the Newborn: Population-Based Study

Abstract

Transient tachypnea of the newborn (TTN) is the most common cause of neonatal respiratory distress; its estimated incidence is 1 % to 2%. Although a number of risk factors for TTN have been identified, the main risk factors include elective cesarean section (ECS), lower gestational age, male gender, and low birth weight. Previous studies have shown a positive impact of labor on respiratory outcomes among infants with TTN, but the impact of labor on the severity of TTN has not been investigated. This population-based cohort study investigated the effect of labor on the risk and course of TTN in a large, representative sample of term singleton neonates in Germany. Between 2001 and 2005, perinatal databases in the federal states of Hesse and Saarland were used to identify cases of TTN among singletons born at a gestational age ≥37 weeks, and to examine neonatal outcomes in all infants admitted to a neonatal center. Data for the TTN group was compared with national perinatal data for term singletons (control group) born during the study period. The International Classification of Diseases, 10th Revision was used to diagnosis TTN. Of the 239,971 term births included in the final analysis, 13,346 (5.6%) were transferred to a neonatal ward and 1423 (0.59%) cases of TTN were diagnosed. This represented an overall TTN incidence of 5.9 cases per 1000 singleton live births. Risk factors for TTN included ECS, low gestational age, male gender, and low birth weight. There was a significant association between the absence of labor before birth and longer duration of oxygen supplementation (P < 0.02), and an increased risk of TTN and severity of TTN at term. Prolonged labor reduced the need for oxygen supplementation and conversely, a decrease in labor duration increased the need (P < 0.028). These findings show that ECS and the absence of labor at term are strong risk factors for the development of TTN. Absence of labor or reduced labor duration is associated with increased severity of TTN and the need for oxygen supplementation.