The Prognosis of Preterm Infants Born at the Threshold of Viability: Fog Over the Gray Zone - Population-Based Studies of Extremely Preterm Infants.

The limit of viability for premature newborns has changed in recent decades, but whether to initiate or withhold active care for periviable infants remains a subject of debate because the chances of survival and the extent of severe neurological impairment can be unclear. In our review, we analyzed large population-based studies of periviable infants from the past 2 decades. We compared survival rates and the incidence of early complications among survivors, including bronchopulmonary dysplasia, intraventricular hemorrhage, periventricular leukomalacia, retinopathy of prematurity, and necrotizing enterocolitis. Moreover, we assessed the perinatal factors that may affect the survival of preterm infants. We analyzed 15 studies reporting data on preterm infants born between 22 and 28 gestational weeks. None of these studies reported survival of an infant born before 22 gestational weeks. Survival rates of infants born at 24 weeks' gestation were above 50% in most studies. The incidence of each complication was also higher among infants born at ≤24 weeks. Of the analyzed perinatal factors, antenatal corticosteroid therapy, birth weight, female sex, cesarean delivery, singleton pregnancy, and birth in a tertiary-level Neonatal Intensive Care Unit were found to be associated with improved survival in some studies. The different methodologies of the studies limited comparison of the results. Further investigations are needed to gain up-to-date information on the limit of viability, and standardized methods in future studies would enable more accurate comparisons of findings.

Survival and early complications of preterm infants with birthweight less than 500 grams during a 10-year period in Hungary.

BACKGROUND: There are limited data available on the survival and early complications of preterm infants with less than 500 g birthweight. To estimate the outcomes for these infants, it is important for caregivers to be aware of perinatal factors that may affect survival. OBJECTIVES: We assessed the mortality and certain early complications of preterm infants born with less than 500 g in Hungary between 2006 and 2015. METHODS: We reviewed data of 486 infants from the database of the Hungarian Central Statistical Office and in parallel of 407 infants from the "NICU database." The study period was divided into two epochs: 2006-2010 and 2011-2015. RESULTS: The survival was 27.1% in the first epoch and 39.1% in the second epoch, and the incidence of early complications was slightly higher in the second epoch. In the surviving group (first and second epoch combined), gestational age (25.1 vs 23.7 weeks), birthweight (458 vs 447 g) antenatal steroid treatment (66.3% vs 52.3%), surfactant therapy (95.1% vs 84.3%), median Apgar scores (6 vs 3 and 8 vs 5 at 1 and 5 minutes, respectively) and proportion of caesarean delivery (89.3% versus 68.5%) were higher than in the non-surviving group (first and second epoch combined). The proportion of multiple births was lower in the surviving group (15.7% vs 33.4%). CONCLUSIONS: Survival of infants with less than 500 g improved between 2006-2010 and 2011-2015 in Hungary. The slightly higher occurrence of early complications might be associated with improving survival.