Risk assessment of survival and morbidity of infants born at <24 completed weeks of gestation

Abstract

Background: Infants born at the threshold of viability have a high risk of mortality and morbidity. The British Association of Perinatal Medicine (BAPM) provided updated guidance in 2019 advising a risk-based approach to balancing decisions about active versus redirected care at birth.

Aims: To determine survival and morbidity of infants born between 22 and 24 completed weeks of gestation. To develop a scoring system to categorise infants at birth according to risk for mortality or severe adverse outcome.

Methods: A retrospective, single centre observational study of infants who received neonatal care from 2011 to 2021. Data were collected on mortality, morbidity and two-year neurodevelopmental outcomes. Each infant was risk categorised utilising the proposed tools in the BAPM (2019) framework. A composite adverse score for either dying or surviving with severe impairment was created.

Results: Four infants born at 22 weeks, 49 at 23 weeks and 105 at 24 weeks of gestation were included. The mortality rate was 23.4 %. Following risk categorisation there were 8 (5.1 %) extremely high risk, 44 (27.8 %) high risk and 106 (67.1 %) moderate risk infants. The rate of dying or surviving with severe impairment for extremely high risk, high risk and moderate risk were 100 %, 88.9 % and 53 % respectively. The proportions with the composite adverse outcome differed significantly according to the risk category (p < 0.001).

Conclusions: When applying a scoring system to risk categorise infants at birth, high rates of dying or surviving with severe impairment were found in infants born at 22 or 23 weeks of gestation.

Keywords: Mortality; Neurodevelopmental impairment; Prematurity; Viability.