One-year survival and outcomes of infants born at 22 and 23 weeks of gestation in Sweden 2004–2007, 2014–2016 and 2017–2019

Abstract

ObjectiveTo explore associations between perinatal activity and survival in infants born at 22 and 23 weeks of gestation in Sweden.Design/SettingData on all births at 22 and 23 weeks’ gestational age (GA) were prospectively collected in 2004–2007 (T1) or obtained from national registers in 2014–2016 (T2) and 2017–2019 (T3). Infants were assigned perinatal activity scores based on 3 key obstetric and 4 neonatal interventions.Main outcomeOne-year survival and survival without major neonatal morbidities (MNM): intraventricular haemorrhage grade 3–4, cystic periventricular leucomalacia, surgical necrotising enterocolitis, retinopathy of prematurity stage 3–5 or severe bronchopulmonary dysplasia. The association of GA-specific perinatal activity score and 1-year survival was also determined.Results977 infants (567 live births and 410 stillbirths) were included: 323 born in T1, 347 in T2 and 307 in T3. Among live-born infants, survival at 22 weeks was 5/49 (10%) in T1 and rose significantly to 29/74 (39%) in T2 and 31/80 (39%) in T3. Survival was not significantly different between epochs at 23 weeks (53%, 61% and 67%). Among survivors, the proportions without MNM in T1, T2 and T3 were 20%, 17% and 19% for 22 weeks and 17%, 25% and 25% for 23 weeks’ infants (p>0.05 for all comparisons). Each 5-point increment in GA-specific perinatal activity score increased the odds for survival in first 12 hours of life (adjusted OR (aOR) 1.4; 95% CI 1.3 to 1.6) in addition to 1-year survival (aOR 1.2; 95% CI 1.1 to 1.3), and among live-born infants it was associated with increased survival without MNM (aOR 1.3; 95% CI 1.1 to 1.4).ConclusionIncreased perinatal activity was associated with reduced mortality and increased chances of survival without MNM in infants born at 22 and 23 weeks of GA.