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Aim: We evaluated the increased centralisation of extremely preterm (EPT) births in Sweden in relation to the changes in mortality and morbidity.

Methods: Population-based data covering Swedish live births from 22 + 0 to 26 + 6 weeks of gestation during 2004–2007 and 2014–2016 were analysed for associations between time-period, birth within (inborn) or outside (outborn) regional centres, and outcomes.

Results: Among 1626 liveborn infants, 703 were born in 2004–2007 and 923 in 2014–2016. Birth outside (vs. within) regional centres was associated with a higher infant mortality even after adjustment for birth cohort, gestational age, birthweight standard deviation score and infant sex (adjusted odds ratio 2.01, 95% confidence interval 1.31–3.07, p = 0.001). The higher 1-year mortality in outborn infants was mainly due to more deaths within 24 h after birth. Outborn infants had a higher incidence of intraventricular haemorrhage grade 3–4 than inborn infants (22% vs. 14% in 2004–2007, and 22% vs. 13% in 2014–2016, both p < 0.05). While survival to 1 year without major morbidity increased in inborn infants (33%–40%, p = 0.008), it remained unchanged in outborn infants (29% vs. 30%, p = 0.88).

Conclusion: Centralisation of EPT births contributed to a lower 1-year mortality in 2014–2016 than that in 2004–2007, attributed to a decrease in deaths before 24 h among inborn infants.

OBJECTIVE: To investigate potential risk factors behind the increased incidence of necrotising enterocolitis (NEC) in Swedish extremely preterm infants.

DESIGN: Registry data from two population-based national cohorts were studied. NEC diagnoses (Bell stage ≥II) were validated against hospital records.

PATIENTS: All liveborn infants <27 weeks of gestation 2004-2007 (n=704) and 2014-2016 (n=895) in Sweden.

MAIN OUTCOME MEASURES: NEC incidence.

RESULTS: The validation process resulted in a 28% reduction of NEC cases but still confirmed a higher NEC incidence in the later epoch compared with the earlier (73/895 (8.2%) vs 27/704 (3.8%), p=0.001), while the composite of NEC or death was lower (244/895 (27.3%) vs 229/704 (32.5%), p=0.022). In a multivariable Cox regression model, censored for mortality, there was no significant difference in early NEC (0-7 days of life) between epochs (HR=0.9 (95% CI 0.5 to 1.9), p=0.9), but being born in the later epoch remained an independent risk factor for late NEC (>7 days) (HR=2.7 (95% CI 1.5 to 5.0), p=0.001). In propensity score analysis, a significant epoch difference in NEC incidence (12% vs 2.8%, p<0.001) was observed only in the tertile of infants at highest risk of NEC, where the 28-day mortality was lower in the later epoch (35% vs 50%, p=0.001). More NEC cases were diagnosed with intramural gas in the later epoch (33/73 (45.2%) vs 6/26 (23.1%), p=0.047).

CONCLUSIONS: The increase in NEC incidence between epochs was limited to cases occurring after 7 days of life and was partly explained by increased survival in the most extremely preterm infants. Misclassification of NEC is common.

Objective: To explore associations between perinatal activity and survival in infants born at 22 and 23 weeks of gestation in Sweden.

Design/Setting: Data 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 outcome: One-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.

Results: 977 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).

Conclusion: Increased perinatal activity was associated with reduced mortality and increased chances of survival without MNM in infants born at 22 and 23 weeks of GA.

Objective: To evaluate if postnatal treatment with betamethasone in extremely preterm infants was associated with neurodevelopmental impairment (NDI) at 6.5 years of age.

Design: Prospective cohort study.

Setting: Extremely Preterm Infants in Sweden Study (gestational age <27 weeks, born 2004-2007). Patients: 428 children born extremely preterm were assessed at 6.5 years of age, 115 treated with betamethasone and 313 not treated.

Main outcome measures: NDI at 6.5 years of age. Evaluation at 6.5 years included cognitive testing with the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV), neurological examination and a medical record review.

Exposure: Treatment with postnatal betamethasone. Main outcome: Moderate to severe NDI at 6.5 years of age, defined as a composite including cerebral palsy, and/or impairment in cognition, hearing and vision.

Results: Moderate to severe NDI was more prevalent in children treated with postnatal betamethasone (49% treated vs 26% not treated, p<0.001). Betamethasone-treated children had worse cognitive development with mean WISC-IV score of 75 (SD 13.7) vs 87 (SD 14.0, p<0.001). The effect was dose dependent: 1.35 mg/kg vs 1.0 mg/kg (p=0.01) in betamethasone-treated children with moderate to severe versus no or mild NDI, respectively. The differences remained after adjustment for potential confounders with logistic regression (adjusted OR (aOR) 1.80, 95% CI 1.14 to 3.21). The difference in NDI also remained after propensity score matching, with crude OR 2.82 (95% CI 1.42 to 5.61, p=0.003) and aOR 2.17 (95% CI 1.07 to 4.69, p=0.04).

Conclusion: Postnatal treatment with betamethasone is associated with increased risk of NDI at 6.5 years.

Aim: To study whether a specific cognitive profile can be identified for children born extremely preterm (EPT) by investigating: 1) strengths and weaknesses not revealed by Full-Scale IQ, 2) overlap between different cognitive deficits and 3) proportion of EPT children with multiple deficits.

Methods: We analysed data from the 4th version of Wechsler Intelligence Scales for Children in EPT children (n = 359) and matched controls (n = 367), collected within the 6.5-year follow-up of a population-based prospective cohort study.

Results: Extremely preterm children performed worse than controls on all measures. Group differences were the largest in Perceptual Reasoning (PRI) and Working Memory (WMI), but differences between indices were small. However, when conducting categorical analyses, deficits in PRI and/or WMI were not more common than other combinations. Many EPT children had no or mild cognitive deficits, although often in multiple domains.

Conclusion: Extremely preterm children had greater weaknesses in working memory and perceptual abilities. However, detailed analyses of cognitive subscales showed large heterogeneity and provided no support for a specific cognitive profile. In conclusion, Full-Scale IQ scores hide strengths and weaknesses and individual profiles for EPT children need to be considered in order to provide appropriate support.

Background: At term-equivalent age, infants born prematurely are shorter, lighter and have more adipose tissue compared to term counterparts. Little is known on whether the differences in body composition persist in later age. 

Methods: We prospectively recruited 33 preterm infants (<32 weeks gestational age, mean gestational age 28.1 weeks) and 69 term controls. Anthropometry and body composition (air displacement plethysmography) were monitored up to 4 months of age. Nutrient intakes from preterm infants were collected from clinical records. 

Results: At 4 months of age preterm infants were lighter and shorter than term controls (mean weight-for-age z-score: –0.73 vs. 0.06, p = 0.001; mean length-for-age z-score: –1.31 vs. 0.29, p < 0.0001). The significantly greater percentage of total body fat seen in preterm infants at term-equivalent age (20.2 vs. 11.7%, p < 0.0001) was no longer observed at 4 months. A deficit of fat-free mass persisted until 4 months of age (fat-free mass at term-equivalent age: 2.71 vs. 3.18 kg, p < 0.0001; at 4 months: 4.3 vs. 4.78 kg, p < 0.0001). The fat mass index and fat-free mass index (taking length into account) did not differ between the groups. Nutrition had little effect on body composition. Higher protein intake at week 2 was a negative predictor of fat-free mass at discharge. 

Conclusions: At 4 months corrected age, preterm infants were both lighter and shorter than term controls and the absolute fat-free mass deficit remained until this age. Little effect of nutrition on body composition was observed.

Aim: Few studies have examined the parents of moderately preterm children. The aim of this study was to investigate the experiences of parents of both extremely and moderately preterm children. 

Methods: Qualitative telephone interviews were conducted in 2013-2014 with 13 mothers and 10 fathers of extremely preterm children and with 11 mothers and seven fathers of moderately preterm children. The children were born between 2000 and 2003. Data were analysed with a narrative approach. 

Results: Parents of extremely preterm children recounted dramatic birth stories that, for most, ended positively. Parents of moderately preterm children presented more neutral birth stories, and most recounted that their children did not receive attention for prematurity from medical staff. Parents from both groups described staff mem-bers’ treatment in terms of long-lasting impressions, and they were deeply affected by the hospital environment and the other parents and children admitted. Parents whose children died or were disabled recounted dramatic stories and endless fights for support. 

Conclusion: Parents from both groups reported long-lasting impressions of the medi-cal staff and the hospital environment, which they found important to talk about, even a decade after the birth of their child/children.

This study aimed to investigate cognitive and behavioral outcomes in relation to gestational age (GA) in school-aged children born preterm (PT). Results from the Wechsler Intelligence Scale for Children, 4th edition (WISC-IV), and the Child Behavior Checklist (CBCL) were analyzed in 51 children (mean age: 7.8 years [range: 7.0–8.7]) born PT (mean GA: 31 weeks [range: 23–35]; birth weight, mean: 1,637 g [range:404–2,962]) with the majority (96%) having no diagnosed cognitive, sensory, or motor impairments. The control group included 57 age-matched typically developing children (mean age: 7.9 years [range: 6.2–8.7]) born full-term (FT). Children born PT, extremelyPT (GA < 28) in particular, showed significantly lower cognitive performance and higher behavioral problem scores compared with children born FT. GA was found to predict aspects of both cognitive functioning and behavioral problems within the PT group, with lower GA being related to both poorer cognitive outcomes and elevated affective and attention-deficit/hyperactivity problems. Global cognitive functioning did not independently predict aspects of behavioral outcomes. Findings demonstrate that, even in children born PT without severe perinatal and/or postnatal complications and receiving active perinatal care, a short gestation is an evident risk factor for long-term negative effects on mental health independent of cognitive functioning. Additional findings suggest that both reduced growth and lower parental educational level may contribute to increased risk for poorer cognitive and behavioral functioning in children born PT.

IMPORTANCE: Since 2004-2007, national guidelines and recommendations have been developed for the management of extremely preterm births in Sweden. If and how more uniform management has affected infant survival is unknown.

OBJECTIV: To compare survival of extremely preterm infants born during 2004-2007 with survival of infants born during 2014-2016.

DESIGN, SETTING AND PARTICIPANTS: All births at 22-26weeks' gestational age (n = 2205) between April 1, 2004, and March 31, 2007, and between January 1, 2014, and December 31, 2016, in Sweden were studied. Prospective data collection was used during 2004-2007. Data were obtained from the Swedish pregnancy, medical birth, and neonatal quality registries during 2014-2016. EXPOSURES Delivery at 22-26 weeks' gestational age.

MAIN OUTCOMES AND MEASURES: The primary outcomewas infant survival to the age of 1 year. The secondary outcome was 1-year survival among live-born infants who did not have any major neonatal morbidity (specifically, without intraventricular hemorrhage grade 3-4, cystic periventricular leukomalacia, necrotizing enterocolitis, retinopathy of prematurity stage 3-5, or severe bronchopulmonary dysplasia).

RESULTS: During 2004-2007, 1009 births (3.3/1000 of all births) occurred at 22-26 weeks' gestational age compared with 1196 births (3.4/1000 of all births) during 2014-2016 (P =.61). One-year survival among live-born infants at 22-26 weeks' gestational age was significantly lower during 2004-2007 (497 of 705 infants [70%]) than during 2014-2016 (711 of 923 infants [77%]) (difference, -7%[95% CI, -11% to -2.2%], P =.003). One-year survival among live-born infants at 22-26 weeks' gestational age and without any major neonatal morbidity was significantly lower during 2004-2007 (226 of 705 infants [32%]) than during 2014-2016 (355 of 923 infants [38%]) (difference, -6%[95% CI, -11% to -1.7%], P =.008).

CONCLUSIONS AND RELEVANCE: Among live births at 22-26 weeks' gestational age in Sweden, 1-year survival improved between 2004-2007 and 2014-2016.