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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.

Aim: Children born extremely preterm frequently have developmental coordination disorder (DCD). We aimed to evaluate perinatal risk factors for DCD.

Methods: Swedish national cohort study including 226 children born before 27 gestational weeks without major neurodevelopmental disabilities at 6.5 years. Outcome was DCD, defined as ≤5th percentile on the Movement Assessment Battery for Children-Second Edition. Perinatal risk factors were evaluated using multivariable logistic regression.

Results: DCD was present in 84/226 (37.2%) children. Of the risk factors known at 40 weeks gestation, independent and significant risk factors for DCD were: mother's age at delivery (odds ratio [OR] 1.73, 95% confidence interval [CI] 1.07–2.80); pre-eclampsia (2.79, 1.14–6.80); mother born in a non-Nordic country (2.23, 1.00–4.99); gestational age per week increase (0.70, 0.50–0.99) and retinopathy of prematurity (2.48, 1.26–4.87). Of factors known at discharge, postnatal steroids exposure (2.24, 1.13–4.46) and mechanical ventilation (1.76, 1.06–2.09) were independent risk factors when added to the model in separate analyses.

Conclusion: The risk of DCD in children born extremely preterm was multifactorial and associated with gestational age largely mediated by ROP, maternal factors, pre-eclampsia, administration of postnatal steroids and mechanical ventilation. These risk factors are common among children born extremely preterm, contributing to their high risk of DCD.

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.

Aim: To investigate the ability of the Bayley Scales of Infant and Toddler Development -Third Edition (Bayley-III), scores to predict later Wechsler Intelligence Scale for Children - Fourth Edition (WISC-IV), performances in a cohort of children born extremely preterm.

Methods: 323 children, born <27 gestational weeks, were tested with the Bayley-III at corrected age 2.5 years and with the WISC-IV at 6.5 years. Regression analyses investigated the association between Bayley-III scores and WISC-IV full-scale intelligence quotient (IQ). The ability of Bayley-III Cognitive Index scores to predict low IQ was evaluated using receiver operating characteristic curves.

Results: Bayley-III Cognitive Index scores and IQ had a moderately positive correlation and accounted for 38% of the IQ variance. Using a Bayley-III cut-off score of 70, the sensitivity to detect children with IQ<70 was 18%, and false positive rate was 7%. A Bayley-III cut-off score of 85 corresponded to sensitivity and false positive rates of 44% and 7%, respectively.

Conclusions: Results emphasise the relative importance of Bayley-III Cognitive Index scores as predictors of IQ. An 85 score cut-off for suspecting subnormal IQ is supported. A less conservative threshold would increase identification of true cases yet increase the risk of wrongly diagnosing children.

The study aim was to explore the relationship between a developmental assessment at preschool age and an intelligence quotient (IQ) assessment at school age. One hundred sixty-two children were assessed at 2.5 years with the Bayley Scales of Infant and Toddler Development-Third Edition (Bayley-III) and then at 6.5 years with the Wechsler Intelligence Scale for Children-Fourth Edition (WISC-IV). The Bayley-III Cognitive Index score was the Bayley entity that showed the highest correlation with WISC-IV Full-Scale IQ (FSIQ; r = .41). There was a significant difference between the individual WISC-IV FSIQ and the Bayley-III Cognitive Index scores. Analyses showed an average difference of -4 units and 95% limits of agreement of -18.5 to 26.4 units. A multivariate model identified the Bayley-III Cognitive Index score as the most important predictor for FSIQ and General Ability Index (GAI), respectively, in comparison with demographic factors. The model explained 24% of the total FSIQ variation and 26% of the GAI variation. It was concluded that the Bayley-III measurement was an insufficient predictor of later IQ.

BACKGROUND AND OBJECTIVES: The risk of cerebral palsy (CP) is high in preterm infants and is often accompanied by additional neurodevelopmental comorbidities. The present study describes lifetime prevalence of CP in a population-based prospective cohort of children born extremely preterm, including the type and severity of CP and other comorbidities (ie, developmental delay and/or cognitive impairment, neurobehavioral morbidity, epilepsy, vision and hearing impairments), and overall severity of disability. In this study, we also evaluate whether age at assessment, overall severity of disability, and available sources of information influence outcome results.

METHODS: All Swedish children born before 27 weeks’ gestation from 2004 to 2007 were included (the Extremely Preterm Infants in Sweden Study). The combination of neonatal information, information from clinical examinations and neuropsychological assessments at 2.5 and 6.5 years of age, original medical chart reviews, and extended chart reviews was used.

RESULTS: The outcome was identified in 467 (94.5%) of eligible children alive at 1 year of age. Forty-nine (10.5%) children had a lifetime diagnosis of CP, and 37 (76%) were ambulatory. Fourteen (29%) had CP diagnosed after 2.5 years of age, 37 (76%) had at least 1 additional comorbidity, and 27 (55%) had severe disability. The probability for an incomplete evaluation was higher in children with CP compared with children without CP.

CONCLUSIONS: Children born extremely preterm with CP have various comorbidities and often overall severe disability. The importance of long-term follow-up and of obtaining comprehensive outcome information from several sources in children with disabilities is shown.

IMPORTANCE There are concerns that apparently healthy extremely preterm children face a risk of developing motor impairments, such as developmental coordination disorder. OBJECTIVE To evaluate the prevalence of developmental coordination disorder and associated comorbidities in a national cohort of apparently healthy children born at 22 to 26 gestational weeks, compared alongside term-born peers. DESIGN, SETTING, AND PARTICIPANTS This prospective, population-based cohort study included all children who were consecutively born at 22 to 26 gestational weeks in Sweden from April 1, 2004, through March 31, 2007. At 6.5 years, 441 preterm children were evaluated alongside 371 controls. A total of 275 preterm children (62.4%) and 359 term-born children (96.8%) did not have neurodevelopmental disabilities. Motor assessments were completed for 229 of 275 preterm children (83.3%) and 344 of 359 (95.8%) term-born children, who composed the final study sample. MAIN OUTCOMES AND MEASURES Developmental coordination disorder was defined as a score of the fifth percentile or lower on the Movement Assessment Battery for Children-Second Edition scale, using control group scores. Assessment tools included the Wechsler Intelligence Scale for Children-Fourth Edition, the Brown Attention-Deficit Disorder Scales, the Five to Fifteen questionnaire, and the Strengths and Difficulties questionnaire. RESULTS Of the 229 extremely preterm children and 344 term-born controls who underwent motor assessments, 115 (50.2%) and 194 (56.4%) were boys, respectively. Developmental coordination disorder was present in 85 of 229 (37.1%) preterm children and in 19 of 344 controls (5.5%) (adjusted odds ratio [OR], 7.92; 99% CI, 3.69-17.20). When preterm children with developmental coordination disorder were compared with term-born peers, the risk was increased for total behavioral problems, internalizing, externalizing, attentional problems, hyperactivity, perceptual problems, executive dysfunction, and poor social skills, with adjusted ORs varying from 2.66 (99% CI, 1.09-6.48) for time concepts to 9.06 (99% CI, 3.60-22.8) for attentional problems (all P < .01). When preterm children with and without developmental coordination disorder were compared, preterm children with developmental coordination disorder had more behavioral problems; the adjusted OR for total behavioral problems was 2.71 (99% CI, 1.15-6.37); for externalizing problems, 2.80 (99% CI, 1.10-7.12); for inattention, 3.38 (99% CI, 1.39-8.18); and for combined attention/hyperactivity problems, 3.68 (99% CI, 1.47-9.16) (all P < .01). Parents underestimated the children's motor problems and only a few of the children had received psychological care or physiotherapy. CONCLUSIONS AND RELEVANCE Children who were born extremely preterm faced a high risk for developmental coordination disorder with associated comorbidities. Our findings support the importance of a structured follow-up of motor function, behavior, and cognition. 

Aim: More infants born extremely preterm (EPT) are surviving, but major neonatal morbidities are consistently high. This study examined the impact of bronchopulmonary dysplasia (BPD), brain injuries and severe retinopathy of prematurity (ROP) on adolescents who were born EPT.

Methods: We focused on EPT infants born at 23-25 weeks at the Swedish university hospitals in Uppsala and Umea from January 1992 to December 1998. The poor outcome data covered 140 of 142 who survived to 36 weeks, and the chronic conditions data reported by parents covered 132 of 134 still alive at 10-15 years.

Results: Of the 140 survivors at 36 weeks, 29 (21%) had poor outcomes: eight of 140 (6%) died, and 21 of 132 (16%) adolescent survivors had severe neurodevelopmental disabilities (NDD). BPD, severe ROP and/or brain injuries correlated independently with poor outcome. Of those adolescents who were free from BPD, brain injury and severe ROP, 6% had a severe NDD. The corresponding rates with any one, any two or all three neonatal morbidities were 21, 33 and 67%, respectively. BPD and brain injuries were associated with high rates of chronic conditions at 10-15 years of age resulting in functional limitations.

Conclusion: In adolescent EPT survivors, BPD and brain injuries were associated with high rates of chronic conditions and special healthcare needs.

Aim: This study aimed to explain the relationship between visual-motor integration (VMI) abilities and extremely preterm (EPT) birth, by exploring the influence of perinatal variables, cognition, manual dexterity and ophthalmological outcomes. Methods: This was part of the population-based national Extremely Preterm Infant Study in Sweden (EXPRESS) study. We studied 355 children, born at a gestational age of <27 weeks from April 2004 to March 2007, and 364 term-born controls. At six-and-a-half years of age, we assessed VMI, cognitive function, motor skills and vision. VMI impairment was classified as <-1 standard deviation (SD). Results: The mean (SD) VMI score was 87 (+/- 12) in preterm children compared to 98 (+/- 11) in controls (p < 0.001). VMI impairment was present in 55% of preterm infants and in 78% of children born at 22-23 weeks. Male sex and postnatal steroids showed a weak association with poorer visual-motor performance, whereas low manual dexterity and cognitive function showed a stronger association. Conclusion: Poor VMI performance was common in this EXPRESS cohort of children born EPT. Its strong association to cognition and manual dexterity confirms that all of these factors need to be taken into account when evaluating risks in preterm born children.

BACKGROUND: This study examined mental health outcomes in extremely preterm children (EPT) born at 23 to 25 weeks of gestation between 1992 and 1998 at 2 Swedish tertiary care centers that offered regional and active perinatal care to all live-born EPT infants. METHODS; We assessed 132 (98%) of the 134 EPT survivors at 10 to 15 years of age alongside term-born controls. Behavioral and emotional problems were evaluated by using Achenbach's Child Behavior Checklist and Teacher Report Form and Conners' Parent and Teacher scales for attention-deficit/hyperactivity disorder. RESULTS: Parents and teachers reported significantly more problems with internalizing behaviors as well as attention, social, and thought problems in EPT children than in controls, even when those with major neurodevelopmental disabilities (NDDs) were excluded. Multivariate analysis of covariance of the behavioral problems reported by parents and teachers revealed no interactions, hut significant main effects emerged for group status (EPT versus control) and sex, with all effect sizes being medium to large and accounting for 8% to 14% of the variance. Compared with the controls, EPT children without NDDs had significantly increased rates of >= 90th percentile for total Conners' attention-deficit/hyperactivity disorder problem scores (parents: 40% vs 15%, odds ratio: 3.7, P <.001) (teachers: 24% vs 9%, odds ratio: 3.3, P =.005). The corresponding rates were higher in the total population. CONCLUSIONS: EPT children with or without NDDs had behavioral problems characterized by a higher risk for anxiety and attention, social, and thought problems. These findings further strengthen the proposition that a preterm behavioral phenotype is recognizable in adolescents born EPT.