Gestational age and basic school achievements: a national follow-up study in Denmark

Poor socioeconomic outcomes: Completion of the final examination after lower secondary education mitigates risks associated with gestational age

AIM

To investigate the influence of gestational age (GA) on the association between completion of the final examination after 10-11 years of basic education and education, financial independence and income in early adulthood.

METHODS

A nationwide register-based study including individuals born in Denmark between 1990 and 1992. Completion of the examination was evaluated at age 18 and education, financial independence and income at age 28.

RESULTS

Of 165 683 individuals included, 15.7%, 10.8% and 5.5% had low educational level, were not financially independent and had low income. For those who completed the examination odds ratio (OR) ranged from 1.03 at GA = 32-36 weeks to 1.25 at ≤27 weeks for low education, from 1.10 to 0.91 for not being financial independent and from 1.06 to 1.48 for low income. For those who did not complete the examination, OR increased from 7.55 at ≥37 weeks to 15.03 at ≤27 weeks for low education and from 4.68 to 15.31 for not being financial independent. For low income, OR was 2.57 and independent of GA.

CONCLUSION

For individuals who completed the examination, the odds of poor socioeconomic outcomes were independent of GA. Individuals who did not complete the examination had increased odds of poor socioeconomic outcomes, particularly as GA decreased.

Preterm children born below 33-35 weeks of gestation have an increased risk of mathematical difficulties

AIM

To investigate the association between gestational age (GA) and grade point averages by domains of language and mathematics at the end of lower secondary education.

METHODS

A nationwide register-based study including all Danish children born in 1992-1997 who completed lower secondary education. Grades were evaluated by GA. Domain-specific differences in grades were investigated, and academic profiles were made.

RESULTS

The study population comprised 319 796 children. For language, only minor differences in grades were observed. The grades in mathematics ranged from 7.02 (95% confidence interval [CI]: 7.00-7.04) at GA = 40 weeks to 5.86 (95% CI: 5.61-6.11) at GA <28 weeks. Grade differences showed lower grades in mathematics, compared to language, below GA 33-35 weeks. The academic profile of mathematical difficulties was more prevalent among GA <32 weeks. Average/high grades within both domains represented the predominant academic profile, constituting 68.8% at GA 39-41 weeks and 56.6% at GA <28 weeks.

CONCLUSION

Only in mathematics decreasing GA was associated with lower grades. Increased mathematical difficulties were found below GA 33-35 weeks. The academic profile of mathematical difficulties was more prevalent among GA <32 weeks. However, the absolute differences in grades were small, and the predominant academic profile was average/high grades within both domains across all GA.

Spillover effects of gestational age on sibling's literacy

Adverse health events within families can harm children's development, including their early literacy. Using data from a longitudinal Wisconsin birth cohort, we estimated the spillover effect of younger siblings' gestational ages on older siblings' kindergarten-level literacy. We sampled 20,014 sibling pairs born during 2007-2010 who took Phonological Awareness Literacy Screening-Kindergarten tests during 2012-2016. Exposures were gestational age (completed weeks), preterm birth (gestational age <37 weeks), and very preterm birth (gestational age <32 weeks). We used gain-score regression-a fixed effects strategy-to estimate spillover effect. A one-week increase in younger siblings' gestational age improved the older siblings' test score by 0.011 SD (95% confidence interval: 0.001, 0.021 SD). The estimated spillover effect was larger among siblings whose mothers reported having a high school diploma/equivalent only (0.024 SD; 95% CI: 0.004, 0.044 SD). The finding underscores the networked effects of one individual's early-life health shocks on their family members.

Gestational age at birth and cognitive outcomes in adolescence: population based full sibling cohort study

OBJECTIVE

To investigate the association between gestational age at birth and cognitive outcomes in adolescence.

DESIGN

Nationwide population based full sibling cohort study.

SETTING

Denmark.

PARTICIPANTS

1.2 million children born between 1 January 1986 and 31 December 2003, of whom 792 724 had one or more full siblings born in the same period.

MAIN OUTCOME MEASURES

Scores in written language (Danish) and mathematics examinations as graded by masked assessors at the end of compulsory schooling (ninth grade, ages 15-16 years), in addition to intelligence test score at military conscription (predominantly at age 18 years) for a nested sub-cohort of male adolescents. School grades were standardised as z scores according to year of examination, and intelligence test scores were standardised as z scores according to year of birth.

RESULTS

Among 792 724 full siblings in the cohort, 44 322 (5.6%) were born before 37+0 weeks of gestation. After adjusting for multiple confounders (sex, birth weight, malformations, parental age at birth, parental educational level, and number of older siblings) and shared family factors between siblings, only children born at <34 gestational weeks showed reduced mean grades in written language (z score difference -0.10 (95% confidence interval -0.20 to -0.01) for ≤27 gestational weeks) and mathematics (-0.05 (-0.08 to -0.01) for 32-33 gestational weeks, -0.13 (-0.17 to -0.09) for 28-31 gestational weeks, and -0.23 (-0.32 to -0.15) for ≤27 gestational weeks), compared with children born at 40 gestational weeks. In a nested sub-cohort of full brothers with intelligence test scores, those born at 32-33, 28-31, and ≤27 gestational weeks showed a reduction in IQ points of 2.4 (95% confidence interval 1.1 to 3.6), 3.8 (2.3 to 5.3), and 4.2 (0.8 to 7.5), respectively, whereas children born at 34-39 gestational weeks showed a reduction in intelligence of <1 IQ point, compared with children born at 40 gestational weeks.

CONCLUSIONS

Cognitive outcomes in adolescence did not differ between those born at 34-39 gestational weeks and those born at 40 gestational weeks, whereas those with a gestational age of <34 weeks showed substantial deficits in multiple cognitive domains.

Socioeconomic outcomes beyond 30 years of age in a cohort born with very low birth weight

AIM

As survival of infants born prematurely has increased dramatically, questions on long-term consequences have emerged. Our aim was to investigate long-term effects of very low birth weight on socioeconomic outcomes.

METHODS

One hundred and fifty very low birth weight infants (VLBW) born from 1980 to 1982 at Rigshospitalet, Denmark, who had previously been followed up at age 2, 4 and 18 years, were compared to cohorts of low birth weight, normal birth weight (NBW) and a national population-based reference cohort. From the Danish national registers we obtained data regarding educational level, financial independence and living arrangements. In addition, we used the previously published results from the three cohorts.

RESULTS

The VLBW cohort had lower intelligence quotient and higher risk of significant school difficulties evaluated at age 4 and 18 years. When compared to the NBW cohort, at 30-36 years of age the VLBW cohort tended to have lower educational level, OR 1.7, 95% CI 0.8-3.9, were not financially independent OR 1.5, 95% CI 0.6-3.7, lived alone OR 2.0, 95% CI 1.0-3.8 and had higher rates of the combination of all three outcomes, OR 3.2, 95% CI 0.7-15.8.

CONCLUSIONS

We found trends towards poor socioeconomic outcomes in young adults born with VLBW. The relative disadvantages appeared smaller than that in childhood.

Preterm Birth is Associated with Lower Academic Attainment at Age 12 Years: A Matched Cohort Study by Linkage of Population-Based Datasets

OBJECTIVE

To compare academic attainment at age 12 years in preterm children born below 30 weeks of gestation with matched term-born peers, using standardized, nationwide and well-validated school tests.

STUDY DESIGN

This population-based, national cohort study was performed by linking perinatal data from the nationwide Netherlands Perinatal Registry with educational outcome data from Statistics Netherlands and included 4677 surviving preterm children born at 25^0/7-29^6/7 weeks of gestational age and 366 561 controls born at 40 weeks of gestational age in 2000-2007. First, special education participation rate was calculated. Subsequently, all preterm children with academic attainment test data derived at age 12 years were matched to term-born children using year and month of birth, sex, parity, socioeconomic status, and maternal age. Total, language, and mathematics test scores and secondary school level advice were compared between these 2 groups.

RESULTS

Children below 30 weeks of gestation had a higher special education participation rate (10.2% vs 2.7%, P < .001) than term-born peers. Preterm children had lower total (-0.37 SD; 95% CI -0.42 to -0.31), language (-0.21 SD; 95% CI -0.27 to -0.15), and mathematics (-0.45 SD; 95%CI -0.51 to -0.38) z scores, and more often a prevocational secondary school level advice (62% vs 46%, P < .001).

CONCLUSIONS

A substantial proportion of children born before 30 weeks of gestation need special education at the end of elementary schooling. These children have significant deficits on all measures of academic attainment at age 12 years, especially mathematics, compared with matched term-born peers.

The critical importance of follow-up to school age: Contributions of the NICHD Neonatal Research Network

Follow-up studies are essential for understanding outcomes and informing the care of infants with high risk for medical and developmental consequences because of extreme prematurity or perinatal illness. Studies that extend to school age often identify sequelae that go unrecognized in neonatal or short-term follow-up studies. Many critical neurocognitive, behavioral, functional, and health outcomes are best assessed beginning at school age. The Eunice Kennedy Shriver National Institute of Child Health and Development Neonatal Research Network (NRN) has performed comprehensive school age evaluations of several key trial cohorts. This manuscript summarizes the important contributions of school age follow-up studies in the NRN, both historically and in ongoing research. We describe in detail the clinical questions that have been answered by the completed studies and new questions about the outcomes of high-risk infants that must be addressed by ongoing and future studies.

Gestational age at birth and academic attainment in primary and secondary school in England: Evidence from a national cohort study

Preterm birth (<37 weeks’ gestation) is a risk factor for poor educational outcomes. A dose-response effect of earlier gestational age at birth on poor primary school attainment has been observed, but evidence for secondary school attainment is limited and focused predominantly on the very preterm (<32 weeks) population. We examined the association between gestational age at birth and academic attainment at the end of primary and secondary schooling in England. Data for children born in England from 2000–2001 were drawn from the population-based UK Millennium Cohort Study. Information about the child’s birth, sociodemographic factors and health was collected from parents. Attainment on national tests at the end of primary (age 11) and secondary school (age 16) was derived from linked education records. Data on attainment in primary school was available for 6,950 pupils and that of secondary school was available for 7,131 pupils. Adjusted relative risks (aRRs) for these outcomes were estimated at each stage separately using modified Poisson regression. At the end of primary school, 17.7% of children had not achieved the expected level in both English and Mathematics and this proportion increased with increasing prematurity. Compared to full term (39–41 weeks) children, the strongest associations were among children born moderately (32–33 weeks; aRR = 2.13 (95% CI 1.44–3.13)) and very preterm (aRR = 2.06 (95% CI 1.46–2.92)). Children born late preterm (34–36 weeks) and early term (37–38 weeks) were also at higher risk with aRR = 1.18 (95% CI 0.94–1.49) and aRR = 1.21 (95% CI 1.05–1.38), respectively. At the end of secondary school, 45.2% had not passed at least five General Certificate of Secondary Education examinations including English and Mathematics. Following adjustment, only children born very preterm were at significantly higher risk (aRR = 1.26 (95% CI 1.03–1.54)). All children born before full term are at risk of poorer attainment during primary school compared with term-born children, but only children born very preterm remain at risk at the end of secondary schooling. Children born very preterm may require additional educational support throughout compulsory schooling.

Estimating sibling spillover effects with unobserved confounding using gain-scores

PURPOSE

A growing area of research in epidemiology is the identification of health-related sibling spillover effects, or the effect of one individual's exposure on their sibling's outcome. The health within families may be confounded by unobserved factors, rendering identification of sibling spillovers challenging.

METHODS

We demonstrate a gain-score (fixed effects) regression method for identifying exposure-to-outcome spillover effects within sibling pairs in linear models. The method identifies the exposure-to-outcome spillover effect if only one sibling's exposure affects the other's outcome, and it identifies the difference between the spillover effects if both siblings' exposures affect the others' outcomes. The method fails with outcome-to-exposure spillover or with outcome-to-outcome spillover. Analytic results, Monte Carlo simulations, and a brief application demonstrate the method and its limitations.

RESULTS

We estimate the spillover effect of a child's preterm birth on an older sibling's literacy skills, measured by the Phonological Awareness Literacy Screening-Kindergarten test. We analyze 20,010 sibling pairs from a population-wide, Wisconsin-based (United States) birth cohort. Without covariate adjustment, we estimate that preterm birth modestly decreases an older sibling's test score.

CONCLUSIONS

Gain-scores are a promising strategy for identifying exposure-to-outcome spillover effects in sibling pairs while controlling for sibling-invariant unobserved confounding.

The role of parental education on the relationship between gestational age and school outcomes

BACKGROUND

Individuals born preterm may experience difficulties beyond the neonatal period, such as poorer school outcomes. However, whether these outcomes are modified by family factors is less well-known.

OBJECTIVES

To investigate whether parental educational level modify the relationship of gestational age with completion of final examinations and grade point average in compulsory education.

METHODS

This nationwide register-based cohort study included singletons born in Denmark during 1995-2001. We investigated the differences in the associations between gestational age (24-44 weeks) and two school outcomes at 16 years according to parental educational level (lower (≤10 years), intermediate (11-13 years), and higher (>13 years)). Mixed-effect logistic regression and mixed-effect linear regression were used to model completion of final examination and grade point average, respectively.

RESULTS

Of the 425 101 singletons, 4.7% were born before 37 weeks. The risk of not completing final examination increased with shorter gestational age and lower parental educational level. For instance, among adolescents whose parents had a lower educational level, the risk increased from 23.9% (95% CI, 23.1, 24.6) for those born in week 40 to 36.6% (95% CI, 31.5, 42.1) for those born in week 28. For adolescents whose parents had a higher educational level, the corresponding risk increase was 5.9% (95% CI, 5.7, 6.1) to 10.5% (95% CI, 8.6, 12.8), respectively. Grade point average decreased with shorter gestational age in adolescents born before 30 weeks and with lower parental educational level. The associations between gestational age and grade point average were similar across parental educational levels. For completions of final examination, the associations with gestational age were weaker with higher parental educational level.

CONCLUSIONS

Shorter gestational age and lower parental educational level were associated with poorer school outcomes. Our findings suggest that parental educational level mitigates the adverse effects of shorter gestational age on some school outcomes.

Gestational Age at Term and Educational Outcomes at Age Nine

OBJECTIVES

To estimate associations between gestational age (GA) and teacher-reported academic outcomes at age 9 years among children born at term (37-41 weeks).

METHODS

A secondary data analysis of 1405 children participating in a national US birth cohort study was conducted. At age 9 years, students were evaluated by their teachers in the areas of mathematics, science and social studies, and language and literacy. Unadjusted and adjusted logistic regression models of associations between GA and teacher-reported academic outcomes were estimated and neonatal morbidities were explored as potential pathways.

RESULTS

A continuous measure of GA in weeks was significantly associated with above-average rankings in all areas. The associations were similar across outcomes (eg, mathematics [odds ratio (OR): 1.13; confidence interval (CI): 1.02-1.25], science and social studies [OR: 1.13; CI: 1.01-1.26], and language and literacy [OR: 1.16; CI: 1.05-1.28]) in a model that adjusted for child sex, maternal characteristics, and obstetric risk factors and delivery complications. Other specifications indicate a positive association between late term (41 weeks) and mathematics and a negative association between early term (37-38 weeks) and language and literacy, compared with term (39-40). The associations did not appear to operate through neonatal morbidity.

CONCLUSIONS

The findings highlight the importance of GA, even at term. Whereas current guidelines suggest waiting until at least 39 weeks to deliver when possible, our findings add to a small group of studies suggesting that GA through 41 weeks is associated with improvements in some educational outcomes.

Ninth-grade school achievement in Danish children conceived following fertility treatment: a population-based cohort study

OBJECTIVE

To assess whether academic achievement among children conceived following fertility treatment is different from that of children born to fertile women while also considering the underlying infertility.

DESIGN

Population-based cohort study.

SETTING

Denmark.

PATIENT(S)

The study population consisted of all 154,536 firstborn, live-born, singleton children in Denmark between 1995 and 2000 who completed their ninth grade with an examination.

INTERVENTION(S)

The Danish Infertility Cohort was used to identify children conceived after fertility treatment (n = 10,099), and information on mean school marks was obtained from Statistics Denmark.

MAIN OUTCOME MEASURE(S)

Linear regression models were used to estimate mean differences (MDs) and 95% confidence intervals (CIs). Multiple logistic regression models were used to estimate odds ratios (OR) and 95% CI of not passing the ninth-grade examination.

RESULTS

The crude overall mean marks for children conceived after the various fertility treatment procedures were in general higher than in children born to fertile women. However, after adjustment for potential confounders, the overall mean marks were statistically significantly lower for children conceived after the various fertility treatment procedures (e.g., any fertility treatment: MD -0.13; 95% CI -0.18, -0.08) compared with children born to fertile women. Further, children conceived after any fertility treatment had a statistically significant lower crude likelihood of not passing the ninth-grade examination (OR 0.66; 95% CI 0.53, 0.81) compared with children born to fertile women, whereas no difference was observed in the confounder adjusted analyses (OR 1.15; 95% CI 0.89, 1.49). When children born to women requiring fertility assistance but without fertility treatment in the index pregnancy were used as a reference group, no differences in the adjusted overall mean marks and the likelihood of not passing the ninth grade with an examination were observed.

CONCLUSION

Our findings indicate that fertility treatment per se is not associated with lower school marks and the likelihood of not passing the ninth grade with an examination. Hence, we suggest that factors related to both fertility problems and cognitive development may more likely explain the slightly lower academic performance (i.e., modest lower mean marks) among children conceived after fertility treatment.

Alpha-Lactalbumin Enriched Whey Protein Concentrate to Improve Gut, Immunity and Brain Development in Preterm Pigs

Human milk is rich in nutritional factors, such as alpha-lactalbumin (α-Lac), and important for neonatal development, but nutrient supplementation may be required for optimal growth. Using a pig model, we hypothesized that α-Lac-enriched whey protein concentrate (WPC) supplementation improves neonatal development. Cesarean-delivered preterm pigs were fed either dilute bovine milk (REF) or REF milk supplemented with WPC with normal (STANDARD-ALPHA) or high (HIGH-ALPHA) α-Lac. Clinical, gut, immune and cognitive endpoints (open field, T-maze) were assessed and tissues collected at Day 19. The growth of STANDARD-ALPHA and HIGH-ALPHA were higher than REF (31 vs. 19 g/kg/d). Most organ weights, gut, immunity and brain variables were similar between WPC groups. HIGH-ALPHA had a higher bone mineral content, colon microbial diversity and an abundance of specific bacteria and microbial metabolites, and tended to show a faster food transit time (p = 0.07). Relative to REF, WPC pigs showed higher relative organ weights, blood amino acids, blood neutrophil function, and microbial metabolites, but lower brush-border enzyme activities and plasma cortisol. Cognition outcomes did not differ among the groups. In conclusion, WPC supplementation of milk improved some growth, gut and immunity parameters in preterm pigs. However, increasing the α-Lac content beyond human milk levels had limited effects on the immature gut and developing brain.

Gestational age, kindergarten-level literacy, and effect modification by maternal socio-economic and demographic factors

BACKGROUND

Shorter gestational age at birth is associated with worse academic performance in childhood. Socio-economic and demographic factors that affect a child's development may modify the relationship between gestational age and later academic performance.

OBJECTIVE

The purpose of this study was to investigate socio-economic and demographic effect modification of gestational age's association with kindergarten-level literacy skills in a longitudinal Wisconsin birth cohort.

METHODS

We sampled 153 145 singleton births (2007-2010) that linked to Phonological Awareness Literacy Screening-Kindergarten (PALS-K) scores (2012-2016 school years). PALS-K outcomes included meeting the screening benchmark (≥28 points, range 0-102 points) and the standardised score. Multivariable linear regressions of PALS-K outcomes on gestational age (completed weeks) included individual interactions for five maternal attributes measured at delivery: Medicaid coverage, education, age, race/ethnicity, and marital status.

RESULTS

Each additional completed gestational week was associated with a 0.5 percentage point increase in the probability of meeting the PALS-K literacy benchmark. The benefit of an additional week of gestational age was 0.5 percentage points (95% confidence interval 0.3, 0.7 percentage points) greater for Medicaid-covered births (0.8 percentage points) relative to non-Medicaid births (0.3 percentage points). Relative to only completing high school, having college education weakened this association by 0.3-0.6 percentage points, depending on years in college. Similar but modest relations emerged with standardised scores.

CONCLUSIONS

Socio-economic advantage as indicated by non-Medicaid coverage or higher levels of completed maternal education may diminish the cost of preterm birth on a child's kindergarten-level literacy skills.

Improving developmental and educational support for children born preterm: evaluation of an e-learning resource for education professionals

OBJECTIVES

Children born preterm are at higher risk for special educational needs and poor academic attainment compared with term-born peers, yet education professionals receive limited training and have poor knowledge of preterm birth. We have developed an interactive e-learning resource and evaluated its efficacy in improving teachers' knowledge of preterm birth and their confidence in supporting the learning of children born preterm.

SETTING

Eight primary, infant or junior schools in England.

PARTICIPANTS

61 teachers of children aged 4-11 years, of which 55 (90%) were female.

INTERVENTION

Interactive e-learning resource designed to improve education professionals' knowledge of long-term outcomes following preterm birth and strategies that can be used to support children's learning (www.pretermbirth.info). In a repeated measures design, participants were given up to 30 days access to the e-learning resource, before and after which they completed the Preterm Birth Knowledge Scale (PB-KS; scores 0-33; higher scores indicate greater knowledge) to assess knowledge of outcomes of prematurity. Four Likert scale items were used to assess confidence in supporting children's learning and 10 items were used to evaluate the utility of the resource. PB-KS scores and responses on confidence item were compared pre-resource and post-resource use.

RESULTS

PB-KS scores significantly increased after accessing the e-learning resource (median (95% CI): pre-resource 13 (11 to 14); post-resource 29 (28 to 30)), equating to a 2.6 SD increase in PB-KS scores. Teachers' confidence in supporting children born preterm was also significantly improved after using the resource. The utility of the resource was evaluated positively by participants with 97% reporting that they would recommend its use to others.

CONCLUSIONS

The e-learning resource substantially improved teachers' knowledge of preterm birth and their confidence in supporting preterm children in the classroom. Use of this resource may represent a key advance in improving educational outcomes for children born preterm.

Late Preterm Infants: Morbidities, Mortality, and Management Recommendations

Infants born between 34 weeks 0 days and 36 weeks 6 days of gestation are termed late preterm. This group accounts for the majority of premature births in the United States, with rates increasing in each of the last 3 years. This increase is significant given their large number: nearly 280,000 in 2016 alone. Late preterm infants place a significant burden on the health care and education systems because of their increased risk of morbidities and mortality compared with more mature infants. This increased risk persists past the newborn period, leading to the need for continued health monitoring throughout life.

Maternal recurrent pregnancy loss is associated with an increased risk for long-term neurological morbidity in offspring

AIM

To determine whether maternal history of recurrent pregnancy loss (RPL) impacts on the long-term neurological health of the offspring.

METHOD

A population-based cohort analysis was performed, including all singletons born between 1991 and 2014 at a single regional tertiary centre. Neurological morbidity up to age 18 years (including cognitive, motor, and psychiatric disorders) in children born to mothers with and without a history of RPL was compared. Cumulative neurological morbidity incidence was compared with survival curves and a Weibull multivariable survival model to control for follow-up time and relevant confounders.

RESULTS

A total of 242 187 deliveries met the inclusion criteria during the study period, 5% (n=12 182) of which were in mothers with RPL. Epilepsy and developmental disorders were significantly more common in the group with RPL (0.95 vs 0.74/1000 person-years [p=0.009] and 0.22 vs 0.09/1000 person-years [p<0.001]). The survival curves demonstrated significantly higher cumulative incidences of epilepsy and developmental disorders in the group with RPL. The multivariable model exhibited an independent association between maternal RPL and childhood epilepsy (adjusted hazard ratio 1.23; 95% confidence interval 1.01-1.50) and developmental disorders in the offspring (adjusted hazard ratio 2.41; 95% confidence interval 1.60-3.64).

INTERPRETATION

A history of maternal RPL appears to be independently associated with long-term neurological morbidity of the offspring.

WHAT THIS PAPER ADDS

Hospitalizations for epilepsy and developmental disorders are significantly more common among children of mothers with a history of recurrent pregnancy loss.

Gestational Age, Health, and Educational Outcomes in Adolescents

BACKGROUND AND OBJECTIVES

As outcomes for extremely premature infants improve, up-to-date, large-scale studies are needed to provide accurate, contemporary information for clinicians, families, and policy makers. We used nationwide New Zealand data to explore the impact of gestational age on health and educational outcomes through to adolescence.

METHODS

We performed a retrospective cohort study of all births in New Zealand appearing in 2 independent national data sets at 23 weeks' gestation or more. We report on 2 separate cohorts: cohort 1, born January 1, 2005 to December 31, 2015 (613 521 individuals), used to study survival and midterm health and educational outcomes; and cohort 2, born January 1, 1998 to December 31, 2000, and surviving to age 15 years (146 169 individuals), used to study high school educational outcomes. Outcomes described by gestational age include survival, hospitalization rates, national well-being assessment outcomes at age 4 years, rates of special education support needs in primary school, and national high school examination results.

RESULTS

Ten-year survival increased with gestational age from 66% at 23 to 24 weeks to >99% at term. All outcomes measured were strongly related to gestational age. However, most extremely preterm children did not require special educational support and were able to sit for their national high school examinations.

CONCLUSIONS

Within a publicly funded health system, high-quality survival is achievable for most infants born at periviable gestations. Outcomes show improvement with gestational ages to term. Outcomes at early-term gestation are poorer than for children born at full term.

Neurodevelopmental Outcomes of Preterm Children at School Age and Beyond

Despite improved survival of preterm infants, there has not been an equivalent improvement in long-term neurodevelopmental outcomes. Adverse neurodevelopmental outcome rates and severity are inversely related to the degree of prematurity, but only 1.6% are born very preterm and the motor, cognitive, behavioral, and psychiatric disabilities in the large moderate and late preterm population have a greater impact. The disability-free preterm adult has a lower educational achievement and income but similar health-related quality of life to term controls. Reducing the long-term neurodevelopmental impact of prematurity is the next frontier of neonatal care.

The association between school exam grades and subsequent development of bipolar disorder

OBJECTIVE

Prior studies have indicated that both high and low school grades are associated with development of bipolar disorder (BD), but these studies have not adjusted for parental history of mental disorder, which is a likely confounder. Furthermore, the association between school grades and bipolar I disorder (BD-I) has not been studied. Therefore, we aimed to study the association between school exam grades and subsequent development of BD and BD-I while adjusting for parental history of mental disorder.

METHODS

We conducted a register-based nationwide cohort study following 505 688 individuals born in Denmark between 1987 and 1995. We investigated the association between school exam grades and development of BD or BD-I with a Cox model adjusting for family history of mental disorder and other potential confounders.

RESULTS

During follow-up, 900 individuals were diagnosed with BD and 277 of these with BD-I. The risk for BD and BD-I was significantly increased for individuals not having completed the exams at term [adjusted hazard ratio (aHR) for BD (aHR=1.71, 95% CI: 1.43-2.04) and for BD-I (aHR=1.57, 95% CI: 1.13-2.19)]. Also, having low exam grades in mathematics was associated with increased risk of both BD (aHR=2.41, 95% CI: 1.27-4.59) and BD-I (aHR=2.71, 95% CI: 1.41-5.21). Females with very high exam grades in Danish (percentile group>97.7) had a significantly increased risk of BD-I (aHR=2.49, 95% CI: 1.19-5.23).

CONCLUSIONS

The potential to develop BD seems to affect the school results of individuals negatively even before BD is diagnosed - with females having the potential to develop BD-I as a possible exception.

Childhood Infections and Subsequent School Achievement Among 598,553 Danish Children

BACKGROUND

Hospitalizations for infections have been associated with subsequent decreased cognitive ability, but it is uncertain if childhood infections influence subsequent scholastic achievement (SA). We aimed to estimate the association between infections during childhood and SA.

METHODS

Nationwide prospective cohort study including 598,553 children born in Denmark between 1987 and 1997 and their parents. Exposures were hospitalization for infections and treatment with anti-infective agents. Outcomes were completion of ninth grade and ninth grade test scores. Data were analyzed with logistic and linear regression analysis techniques and adjusted for any mental disorder, birthweight, Apgar score, malformations at birth, chronic somatic diseases, first-born child, parental educational level and parental mental disorders.

RESULTS

Hospitalization with infections was linked to lower completion of ninth grade with an odds ratio of 0.82 (95% confidence interval: 0.79-0.85) compared with children without prior hospitalizations for infections. Dose-response relationships were observed with respect to number of hospital contacts for infections and a shorter time since last hospitalization (all P < 0.001). Among those who completed the ninth grade test score, we found a dose-response and time-since relationship between number of prior severe infections and subsequent lower grade scores (P < 0.001). Treatment of nonsevere infections with anti-infective agents did not predict lower completion of ninth grade but was associated with lower grade scores (P < 0.001).

CONCLUSIONS

Infections, particularly those requiring hospitalizations, were associated with subsequent affected cognitive ability as indicated by lower SA. These findings might also be explained by missed school days or socioeconomic factors associated with the susceptibility of acquiring infections.

Low gestational age at birth and difficulties in school-A matter of 'dose'

Objectives

Several studies suggest a relationship between gestational age at birth and risk of school difficulties. Our study aimed to investigate the association between the entire range of gestational ages and significant school difficulties measured as 1) More than nine hours per week special educational support and 2) Failing to complete compulsory school.

Methods

A population-based register study including all children attending the Danish compulsory school in 2015/2016 and all live-born infants born in Denmark from 1992 to 1997. Data were collected and linked using multiple registers held by Statistic Denmark. Multiple logistic regression analyses were used to estimate the association between gestational age and significant school difficulties, adjusted for explanatory variables.

Results

For measurement 1) “Special educational support” 615,789 children entered the analyses after exclusion of those with missing neonatal data. The risk of special educational support increased gradually across the entire range of gestation from 40 to ≤24 weeks: The adjusted odds ratio was 1.07 (95% confidence interval 1.03–1.12) at 39 weeks of gestational and 6.18 (95% confidence interval 5.17–7.39) at gestational ages < 28 weeks. For measurement 2) “Failing to complete compulsory school” the cohort consisted of 374,798 children after exclusion of those who died, had emigrated and/or had missing neonatal data. The risk of failing to complete compulsory school increased across the entire range of gestational ages: The adjusted odds ratio was 1.07 (95% confidence interval 1.04–1.10) at 39 weeks of gestation and 2.99 (95% confidence interval 2.41–3.71) at gestational ages < 28 weeks. In both sets of analyses GA = 40 weeks was used as reference.

Conclusions

We confirm a clear association between the degree of prematurity and significant school difficulties across the entire range of gestational ages from ≤ 24 to 40 weeks.

The impact of prematurity and maternal socioeconomic status and education level on achievement-test scores up to 8th grade

BACKGROUND

The relative influence of prematurity vs. maternal social factors (socioeconomic status and education level) on academic performance has rarely been examined.

OBJECTIVE

To examine the impact of prematurity and maternal social factors on academic performance from 3rd through 8th grade.

METHODS

We conducted a retrospective cohort study of infants born in 1998 at the University of Arkansas for Medical Sciences. The study sample included 58 extremely low gestational age newborns (ELGANs, 23‒<28 weeks), 171 preterm (≥28‒<34 weeks), 228 late preterm (≥34‒<37 weeks), and 967 term ((≥37‒<42 weeks) infants. Neonatal and maternal variables were collected including maternal insurance status (proxy measure for socioeconomic status) and education level. The primary outcomes were literacy and mathematics achievement-test scores from 3rd through 8th grade. Linear mixed models were used to identify significant predictors of academic performance. All two-way interactions between grade level, gestational-age (GA) groups, and social factors were tested for statistical significance.

RESULTS

Prematurity, social factors, gender, race, gravidity, and Apgar score at one minute were critical determinants of academic performance. Favorable social factors were associated with a significant increase in both literacy and mathematic scores, while prematurity was associated with a significant decrease in mathematic scores. Examination of GA categories and social factors interaction suggested that the impact of social factors on test scores was similar for all GA groups. Furthermore, the impact of social factors varied from grade to grade for literacy, while the influence of either GA groups or social factors was constant across grades for mathematics. For example, an ELGAN with favorable social factors had a predicted literacy score 104.1 (P <.001), 98.2 (P <.001), and 76.4 (P <.01) points higher than an otherwise similar disadvantaged term infant at grades 3, 5, and 8, respectively. The difference in their predicted mathematic scores was 33.4 points for all grades (P <.05).

CONCLUSION

While there were significant deficits in academic performance for ELGANs compared to PT, LPT, and term infants, the deficit could be offset by higher SES and better-educated mothers. These favorable social factors were critical to a child's academic achievement. The role of socioeconomic factors should be incorporated in discussions on outcome with families of preterm infants.

Long-duration general anesthesia influences the intelligence of school age children

Background

General anesthesia has been linked to impaired brain development in immature animals and young children. In this study the influence of orthopedic surgery under general anesthesia on the intelligence of school age children has been evaluated.

Methods

A total of 209 subjects aged 6–12 years were recruited and allocated into 4 groups according to the duration of general anesthesia, including a control group (n = 30), short (< 1 h, n = 49), moderate- (1–3 h, n = 51) and long-duration groups (> 3 h, n = 79), respectively. The intelligence quotient (IQ) of the subjects was measured by the Raven’s Standard Progressive Matrices (RSPM) before and after orthopedic surgery under general anesthesia of various durations (vide supra).

Results

The IQ score decreased significantly in the long-duration group at 1 month post-operation compared with the pre-operation score (P < 0.001), and IQ did not recover completely at 3 months postoperatively (P < 0.05), but had recovered when measured at the 1-year follow-up. Moreover, this study showed that the development of children’s intelligence was affected by the exposure time to anesthetics at a younger age (OR = 5.26, 95% CI:2.70–8.41, P < 0.001), having a mother with a low education level (OR = 2.71, 95% CI:1.24–6.14, P = 0.014) and premature birth (OR = 2.76, 95% CI:1.34–5.46, P = 0.005).

Conclusions

More than 3 h general anesthesia influenced the IQ of school age children for up to 3 months after orthopedic surgery. Beside extended exposure time to anesthetics additional factors for post-operative IQ reduction were younger children age, mothers with low educational levels and premature birth.

Trial registration

Chinese Clinical Trial Registry with registration number ChiCTR-OOC-17013497 retrospectively registered on 11/23/2017.

Stability of Developmental Problems after School Entry of Moderately-Late Preterm and Early Preterm-Born Children

OBJECTIVE

To assess the stability of developmental problems in moderately-late preterm-born children compared with early preterm and full term-born children before school entry at age 4 years and 1 year after school entry at age 5 years.

STUDY DESIGN

We included 376 early preterm, 688 born moderately-late preterm, and 403 full term-born children from the Longitudinal Preterm Outcome Project (LOLLIPOP) cohort study. Developmental problems were assessed by the total score and the 5 domain scores of the Ages and Stages Questionnaire at ages 4 (ASQ-4) and 5 (ASQ-5). From the combinations of normal and abnormal ASQ-4 and ASQ-5 scores we constructed 4 categories: consistently normal, emerging, resolving, and persistent problems.

RESULTS

The ASQ-4 total score was abnormal more frequently in moderately-late preterm (7.9%, P = .016) and early preterm-born children (13.0%, P < .001) than in full term-born children (4.1%). Compared with the ASQ-5 total score, moderately-late preterm-born children had persistence and change comparable with full term-born children, and early preterm-born children had significantly greater rates than full term-born children of persistent (8.4% vs 2.2%, P < .001) and emerging problems (7.8% vs 2.7% P = .001). On the underlying domains, both early preterm and moderately-late preterm-born children had mainly emerging motor problems and resolving communication problems, but the changing rates of moderately-late preterm-born children were lower.

CONCLUSIONS

After school entry, the overall development of moderately-late preterm-born children had stability patterns comparable with full term-born children, whereas early preterm-born children had greater rates of persistent and emerging problems. On the underlying domains, moderately-late preterm-born children had patterns comparable with early preterm-born children but at lower rates.

Risk of impaired cognition after prenatal exposure to psychotropic drugs

OBJECTIVE

Prenatal exposure to psychotropic drugs may affect the trajectories of brain development. In a register study, we investigated whether such exposure is associated with long-term impaired cognitive abilities.

METHOD

Individuals born in Denmark in 1995-2008 were included. As proxies for cognitive impairment, requiring special needs education, attending special needs school, diagnoses of neurological/mental disorder, missed final examinations, and low school grade average were used. We accounted for maternal confounders.

RESULTS

We identified 868 159 individuals of whom 13 983 (1.6%) were prenatally exposed. The adjusted odds ratio (OR) was 0.97[0.92-1.02] for requiring special needs education, 1.28[1.14-1.43] for attending special needs school, 1.32[1.20-1.46] for a neurological/mental disorder diagnosis, 1.37[1.22-1.54] for missing the final examinations, and 1.13[0.82-1.55] for obtaining a low school grade average. Exposure to psycholeptics (primarily antipsychotics and sedatives) was correlated with significantly increased risk for four outcomes. The highest was the risk of missing the primary school examinations (OR: 1.51[1.29-1.76]). The overall highest risk concerned the presence of a neurological/mental disorder after prenatal exposure to psychoanaleptics (primarily antidepressants) (OR: 1.86[1.24-2.78).

CONCLUSION

Prenatal exposure to psychotropic drugs affects proxy outcomes of cognitive disabilities at school age. Exposure to psycholeptics carries the largest risk. The role of psychoanaleptics is currently unclear.

Inflammatory and vascular placental lesions are associated with neonatal amplitude integrated EEG recording in early premature neonates

INTRODUCTION

Placental histologic examination can assist in revealing the mechanism leading to preterm birth. Accumulating evidence suggests an association between intrauterine pathological processes, morbidity and mortality of premature infants, and their long term outcome. Neonatal brain activity is increasingly monitored in neonatal intensive care units by amplitude integrated EEG (aEEG) and indices of background activity and sleep cycling patterns were correlated with long term outcome. We hypothesized an association between types of placental lesions and abnormal neonatal aEEG patterns.

OBJECTIVE

To determine the association between the placental lesions observed in extreme preterm deliveries, and their neonatal aEEG patterns and survival.

PATIENTS AND METHODS

This prospective cohort study included extreme premature infants, who were born ≤ 28 weeks of gestation, their placentas were available for histologic examination, and had a continues aEEG, soon after birth)n = 34). Infants and maternal clinical data were collected. aEEG data was assessed for percentage of depressed daily activity in the first 3 days of life and for sleep cycling. Associations of placental histology with clinical findings and aEEG activity were explored using parametric and non-parametric statistics.

RESULTS

Twenty two out of the 34 newborns survived to discharge. Preterm prelabor rupture of membranes (PPROM) or chorioamnionitis were associated with placental lesions consistent with fetal amniotic fluid infection (AFI) or maternal under perfusion (MUP) (P < 0.05). Lesions consistent with fetal response to AFI were associated with absence of SWC pattern during the 1st day of life. Fetal-vascular-thrombo-occlusive lesions of inflammatory type were negatively associated with depressed cerebral activity during the 1st day of life, and with aEEG cycling during the 2nd day of life (P<0.05). Placental lesions associated with MUP were associated with depressed neonatal cerebral activity during the first 3 days of life (P = 0.007).

CONCLUSIONS

Depressed neonatal aEEG patterns are associated with placental lesions consistent with maternal under perfusion, and amniotic fluid infection of fetal type, but not with fetal thrombo-oclusive vascular disease of inflammatory type. Our findings highlight the association between the intrauterine mechanisms leading to preterm parturition and subsequent depressed neonatal cerebral function early after birth, which eventually may put premature infants at risk for abnormal neurodevelopmental outcome.

Time from pre-eclampsia diagnosis to delivery affects future health prospects of children

Background and objectives

Pre-eclampsia often has detrimental health effects for pregnant women and their fetuses, but whether exposure in the womb has long-term health-consequences for children as they grow up remains poorly understood. We assessed overall morbidity of children following exposure to either mild or severe pre-eclampsia up to 30 years after birth and related disease risks to duration of exposure, i.e. the time from diagnosis to delivery.

Methodology

We did a registry-based retrospective cohort study in Denmark covering the years 1979–2009, using the separate diagnoses of mild and severe pre-eclampsia and the duration of exposure as predictor variables for specific and overall risks of later disease. We analysed 3 537 525 diagnoses for 14 disease groups, accumulated by 758 524 singleton children, after subdividing deliveries in six gestational age categories, partialing out effects of eight potentially confounding factors.

Results

Exposure to mild pre-eclampsia appeared to have consistent negative effects on health later in life, although only a few specific disease cases remained significant after corrections for multiple testing. Morbidity risks associated with mild pre-eclampsia were of similar magnitude as those associated with severe pre-eclampsia. Apart from this overall trend in number of diagnoses incurred across disease groups, hazard ratios for several disorders also increased with the duration of exposure, including disorders related to the metabolic syndrome.

Conclusions and implications

Maternal pre-eclampsia has lasting effects on offspring health and differences between exposure to severe and mild pre-eclampsia appear to be less than previously assumed. Our results suggest that it would be prudent to include the long-term health prospects of children in the complex clinical management of mild pre-eclampsia.

Early and long-term outcome of infants born extremely preterm

There is no question that birth at extremely low gestational ages presents a significant threat to an infant's survival, health and development. Growing evidence suggests that gestational age may be conceptualised as a continuum in which births before 28 weeks of gestation (extremely preterm: EP) represent the severe end of a spectrum of health and developmental adversity. Although comprising just 1%-2% of all births, EP deliveries pose the greatest challenge to neonatal medicine and to health, education and social services for the provision of ongoing support for survivors with additional needs. Studying the outcomes of these infants remains critical for evaluating and enhancing clinical care, planning long-term support and for advancing our understanding of the life-course consequences of immaturity at birth. Here we review literature relating to early and long-term neurodevelopmental, cognitive, behavioural and educational outcomes following EP birth focusing on key themes and considering implications for intervention.

Learning disabilities among extremely preterm children without neurosensory impairment: Comorbidity, neuropsychological profiles and scholastic outcomes

BACKGROUND

Children born extremely preterm are at high risk for intellectual disability, learning disabilities, executive dysfunction and special educational needs, but little is understood about the comorbidity of intellectual and learning disabilities in this population.

AIMS

This study explored comorbidity in intellectual disability (ID) and learning disabilities (LD) in children born extremely preterm (EP; <26⁺⁰weeks' gestation).

SUBJECTS AND STUDY DESIGN

A UK national cohort of 161 EP children and 153 term-born controls without neurosensory impairments was assessed at 11years of age (the EPICure Study).

OUTCOME MEASURES

IQ, mathematics and reading attainment, executive function, visuospatial processing and sensorimotor skills were assessed using standardised tests, and curriculum-based attainment and special educational needs (SEN) using teacher reports.

RESULTS

Overall, 75 (47%) EP children and 7 (4.6%) controls had ID or LD (RR 10.12; 95% CI 4.81, 21.27). Comorbidity in ID/LD was more common among EP children than controls (24% vs. 0%). EP children with comorbid ID/LD had significantly poorer neuropsychological abilities and curriculum-based attainment than EP children with an isolated disability or no disabilities. LD were associated with a 3 times increased risk for SEN. However, EP children with ID alone had poorer neuropsychological abilities and curriculum-based attainment than children with no disabilities, yet there was no increase in SEN provision among this group.

CONCLUSIONS

EP children are at high risk for comorbid intellectual and learning disabilities. Education professionals should be aware of the complex nature of EP children's difficulties and the need for multi-domain assessments to guide intervention.

Describing the Shape of the Relationship Between Gestational Age at Birth and Cognitive Development in a Nationally Representative U.S. Birth Cohort

BACKGROUND

Preterm children face higher risk of cognitive and academic deficits compared with their full-term peers. The objective of this study was to describe early childhood cognitive ability and kindergarten academic achievement across gestational age at birth in a population-based longitudinal cohort.

METHODS

The study population included singletons born at 24-42 weeks gestation enrolled in the Early Childhood Longitudinal Study-Birth Cohort (n = 6150 for 2-year outcome, n = 4450 for kindergarten outcome). Home-based assessments measured cognitive ability at 2 years and reading and mathematics achievement at kindergarten age. Linear regression models estimated the association between gestational age and cognitive and academic scores using four different ways of modelling gestational age: continuous variable in linear and quadratic terms; categories for individual weeks; and clinical categories for early preterm, moderate preterm, late preterm, early term, full term, late term, and post-term.

RESULTS

Children born at early preterm (24-27 weeks), moderate preterm (28-33 weeks), and late preterm (34-36 weeks) scored significantly worse than full-term (39-40 weeks) peers on 2-year and kindergarten assessments; however, no deficits were observed for early term (37-38 weeks). These categories were a clinically useful and parsimonious approach to stratifying risk of adverse cognitive and academic outcomes.

CONCLUSIONS

This study estimated the relative performance of children born at 24-42 weeks in a population-based birth cohort using multiple approaches to modelling gestational age, providing a more rigorous understanding of the relationships between the full spectrum of gestational age and cognitive and academic outcomes in early childhood and at school age.

Long-term cognitive and school outcomes of late-preterm and early-term births: a systematic review

BACKGROUND

Children born before full term (39-41 weeks' gestation) are at increased risk of adverse cognitive outcomes. Risk quantification is important as late-preterm (LPT; 34-36 weeks) and early-term (ET; 37-38 weeks) births are common.

METHOD

This review analyses the effect of LPT and ET births on long-term cognitive and educational outcomes. The primary outcome was general cognitive ability. Secondary outcomes included verbal/non-verbal intelligence quotient, subject-specific school performance and special educational needs. The search strategy included Medline and Embase from January 1975 to June 2013. Eligible studies investigated specified outcomes and included suitable gestational age participants assessed at 2 years and older. Outcome measures and socio-demographic descriptors were extracted, and data meta-analysed where possible.

RESULTS

Eight studies compared ET birth with full-term birth. Fourteen studies compared LPT birth with either term birth (>37 weeks, n = 12 studies) or full-term birth (39-41 weeks, n = 2 studies). Substantial between-study heterogeneity existed. LPT and ET children underperformed in most outcomes compared with their term/full-term counterparts, respectively. For example, LPT children had an increased risk of lower general cognitive ability (adjusted risk ratio 1.38 [95% confidence interval 1.06-1.79]), and full-term children performed 5% of a standard deviation higher (z-score 0.05 [0.02, 0.08]) than ET children. Poorer outcomes persist into adulthood; term cohorts performed 5% of a standard deviation higher than LPT cohorts (z-score 0.05 [0.04, 0.07]), and full-term cohorts performed 3% of a standard deviation higher than ET cohorts (z-score 0.03 [0.02, 0.04]).

CONCLUSION

This review critically examines the knowledge around long-term cognitive outcomes of LPT and ET births, demonstrating multiple, small, adverse differences between LPT/ET and term/full-term births.

Delayed growth, motor function and learning in preterm pigs during early postnatal life

Preterm birth interrupts normal fetal growth with consequences for postnatal growth and organ development. In preterm infants, many physiological deficits adapt and disappear with advancing postnatal age, but some may persist into childhood. We hypothesized that preterm birth would induce impaired organ growth and function during the first postnatal week in pigs, while motor abilities and behavioral characteristics would show more persistent developmental delay. Cesarean-delivered preterm ( n = 112, 90% gestation) or term ( n = 56, 100% gestation) piglets were reared under identical conditions and euthanized for blood and organ collection on postnatal days 0, 5, or 26. Body weight gain remained lower in preterm vs. term pigs up to day 26 (25.5 ± 1.5 vs. 31.0 ± 0.5 g·kg−1·day−1, P < 0.01) when relative weights were higher for brain and kidneys and reduced for liver and spleen. Neonatal preterm pigs had reduced values for blood pH, Po2, glucose, lactate, hematocrit, and cortisol, but at day 26, most values were normalized, although plasma serotonin and IGF 1 levels remained reduced. Preterm pigs showed delayed neonatal arousal and impaired physical activity, coordination, exploration, and learning, relative to term pigs (all P < 0.05). Supplementation of parenteral nutrition during the first 5 days with an enteral milk diet did not affect later outcomes. In preterm pigs, many physiological characteristics of immaturity disappeared by 4 wk, while some neurodevelopmental deficits remained. The preterm pig is a relevant animal model to study early dietary and pharmacological interventions that support postnatal maturation and neurodevelopment in preterm infants.

Towards reducing variations in infant mortality and morbidity: a population-based approach

Background

Our aims were (1) to improve understanding of regional variation in early-life mortality rates and the UK’s poor performance in international comparisons; and (2) to identify the extent to which late and moderately preterm (LMPT) birth contributes to early childhood mortality and morbidity.

Objective

To undertake a programme of linked population-based research studies to work towards reducing variations in infant mortality and morbidity rates.

Design

Two interlinked streams: (1) a detailed analysis of national and regional data sets and (2) establishment of cohorts of LMPT babies and term-born control babies.

Setting

Cohorts were drawn from the geographically defined areas of Leicestershire and Nottinghamshire, and analyses were carried out at the University of Leicester.

Data sources

For stream 1, national data were obtained from four sources: the Office for National Statistics, NHS Numbers for Babies, Centre for Maternal and Child Enquiries and East Midlands and South Yorkshire Congenital Anomalies Register. For stream 2, prospective data were collected for 1130 LMPT babies and 1255 term-born control babies.

Main outcome measures

Detailed analysis of stillbirth and early childhood mortality rates with a particular focus on factors leading to biased or unfair comparison; review of clinical, health economic and developmental outcomes over the first 2 years of life for LMPT and term-born babies.

Results

The deprivation gap in neonatal mortality has widened over time, despite government efforts to reduce it. Stillbirth rates are twice as high in the most deprived as in the least deprived decile. Approximately 70% of all infant deaths are the result of either preterm birth or a major congenital abnormality, and these are heavily influenced by mothers’ exposure to deprivation. Births at < 24 weeks’ gestation constitute only 1% of all births, but account for 20% of infant mortality. Classification of birth status for these babies varies widely across England. Risk of LMPT birth is greatest in the most deprived groups within society. Compared with term-born peers, LMPT babies are at an increased risk of neonatal morbidity, neonatal unit admission and poorer long-term health and developmental outcomes. Cognitive and socioemotional development problems confer the greatest long-term burden, with the risk being amplified by socioeconomic factors. During the first 24 months of life each child born LMPT generates approximately £3500 of additional health and societal costs.

Conclusions

Health professionals should be cautious in reviewing unadjusted early-life mortality rates, particularly when these relate to individual trusts. When more sophisticated analysis is not possible, babies of < 24 weeks’ gestation should be excluded. Neonatal services should review the care they offer to babies born LMPT to ensure that it is appropriate to their needs. The risk of adverse outcome is low in LMPT children. However, the risk appears higher for some types of antenatal problems and when the mother is from a deprived background.

Future work

Future work could include studies to improve our understanding of how deprivation increases the risk of mortality and morbidity in early life and investigation of longer-term outcomes and interventions in at-risk LMPT infants to improve future attainment.

Funding

The National Institute for Health Research Programme Grants for Applied Research programme.

Neurodevelopmental outcomes following late and moderate prematurity: a population-based cohort study

OBJECTIVE

There is a paucity of data relating to neurodevelopmental outcomes in infants born late and moderately preterm (LMPT; 32(+0)-36(+6) weeks). This paper present the results of a prospective, population-based study of 2-year outcomes following LMPT birth.

DESIGN

1130 LMPT and 1255 term-born children were recruited at birth. At 2 years corrected age, parents completed a questionnaire to assess neurosensory (vision, hearing, motor) impairments and the Parent Report of Children's Abilities-Revised to identify cognitive impairment. Relative risks for adverse outcomes were adjusted for sex, socio-economic status and small for gestational age, and weighted to account for over-sampling of term-born multiples. Risk factors for cognitive impairment were explored using multivariable analyses.

RESULTS

Parents of 638 (57%) LMPT infants and 765 (62%) controls completed questionnaires. Among LMPT infants, 1.6% had neurosensory impairment compared with 0.3% of controls (RR 4.89, 95% CI 1.07 to 22.25). Cognitive impairments were the most common adverse outcome: LMPT 6.3%; controls 2.4% (RR 2.09, 95% CI 1.19 to 3.64). LMPT infants were at twice the risk for neurodevelopmental disability (RR 2.19, 95% CI 1.27 to 3.75). Independent risk factors for cognitive impairment in LMPT infants were male sex, socio-economic disadvantage, non-white ethnicity, preeclampsia and not receiving breast milk at discharge.

CONCLUSIONS

Compared with term-born peers, LMPT infants are at double the risk for neurodevelopmental disability at 2 years of age, with the majority of impairments observed in the cognitive domain. Male sex, socio-economic disadvantage and preeclampsia are independent predictors of low cognitive scores following LMPT birth.

The long-term consequences of preterm birth: what do teachers know?

AIM

The knowledge and information needs of education professionals were assessed to determine how prepared they feel to support the growing number of preterm children entering schools today.

METHOD

In a national survey, 585 teachers and 212 educational psychologists completed the Preterm Birth-Knowledge Scale (PB-KS) to assess knowledge of outcomes following preterm birth. Total scores (range 0-33) were compared between groups and the impact of demographic characteristics on knowledge was analysed. Training and information needs were also assessed.

RESULTS

Teaching staff (mean 14.7, SD 5.5) had significantly lower knowledge scores than educational psychologists (mean 17.1, SD 5.0; p<0.001); both had significantly lower scores than neonatal clinicians surveyed previously (mean 26.0, SD 3.6; p<0.001). Education professionals' poorest areas of knowledge related to the most frequent adverse outcomes following preterm birth. Only 16% of teaching staff had received training about preterm birth and more than 90% requested more information. Having a special educational needs role and being employed at least 16 years were associated with higher knowledge scores.

INTERPRETATION

Education professionals have poor knowledge of the needs of children born preterm and most feel ill-equipped to support them in school. As teachers have primary responsibility for providing long-term support for children born preterm, this is of significant public health and educational concern.

Systematic Review of Cerebral Palsy Registries/Surveillance Groups: Relationships between Registry Characteristics and Knowledge Dissemination

The aims of this study were to provide a comprehensive summary of the body of research disseminated by Cerebral Palsy (CP) registries and surveillance programs from January 2009 through May 2014 in order to describe the influence their results have on our overall understanding of CP. Secondly, registries/surveillance programs and the work they produced were evaluated and grouped using standardized definitions and classification systems.

METHOD

A systematic review search in PubMed, CINAH and Embase for original articles published from 1 January 2009 to 20 May 2014 originating from or supported by population based CP registries and surveillance programs or population based national registries including CP were included. Articles were grouped by 2009 World CP Registry Congress aim, registry/surveillance program classification, geographical region, and the International Classification of Function, Disability and Health (ICF) domain. Registry variables were assessed using the ICF-CY classification.

RESULTS

Literature searches returned 177 articles meeting inclusion criteria. The majority (69%) of registry/surveillance program productivity was related to contributions as a Resource for CP Research. Prevention (23%) and Surveillance (22%) articles were other areas of achievement, but fewer articles were published in the areas of Planning (17%) and Raising the Profile of CP (2%). There was a range of registry/surveillance program classifications contributing to this productivity, and representation from multiple areas of the globe, although most of the articles originated in Europe, Australia, and Canada. The domains of the ICF that were primarily covered included body structures and function at the early stages of life. Encouragingly, a variety of CP registry/surveillance program initiatives included additional ICF domains of participation and environmental and personal factors.

INTERPRETATION

CP registries and surveillance programs, including novel non-traditional ones, have significantly contributed to the understanding of how CP affects individuals, families and society. Moving forward, the global CP registry/surveillance program community should continue to strive for uniformity in CP definitions, variables collected and consistency with international initiatives like the ICF so that databases can be consolidated for research use. Adaptation to new technologies can improve access, reduce cost and facilitate information transfer between registrants, researchers and registries/surveillance programs. Finally, increased efforts in documenting variables of individuals with CP into adulthood should be made in order to expand our understanding of CP across the lifespan.

School performance at age 7 years in late preterm and early term birth: a cohort study

OBJECTIVE

To investigate the effect of gestational age, particularly late preterm birth (34-36 weeks gestation) and early term birth (37-38 weeks gestation) on school performance at age 7 years.

DESIGN

Population-based prospective UK Millennium Cohort Study, consisting of linked educational data on 6031 children.

METHODS

School performance was investigated using the statutory Key Stage 1 (KS1) teacher assessments performed in the third school year in England. The primary outcome was not achieving the expected level (≥level 2) of general performance in all three key subjects (reading, writing and mathematics). Other outcomes investigated subject-specific performance and high academic performance (level 3).

RESULTS

18% of full-term children performed below the expected KS1 general level, and risk of poor performance increased with prematurity: compared to children born at full-term, there was a statistically significant increased risk of poor performance in those born very preterm (<32 weeks gestation, adjusted RR 1.78, 95% CI 1.24 to 2.54), moderately preterm (32-33 weeks gestation, adjusted RR 1.71, 95% CI 1.15 to 2.54) and late preterm (34-36 weeks gestation, adjusted RR 1.36, 95% CI 1.09 to 1.68). Early term children performed statistically significantly worse in 4 out of 5 individual subject domains than full-term children, but not in the primary outcome (adjusted RR 1.07, 95% CI 0.94 to 1.23).

CONCLUSIONS

Late preterm, and to a lesser extent, early term birth negatively impact on academic outcomes at 7 years as measured by KS1 assessments.

Cognitive abilities in preterm and term-born adolescents

OBJECTIVE

To investigate the influence of a range of prenatal and postnatal factors on cognitive development in preterm and term-born adolescents.

STUDY DESIGN

Woodcock-Johnson III Tests of Cognitive Abilities were used to assess general intellectual ability and 6 broad cognitive abilities in 145 young adolescents aged approximately 12.5 years and born 25-41 weeks gestational age (GA). To study potential links between neurophysiologic and cognitive outcomes, corticomotor excitability was measured using transcranial magnetic stimulation and surface electromyography. The influence of various prenatal and postnatal factors on cognitive development was investigated using relative importance regression modeling.

RESULTS

Adolescents with greater GA tended to have better cognitive abilities (particularly general intellectual ability, working memory, and cognitive efficiency) and higher corticomotor excitability. Corticomotor excitability explained a higher proportion of the variance in cognitive outcome than GA. But the strongest predictors of cognitive outcome were combinations of prenatal and postnatal factors, particularly degree of social disadvantage at the time of birth, birthweight percentile, and height at assessment.

CONCLUSIONS

In otherwise neurologically healthy adolescents, GA accounts for little interindividual variability in cognitive abilities. The association between corticomotor excitability and cognitive performance suggests that reduced connectivity, potentially associated with brain microstructural abnormalities, may contribute to cognitive deficits in preterm children. It remains to be determined if the effects of low GA on cognitive outcomes attenuate over childhood in favor of a concomitant increase in the relative importance of heritability, or alternatively, if cognitive development is more heavily influenced by the quality of the postnatal environment.

Effect of preterm birth on motor development, behavior, and school performance of school-age children: a systematic review

OBJECTIVES

to examine and synthesize the available knowledge in the literature about the effects of preterm birth on the development of school-age children.

SOURCES

this was a systematic review of studies published in the past ten years indexed in MEDLINE/Pubmed, MEDLINE/BVS; LILACS/BVS; IBECS/BVS; Cochrane/BVS, CINAHL, Web of Science, Scopus, and PsycNET in three languages (Portuguese, Spanish, and English). Observational and experimental studies that assessed motor development and/or behavior and/or academic performance and whose target-population consisted of preterm children aged 8 to 10 years were included. Article quality was assessed by the Strengthening the reporting of observational studies in epidemiology (STROBE) and Physiotherapy Evidence Database (PEDro) scales; articles that did not achieve a score of 80% or more were excluded.

SUMMARY OF FINDINGS

the electronic search identified 3,153 articles, of which 33 were included based on the eligibility criteria. Only four studies found no effect of prematurity on the outcomes (two articles on behavior, one on motor performance and one on academic performance). Among the outcomes of interest, behavior was the most searched (20 articles, 61%), followed by academic performance (16 articles, 48%) and motor impairment (11 articles, 33%).

CONCLUSION

premature infants are more susceptible to motor development, behavior and academic performance impairment when compared to term infants. These types of impairments, whose effects are manifested in the long term, can be prevented through early parental guidance, monitoring by specialized professionals, and interventions.

Preterm birth-associated neurodevelopmental impairment estimates at regional and global levels for 2010

BACKGROUND

In 2010, there were an estimated 15 million preterm births worldwide (<37 wk gestation). Survivors are at risk of adverse outcomes, and burden estimation at global and regional levels is critical for priority setting.

METHODS

Systematic reviews and meta-analyses were undertaken to estimate the risk of long-term neurodevelopmental impairment for surviving preterm babies according to the level of care. A compartmental model was used to estimate the number of impaired postneonatal survivors following preterm birth in 2010. A separate model (DisMod-MR) was used to estimate years lived with disability (YLDs) for the global burden of disease 2010 study. Disability adjusted life years (DALYs) were calculated as the sum of YLDs and years of life lost (YLLs).

RESULTS

In 2010, there were an estimated 13 million preterm births who survived beyond the first month. Of these, 345,000 (2.7%, uncertainty range: 269,000-420,000) were estimated to have moderate or severe neurodevelopmental impairment, and a further 567,000 (4.4%, (445,000-732,000)) were estimated to have mild neurodevelopmental impairment. Many more have specific learning or behavioral impairments or reduced physical or mental health. Fewest data are available where the burden is heaviest. Preterm birth was responsible for 77 million DALYs, 3.1% of the global total, of which only 3 million were YLDs.

CONCLUSION

Most preterm births (>90%) survive without neurodevelopmental impairment. Developing effective means of prevention of preterm birth should be a longer term priority, but major burden reduction could be made immediately with improved coverage and quality of care. Improved newborn care would reduce mortality, especially in low-income countries and is likely to reduce impairment in survivors, particularly in middle-income settings.

Determinants of developmental coordination disorder in 7-year-old children: a study of children in the Danish National Birth Cohort

AIM

The aim of this study was to investigate early life determinants of developmental coordination disorder (DCD) in 7-year-old children.

METHOD

The study was based on data from 33,354 women and their children who participated in the 7-year follow-up study of the Danish National Birth Cohort. Information on several potential determinants (maternal age at conception, maternal occupational status, smoking and alcohol consumption during pregnancy, child's sex, intrauterine growth restriction, degree of preterm birth, and age at walking) was obtained from population registries, from interviews during pregnancy and when the child was 18 months old. The outcome in this study was DCD at 7 years of age, measured by the validated Developmental Coordination Disorder Questionnaire. The associations between the potential determinants and DCD were estimated using logistic regression.

RESULTS

The study population consisted of 17,065 males and 16,289 females (141 [0.4%] born very preterm [23(+0)-31(+6) wk]; 1281 [3.8%] born moderately preterm [32(+0)-36(+6) wk]; 29,044 [87.1%] were born term [37(+0)-41(+6) wk], and 2888 [8.7%] were born post-term [≥ 42(+0) wk]). Independently of each other, the following determinants were predictors of DCD: being a female (odds ratio [OR] 0.36 [95% confidence interval {CI} 0.31-0.41]); being born very preterm (OR 6.28 [95% CI 3.99-9.89]) or moderately preterm (OR 2.10 [95% CI 1.65-2.67]); being small for gestational age (OR 1.74 [95% CI 1.46-2.08]); being 15 months of age or more at walking attainment (OR 3.05 [95% CI 2.57-3.60]); and maternal occupational status (higher grade professionals (OR 1.28 [95% CI 1.02-1.61); economically inactive (OR 1.43 [95% CI 1.07-1.91]). Young maternal age and smoking were risk factors among term-born children.

INTERPRETATION

The risk of DCD increases with decreasing gestational age. Intrauterine growth restriction is also a strong risk factor, as well as delayed walking.

Gestational age and cognitive ability in early childhood: a population-based cohort study

BACKGROUND

Recent studies suggest that children born at late preterm (34-36 weeks gestation) and early term (37-38 weeks) may have poorer developmental outcomes than children born at full term (39-41 weeks). We examined how gestational age is related to cognitive ability in early childhood using the U.K. Millennium Cohort Study.

METHODS

Cognitive development was assessed using Bracken School Readiness Assessment at age 3 years, British Ability Scales II at ages 3, 5 and 7 years and Progress in Mathematics at age 7 years. Sample size varied according to outcome between 12,163 and 14,027. Each gestational age group was compared with the full-term group using differences in z-scores and risk ratios for scoring more than -1 SD below the mean.

RESULTS

Children born at <32 weeks gestation scored lower (P < 0.05) than the full-term group on all scales with unadjusted z-score differences ranging between -0.8 to -0.2 SD. In all groups, there was an increased risk (P < 0.05) of scoring less than -1 SD below the mean compared with the full-term group for some of the tests: those born at < 32 weeks had a 40-140% increased risk in seven tests, those born at 32-33 weeks had a 60-80% increased risk in three tests, those born at 34-36 weeks had a 30-40% increased risk in three tests, and those born at 37-38 weeks had a 20% increased risk in two tests.

CONCLUSIONS

Cognitive ability is related to the entire range of gestational age, including children born at 34-36 and 37-38 weeks gestation.

Neurological and developmental outcome in extremely preterm children born in England in 1995 and 2006: the EPICure studies

OBJECTIVE

To determine outcomes at age 3 years in babies born before 27 completed weeks' gestation in 2006, and to evaluate changes in outcome since 1995 for babies born between 22 and 25 weeks' gestation.

DESIGN

Prospective national cohort studies, EPICure and EPICure 2.

SETTING

Hospital and home based evaluations, England.

PARTICIPANTS

1031 surviving babies born in 2006 before 27 completed weeks' gestation. Outcomes for 584 babies born at 22-25 weeks' gestation were compared with those of 260 surviving babies of the same gestational age born in 1995.

MAIN OUTCOME MEASURES

Survival to age 3 years, impairment (2008 consensus definitions), and developmental scores. Multiple imputation was used to account for the high proportion of missing data in the 2006 cohort.

RESULTS

Of the 576 babies evaluated after birth in 2006, 13.4% (n=77) were categorised as having severe impairment and 11.8% (n=68) moderate impairment. The prevalence of neurodevelopmental impairment was significantly associated with length of gestation, with greater impairment as gestational age decreased: 45% at 22-23 weeks, 30% at 24 weeks, 25% at 25 weeks, and 20% at 26 weeks (P<0.001). Cerebral palsy was present in 83 (14%) survivors. Mean developmental quotients were lower than those of the general population (normal values 100 (SD 15)) and showed a direct relation with gestational age: 80 (SD 21) at 22-23 weeks, 87 (19) at 24 weeks, 88 (19) at 25 weeks, and 91 (18) at 26 weeks. These results did not differ significantly after imputation. Comparing imputed outcomes between the 2006 and 1995 cohorts, the proportion of survivors born between 22 and 25 weeks' gestation with severe disability, using 1995 definitions, was 18% (95% confidence interval 14% to 24%) in 1995 and 19% (14% to 23%) in 2006. Fewer survivors had shunted hydrocephalus or seizures. Survival of babies admitted for neonatal care increased from 39% (35% to 43%) in 1995 to 52% (49% to 55%) in 2006, an increase of 13% (8% to 18%), and survival without disability increased from 23% (20% to 26%) in 1995 to 34% (31% to 37%) in 2006, an increase of 11% (6% to 16%).

CONCLUSION

Survival and impairment in early childhood are both closely related to gestational age for babies born at less than 27 weeks' gestation. Using multiple imputation to account for the high proportion of missing values, a higher proportion of babies admitted for neonatal care now survive without disability, particularly those born at gestational ages 24 and 25 weeks.