School performance after preterm birth

Preterm birth and subsequent intelligence and academic performance in youth: A cohort study

INTRODUCTION

Worldwide, more children than before survive preterm birth. Preterm birth can affect long-term cognitive outcomes. The aim of our study was to investigate the association between preterm birth and academic performance and intelligence in youth.

MATERIAL AND METHODS

This cohort study included all liveborn children in Denmark from 1978 to 2000. We used uni- and multivariable logistic and linear regressions to analyze associations between gestational age and school graduation, grade point average (GPA), attending conscription, and male intelligence scores at conscription. We adjusted for a priori defined potential confounders.

RESULTS

The study included 1 450 681 children and found an association between preterm birth and lower academic performance, with children born extremely preterm having the lowest odds of graduating from lower- and upper secondary education (LSE and USE) and appearing before the conscription board (odds ratios of 0.45 [0.38-0.54], 0.52 [0.46-0.59], and 0.47 [0.39-0.56] for LSE, USE, and conscription, respectively, compared to the term group). Statistically significant differences were observed in LSE for total GPA and core subject GPA with higher GPAs in the term group, which were considered clinically relevant for mathematics with a 0.71 higher grade point for the term compared to the extremely preterm. Conversely, USE differences were less evident, and in linear regression models we found that preterm birth was associated with higher GPAs in the adjusted analyses; however, this was not statistically significant. We demonstrated statistically significant differences in intelligence scores at conscription with lower scores in the three preterm groups (-5.13, -2.73, and - 0.76, respectively) compared to the term group.

CONCLUSIONS

Low gestational age at birth was associated with not graduating from LSE and USE, achieving lower GPAs in LSE, not attending conscription, and lower intelligence scores in young adulthood. The findings remained significant after adjusting for potential confounders.

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.

Gestational age and socio-demographic factors associated with school performance at the age of 12 years, a population-based study

BACKGROUND

Gestational age is positively associated with cognitive development, but socio-demographic factors also influence school performance. Previous studies suggested possible interaction, putting children with low socio-economic status (SES) at increased risk of the negative effects of prematurity.

OBJECTIVES

To investigate the association between gestational age in weeks, socio-demographic characteristics, and school performance at the age of 12 years among children in regular primary education.

METHODS

Population-based cohort study among liveborn singletons (N = 860,332) born in the Netherlands in 1999-2006 at 25-42 weeks' gestation, with school performance from 2011 to 2019. Regression analyses were conducted investigating the association of gestational age and sociodemographic factors with school performance and possible interaction.

RESULTS

School performance increased with gestational age up to 40 weeks. This pattern was evident across socio-demographic strata. Children born at 25 weeks had -0.57 SD (95% confidence interval -0.79, -0.35) lower school performance z-scores and lower secondary school level compared to 40 weeks. Low maternal education, low maternal age, and non-European origin were strongly associated with lower school performance. Being born third or later and low socioeconomic status (SES) were also associated with lower school performance, but differences were smaller than among other factors. When born preterm, children from mothers with low education level, low or high age, low SES or children born third or later were at higher risk for lower school performance compared to children of mothers with intermediate education level, aged 25-29 years, with intermediate SES or first borns (evidence of interaction).

CONCLUSIONS

Higher gestational age is associated with better school performance at the age of 12 years along the entire spectrum of gestational age, beyond the cut-off of preterm birth and across socio-demographic differences. Children in socially or economically disadvantaged situations might be more vulnerable to the negative impact of preterm birth. Other important factors in school performance are maternal education, maternal age, ethnicity, birth order and SES. Results should be interpreted with caution due to differential loss to follow-up.

Assessing Behavioral Disorders with SDQ in Very Preterm Children at 5 Years of Age in LIFT Cohort

BACKGROUND

Preterm-born children are at risk of behavioral disorders and the systematic assessment of these disorders remains a challenge. Questions remain about the accuracy of self-reported parent questionnaires and the real everyday life behavior of the child.

AIM

To evaluate the association between SDQ reported by parents in the preterm and behavioral difficulties in the everyday school life environment reported by teacher.

METHODS

All children born before 33 weeks and who followed-up in the LIFT (Loire Infant Follow-up team) network were included. The Strengths and Difficulties Parental Questionnaire (SDQ), completed at 5 years, was used to check for behavioral difficulties and identified three groups: "normal", "borderline" and "abnormal". Then, the SDQ results were compared to the Global School Adaptation Score (GSA) at 5 years.

RESULTS

Out of the 1825 children followed in the cohort at the age of 5, 1397 questionnaires were analyzed. A total of 11.1% of children had an abnormal score, and 9.7% had a borderline score. Male gender and a lower birth weight z-score were significantly associated with the "abnormal SDQ" group. There is a significant relationship between the probability of being in the "abnormal SDQ" group at 5 years and with difficulty in global school adaptation at 5 years, as well as an SDQ borderline score in the preterm (p < 0.001).

CONCLUSIONS

SDQ abnormal and borderline scores are associated with behavioral difficulties in the classroom and everyday life behavior. In preterm children, one should be alerted even by a borderline SDQ score.

Birthweight, gestational age, and early school trajectory

BACKGROUND

Birthweight and gestational age are important factors of not only newborn health by also child development and can contribute to delayed cognitive abilities. However, no study has analyzed the association of birthweight and gestational age with school trajectory measured simultaneously by school entry, grade repetition, and school dropout. This study aims, first, to analyze the association of birthweight or gestational age with school entry, and second, to explore the relationship between birthweight or gestational age and grade repetition and school dropout among children in Ouagadougou, Burkina Faso.

METHODS

This study used longitudinal data from the Ouagadougou Health and Demographic Surveillance System. Our samples consisted of children born between 2008 and 2014 who were at least three years old at the beginning of the 2017-18 school year. Samples included 13,676, 3152, and 3498 children for the analysis of the school entry, grade repetition, and dropout, respectively. A discrete-time survival model was used to examine the relationship between birthweight or gestational age and school entry, grade repetition, and dropout. The association between birthweight or gestational age and age at school entry were assessed using a Poisson regression.

RESULTS

The incidence rate of school entry was 18.1 per 100 people-years. The incidence of first repetition and dropout were 12.6 and 5.9, respectively. The probability of school entry decreased by 31% (HR:0.69, 95%CI: 0.56-0.85) and 8% (HR:0.92, 95%CI: 0.85-0.99) for children weighing less than 2000 g and those weighing between 2000 and 2499 g, respectively, compared to those born with a normal weight (weight ≥ 2500 g). The age at school entry of children with a birthweight less than 2000 g and between 2000 and 2499 g was 7% (IRR: 1.07, 95%CI: 1.06-1.08) and 3% (IRR: 1.03, 95%CI: 1.00-1.06) higher than children born at a normal birthweight, respectively. Gestational age was not associated with school entry or age at school entry. Similarly, birthweight and gestational age were not associated with grade repetition or dropout.

CONCLUSION

This study shows that low birthweight is negatively associated with school entry and age at school entry in Ouagadougou. Efforts to avoid low birthweights should be part of maternal and prenatal health care because the associated difficulties may be difficult to overcome later in the child's life. Further longitudinal studies are needed to better understand the relationship between development at birth and school trajectory.

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.

Predictors of educational failure at 16 and 19 years of age-SESBiC longitudinal study

BACKGROUND

Educational attainment is highly associated with future health and independence. Throughout childhood, children are exposed to factors that may promote educational attainment and factors that may be associated with a reduced likelihood of being able to complete their education. The purpose of the current study was to investigate which factors, measured from birth up to finishing upper secondary school, were associated with a lower mean grade point average from lower and upper secondary school as well as eligibility to upper secondary school and college/university.

METHODS

This is a longitudinal study on 1723 children born in 1995/1996 who have been followed until they were 20 years old. Information with respect to maternal sociodemographics, maternal stress factors during pregnancy and childhood, birth characteristics of the child, child behavior at 3 and 12 years of age, and mean grade point average from lower and upper secondary school, including eligibility to upper secondary school and college/university was collected.

RESULTS

Children exhibiting high problems scores on the child behavior checklist at 12 years of age and children or having other living arrangements (e.g. foster parents or institutional care) were less likely to fulfill the requirements for upper secondary school (OR = 0.35, 95% CI = 0.17-0.71 and OR = 0.33 95% CI = 0.17-0.65, respectively). The likelihood of fulfilling the requirements to college/university was lower if the child had divorced parents at three years of age (OR = 0.30, 95% CI = 0.16-0.58) and exhibited externalizing problems at 12 years of age (OR = 0.45, 95% CI = 0.24-0.86) and if the mother had experienced high level of stress at (OR = 0.32, 95% CI = 0.14-0.77).

CONCLUSION

Identifying mothers with high level of stressors as well as children with externalizing behaviour problems to provide guidance and support is very important as these two factors appear to be associated with future study performance in both lower and upper secondary school.

School grades and educational attainments of adolescents and young adults born preterm

Attendance in special education (SE) is more common among individuals born preterm than among those born at term. Less is known about school grades of those born preterm in mainstream education (ME), and how these grades predict later educational attainment. This population-based register-linkage study assessed (1) attendance in SE, and then focused on those in ME by assessing (2) school grades at 16 year, (3) completed educational level at 25 year, and (4) school grades as predictors for completed education by gestational age (GA) with full-term birth (39-41 completed weeks) as reference. The sample comprised 223,744 individuals (10,521 preterm, 4.7%) born in Finland (1/1987-9/1990). Of the sample, 4.9% attended SE. Those born preterm had up to 5.5-fold rates for SE. In ME, those born extremely preterm (EPT) had marginally lower mathematics grades compared with full-term counterparts, whilst those born late preterm or early term had slightly higher grades. Those born EPT or very preterm had lower physical education grades in ME. However, the minor differences in school grades according to GA appear not to translate into educational differences in young adulthood. The associations between school grades at 16 year and completed education at 25 year did not vary by GA.

Data integration of National Dose Registry and survey data using multivariate imputation by chained equations

Introduction

Data integration is the process of merging information from multiple datasets generated from different sources, which can obtain more information in comparison to to one data source. All diagnostic medical radiation workers were enrolled in National Dose Registry (NDR) from 1996 to 2011, linked with mortality and cancer registry data. (https://kdca.go.kr/) Survey was conducted during 2012-2013 using self-reported questionnaire on occupational radiation practices among diagnostic medical radiation workers.

Methods

Data integration of NDR and Survey was performed using the multivariate imputation by chained equations (MICE) algorithm.

Results

The results were compared by sex and type of job because characteristics of target variables for imputation depend on these variables. There was a difference between the observed and pooled mean for the frequency of interventional therapy for nurses due to different type of medical facility distribution between observed and completed data. Concerning the marital status of males and females, and status of pregnancy for females, there was a difference between observed and pooled mean because the distribution of the year of birth was different between the observed and completed data. For lifetime status of smoking, the percentage of smoking experience was higher in the completed data than in the observed data, which could be due to reasons, such as underreporting among females and the distribution difference in the frequency of drinking between the observed and completed data for males.

Conclusion

Data integration can allow us to obtain survey information of NDR units without additional surveys, saving us time and costs for the survey.

Neurodevelopment at two years and appropriate schooling at five years in children born very preterm

AIM

This single-centre French cohort study evaluated the relationship between standardised assessment at 2 years of corrected age and schooling level at 5 years of age in children born at ≤32 weeks' gestational age.

METHODS

This was a single-centre retrospective study of children born preterm between 2010 and 2014 included in a follow-up network. At 5 years of age, the population was divided into 2 groups: (1) 'appropriate schooling', defined as age-appropriate schooling without support, and (2) 'schooling with support'. At 2 years of corrected age, the developmental quotient (DQ) was calculated using the revised Brunet-Lezine test. Neonatal variables and DQ categories were compared between the 2 groups on univariate and multivariate analyses.

RESULTS

DQ was available for 251 of the 270 children included (93%), with a median score of 93.0 (IQR [87.0-100.0]), and 171 children (68%) were in the schooling without support group. On multivariate analysis, DQ ≥100 (n = 67) was the only variable that significantly associated with schooling without support (OR = 13.9; 95% CI: 5.5-35.4) at 5 years of age.

CONCLUSION

This result may be useful for clinicians in their routine practice and for information given to parents in neonatal follow-up.

Education Outcomes of Children Born Late Preterm: A Retrospective Whole-Population Cohort Study

BACKGROUND

Early life exposures can have an impact on a child's developmental trajectory and children born late preterm (34-36 weeks gestational age) are increasingly recognized to have health and developmental setbacks that extend into childhood.

OBJECTIVES

The purpose of this study was to assess whether late preterm birth was associated with poorer developmental and educational outcomes in the early childhood period, after controlling for health and social factors.

METHODS

We conducted a retrospective cohort study using administrative databases housed at the Manitoba Centre for Health Policy, including all children born late preterm (34-36 weeks gestational age (GA)) and at full-term (39-41 weeks GA) between 2000 and 2005 in urban Manitoba (N = 28,100). Logistic regression was used to examine the association between gestational age (GA) and outcomes, after adjusting for covariates.

RESULTS

Adjusted analyses demonstrated that children born late preterm had a higher prevalence of attention deficit hyperactivity disorder (ADHD) (aOR = 1.25, 95% CI [1.03, 1.51]), were more likely to be vulnerable in the language and cognitive (aOR = 1.29, 95% CI [1.06, 1.57]), communication and general knowledge (aOR = 1.24, 95% CI [1.01, 1.53]), and physical health and well-being (aOR = 1.27, 95% CI [1.04, 1.53]) domains of development at kindergarten, and were more likely to repeat kindergarten or grade 1 (aOR = 1.52, 95% CI [1.03, 2.25]) compared to children born at term. They did not differ in receipt of special education funding, in social maturity or emotional development at kindergarten, and in reading and numeracy assessments in the third grade.

CONCLUSIONS

Given that the late preterm population makes up 75% of the preterm population, their poorer outcomes have implications at the population level. This study underscores the importance of recognizing the developmental vulnerability of this population and adequately accounting for the social differences between children born late preterm and at term.

Gestational age at term delivery and children's neurocognitive development

BACKGROUND

Preterm birth is associated with lower neurocognitive performance. However, whether children's neurodevelopment improves with longer gestations within the full-term range (37-41 weeks) is unclear. Given the high rate of obstetric intervention in the USA, it is critical to determine whether long-term outcomes differ for children delivered at each week of term.

METHODS

This secondary analysis included 39 199 live-born singleton children of women who were admitted to the hospital in spontaneous labour from the US Collaborative Perinatal Project (1959-76). At each week of term gestation, we evaluated development at 8 months using the Bayley Scales of Infant Development, 4 years using the Stanford-Binet IQ (SBIQ) domains and 7 years using the Wechsler Intelligence Scales for Children (WISC) and Wide-Range Achievement Tests (WRAT).

RESULTS

Children's neurocognitive performance improved with each week of gestation from 37 weeks, peaking at 40 or 41 weeks. Relative to those delivered at 40 weeks, children had lower neurocognitive scores at 37 and 38 weeks for all assessments except SBIQ and WISC Performance IQ. Children delivered at 39 weeks had lower Bayley Mental (β = -1.18; confidence interval -1.77, -0.58) and Psychomotor (β = -1.18; confidence interval -1.90, -0.46) scores. Results were similar for within-family analyses comparing siblings, with the addition of lower WRAT scores at 39 weeks.

CONCLUSIONS

The improvement in development scores across assessment periods indicates that each week up to 40 or 41 weeks of gestation is important for short- and long-term cognitive development, suggesting 40-41 weeks may be the ideal delivery window for optimal neurodevelopmental outcomes.

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.

Consumption of a Low Carbohydrate Diet in Overweight or Obese Pregnant Women Is Associated with Longer Gestation of Pregnancy

Studies of obstetric outcomes in women consuming low-carbohydrate diets have reported conflicting results. Most studies have defined low-carbohydrate diets by the percentage that carbohydrates contribute to overall energy intake, rather than by an absolute amount in grams per day (g/d). We hypothesised that a low absolute carbohydrate diet affects obstetric outcomes differently than a low percentage carbohydrate diet. Dietary data were collected from overweight or obese women in the Study of Probiotic IN Gestational diabetes at 16- and 28-weeks' gestation. Obstetric outcomes were compared between women whose carbohydrate intake was in the lowest quintile vs quintiles 2-5. Mean gestation was increased in women whose absolute carbohydrate intake was in the lowest quintile at 16 and at both 16- and 28-weeks' gestation compared with all other women (16: 39.7 vs. 39.1 weeks, p = 0.008; 16 and 28: 39.8 vs. 39.1, p = 0.005). In linear regression analysis, a low absolute carbohydrate intake at 16 and at 28 weeks' gestation was associated with increased gestation at delivery (16: p = 0.04, adjusted R2 = 0.15, 28: p = 0.04, adjusted R2 = 0.17). The coefficient of beta at 16 weeks' gestation was 0.50 (95% CI 0.03-0.98) and at 28 weeks' gestation was 0.51 (95%CI 0.03-0.99) meaning that consumption of a low absolute carbohydrate diet accounted for an extra 3.5 days in gestational age. This finding was not seen in women whose percentage carbohydrate intake was in the lowest quintile. Low-carbohydrate consumption in pregnancy is associated with increased gestational age at delivery.

School performance in children born after ICSI

STUDY QUESTION

Do children conceived after ICSI have similar school performance as children born after IVF?

SUMMARY ANSWER

Children born after ICSI have similar school performance compared to children born after IVF.

WHAT IS KNOWN ALREADY

Studies concerning the cognitive skills of children born after ICSI have shown diverging results.

STUDY DESIGN, SIZE, DURATION

This nationwide, register-based cohort study included all singleton children born after ICSI (n = 6953), IVF (n = 11 713) or spontaneous conception (SC) (n = 2 022 995), in Sweden between 1985 and 2006.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Singleton children born after ICSI were identified in national IVF registers, cross-linked with the Medical Birth Register (MBR), the National Patient Register (NPR) and the Swedish Cause of Death Register (CDR) for characteristics and medical outcomes. Data on school performance, parental education and other parental characteristics were obtained through cross-linking to the National School Registry and to Statistics Sweden. The main control group, which consisted of children born after IVF, was identified in the national IVF registries while the second control group, consisting of children born after SC, was identified from the MBR. Simple and multivariable linear regression was used for analysis of continuous variables, and logistic regression was used for the analysis of binary outcomes. Adjustments were made for sex, year of birth, maternal smoking during pregnancy, parental age, parity, parental region of birth, parental level of education and frozen embryo transfer.

MAIN RESULTS AND THE ROLE OF CHANCE

In the adjusted analyses, there was no significant difference between ICSI and IVF children for total score (adjusted odds ratios (AORs) 1.03; 95% CI −0.22 to 2.28; P = 0.11), specific subjects, qualifying for secondary school (AOR 1.02; 95% CI 0.82–1.26; P = 0.87) or poor school performance (AOR 0.92; 95% CI 0.75−1.14; P = 0.47). In the third grade, children born after ICSI had a significantly lower chance of passing all of the subtests in Mathematics (AOR 0.89; 0.83–0.96; P = 0.002) and Swedish (AOR 0.92; 0.85–0.99; P = 0.02) compared to children born after SC. When cross-linking children with missing data on school performances (2.1% for ICSI, 2.0% for IVF and 2.3% for SC) with the Cerebral Palsy Follow-up Register (CPUP) for cerebral palsy, 2.7% of ICSI children, 5.7% of IVF children and 1.7% of SC children without registered education were found. When cross-linking children with missing data on school performances with the NPR for mental retardation, 29.9% of ICSI children, 32.6% of IVF children and 35.0% of SC children with missing data were registered under such a diagnosis.

LIMITATIONS, REASONS FOR CAUTION

The main limitation was that test scores were missing in a small percentage in both ICSI and IVF children. Although we were able to cross-link this subpopulation with the CPUP and the NPR, these diagnoses only partly explained the missing scores. Other limitations were unmeasured and unknown possible confounders, such as information about infertility diagnoses and indication for ICSI, were not available.

WIDER IMPLICATIONS OF THE FINDINGS

These findings are important to most countries where IVF and ICSI are used since there may be differences in choice of procedure. In recent years, there has been an increasing trend towards using ICSI not only for treatment of male infertility but also when the sperm quality is normal. Our results indicate that the school performance of children born after ICSI is reassuring.

STUDY FUNDING/COMPETING INTEREST(S)

Financial support was received through Sahlgrenska University Hospital (ALFGBG – 70 940), Hjalmar Svensson Research Foundation and Nordforsk, project number 71 450. None of the authors declare any conflict of interest.

TRIAL REGISTRATION NUMBER

N/A

Very preterm infants engage in an intervention to train their control of attention: results from the feasibility study of the Attention Control Training (ACT) randomised trial

Background

Very premature birth (gestational age between 28 and 31 + 6 weeks) is associated with increased risk of cognitive delay and attention deficit disorder, which have been linked to anomalies in the development of executive functions (EFs) and their precursors. In particular, very preterm (VP) infants display anomalies in controlling attention and gathering task-relevant information. Early interventions that support attention control may be pivotal in providing a secure base for VP children’s later attainments. The Attention Control Training (ACT) is a cognitive training intervention that targets infants’ abilities to select visual information according to varying task demands but had not been tested in VP infants. We conducted a feasibility study to test the processes we intend to use in a trial delivering the ACT to VP infants.

Methods and design

We tested recruitment and retention of VP infants and their families in a randomised trial, as well as acceptability and completion of baseline and outcome measures. To evaluate these aims, we used descriptive quantitative statistics and qualitative methods to analyse feedback from infants’ caregivers. We also investigated the quality of eye-tracking data collected and indicators of infants’ engagement in the training, using descriptive statistics.

Results

Twelve VP infants were recruited, and 10 (83%) completed the study. Participants’ parents had high education attainment. The rate of completion of baseline and outcome measures was optimal. VP infants demonstrated engagement in the training, completing on average 84 min of training over three visits, and displaying improved performance during this training. Eye-tracking data quality was moderate, but this did not interfere with infants’ engagement in the training.

Discussion

The results suggest the ACT can be delivered to VP infants. However, challenges remain in recruitment of numerous and diverse samples. We discuss strategies to overcome these challenges informed by results of this study.

Trial registration

Registered Registration ID: NCT03896490. Retrospectively registered at Clinical Trials Protocol Registration and Results System (clinicaltrials.gov).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40814-021-00809-z.

The influence of breastfeeding and pacifier use on the association between preterm birth and primary-dentition malocclusion: A population-based birth cohort study

INTRODUCTION

Little is known about the influence of biological characteristics on the occurrence of malocclusion. This study aimed to investigate the association between preterm birth and primary-dentition malocclusion and how breastfeeding and the use of pacifiers are related to this association.

METHODS

A representative sample (n = 1129) of children from the 2004 Pelotas, Brazil birth cohort study underwent a dental examination at age 5 years. Malocclusions were diagnosed according to the World Health Organization criteria, and the outcome was considered as the presence of moderate or severe malocclusion (MSM). Questionnaires including the children's oral health information were completed by the mothers. Data on socioeconomic status, breastfeeding, and preterm birth were obtained from previous follow-ups. Poisson regression analysis was conducted, followed by an interaction test.

RESULTS

The prevalence of MSM was 26.3% (95% confidence interval [CI], 23.6%-29.1%) in the total sample, 24.1% (95% CI, 21.5%-26.9%) in full-term births, and 42.2% (95% CI, 39.1%-45.3%) in preterm births. After adjustment, the prevalence of MSM was 42% higher in preterm births. Breastfeeding duration and pacifier use up to age 4 years modified the effect of gestational age on MSM.

CONCLUSIONS

Preterm birth is associated with the development of MSM. Breastfeeding reduces the effect of preterm birth on MSM, and pacifier use strengthens this association. Dentists should be aware that preterm birth may be a risk factor for malocclusion in primary dentition. The findings reinforce the benefits of breastfeeding on occlusal development and the negative consequences of pacifier use.

Poor academic performance in offspring of survivors with childhood or adolescent central nervous system tumor in Sweden

The number of children who were born after their parents were diagnosed with central nervous system (CNS) tumor is increasing, but it remains largely unknown regarding the academic performance of these children. We aimed to investigate whether children of survivors with childhood or adolescent CNS tumor were associated with poor academic performance. Children of survivors of CNS tumor were identified by combining the nationwide Swedish Cancer Register and the Multi-Generation Register, and those who have completed compulsory education in Sweden between 1989 and 2015 were included in our study. "Poor academic performance" was defined as a z-score of the academic performance below the 10th percentile. Conditional logistic regression and quantile regression were used to examine the association. A total of 655 children were born after their parental diagnosis of CNS tumor and they had 1.39 times higher risk of achieving poor academic performance as compared to the matched comparisons (95% CI = 1.10-1.76). The poor academic performance was even more pronounced in boys, among those with a paternal diagnosis of CNS tumor and those with a parental ependymoma. The observed association differed depending on preterm birth. In addition, the strength of the association declined with the increased quantiles of academic performance z-score. Our data suggest that parental CNS tumor affects the subsequent academic achievements among children born after the parental tumor.

Training attention control of very preterm infants: protocol for a feasibility study of the Attention Control Training (ACT)

BACKGROUND

Children born preterm may display cognitive, learning, and behaviour difficulties as they grow up. In particular, very premature birth (gestation age between 28 and less than 32 weeks) may put infants at increased risk of intellectual deficits and attention deficit disorder. Evidence suggests that the basis of these problems may lie in difficulties in the development of executive functions. One of the earliest executive functions to emerge around 1 year of age is the ability to control attention. An eye-tracking-based cognitive training programme to support this emerging ability, the Attention Control Training (ACT), has been developed and tested with typically developing infants. The aim of this study is to investigate the feasibility of using the ACT with healthy very preterm (VP) infants when they are 12 months of age (corrected age). The ACT has the potential to address the need for supporting emerging cognitive abilities of VP infants with an early intervention, which may capitalise on infants' neural plasticity.

METHODS/DESIGN

The feasibility study is designed to investigate whether it is possible to recruit and retain VP infants and their families in a randomised trial that compares attention and social attention of trained infants against those that are exposed to a control procedure. Feasibility issues include the referral/recruitment pathway, attendance, and engagement with testing and training sessions, completion of tasks, retention in the study, acceptability of outcome measures, quality of data collected (particularly, eye-tracking data). The results of the study will inform the development of a larger randomised trial.

DISCUSSION

Several lines of evidence emphasise the need to support emerging cognitive and learning abilities of preterm infants using early interventions. However, early interventions with preterm infants, and particularly very preterm ones, face difficulties in recruiting and retaining participants. These problems are also augmented by the health vulnerability of this population. This feasibility study will provide the basis for informing the implementation of an early cognitive intervention for very preterm infants.

TRIAL REGISTRATION

Registered Registration ID: NCT03896490. Retrospectively registered at Clinical Trials Protocol Registration and Results System (clinicaltrials.gov).

School performance and long-term outcomes of very preterm children conceived via in vitro fertilization

Objective

To assess the impact of in vitro fertilization (IVF) on school performance and long-term outcomes in very preterm children aged 8-16 years.

Methods

Seventy-nine children born after IVF were compared with 79 randomly selected matched controls born after spontaneous conception (SC). Information was obtained from parents via a questionnaire administered through telephone interviews looking into school performance, including preschool education, repeated grades, extra lessons, special education needs, and learning difficulties; long-term status, including incidence of attention deficit hyperactivity disorder and autism; and family profile. Gross motor function was assessed against the gross motor function classification system based on information given by the subjects' families.

Results

Mothers of IVF children were more likely to have a high educational level than mothers of SC children. Moreover, a greater proportion of IVF children had received preschool education than SC children. After adjusting for potential confounders, there was no difference in the school performance or long-term outcomes between IVF and SC children.

Conclusion

In our study, the school performance and long-term outcomes of very preterm children born after IVF and of their spontaneously conceived peers were comparable. This information can help provide guidance to families and educators.

Cohort profile: the Neonatal Intensive Care Unit Hospital Exposures and Long-Term Health (NICU-HEALTH) cohort, a prospective preterm birth cohort in New York City

PURPOSE

The Neonatal Intensive Care Unit Hospital Exposures and Long-Term Health (NICU-HEALTH) longitudinal preterm birth cohort studies the impact of the NICU exposome on early-life development. NICU-HEALTH collects multiple biospecimens, complex observational and survey data and comprehensive multisystem outcome assessments to allow measurement of the impact of modifiable environmental exposures during the preterm period on neurodevelopmental, pulmonary and growth outcomes.

PARTICIPANTS

Moderately preterm infants without genetic or congenital anomalies and their mothers are recruited from an urban academic medical centre level IV NICU in New York City, New York, USA. Recruitment began in 2011 and continues through multiple enrolment phases to the present with goal enrolment of 400 infants. Follow-up includes daily data collection throughout the NICU stay and six follow-up visits in the first 2 years. Study retention is 77% to date, with the oldest patients turning age 8 in 2019.

FINDINGS TO DATE

NICU-HEALTH has already contributed significantly to our understanding of phthalate exposure in the NICU. Phase I produced the first evidence of the clinical impact of phthalate exposure in the NICU population. Further study identified specific sources of exposure to clinically relevant phthalate mixtures in the NICU.

FUTURE PLANS

Follow-up from age 3 to 12 is co-ordinated through integration with the Environmental Influences on Child Health Outcomes (ECHO) programme. The NICU-HEALTH cohort will generate a wealth of biomarker, clinical and outcome data from which future studies of the impact of early-life chemical and non-chemical environmental exposures can benefit. Findings from study of this cohort and other collaborating environmental health cohorts will likely translate into improvements in the hospital environment for infant development.

TRIAL REGISTRATION NUMBERS

This observational cohort is registered with ClinicalTrials.gov (NCT01420029 and NCT01963065).

Investigating the association between post-term birth and long term cognitive, developmental and educational impacts: a systematic review and Meta-analysis

Purpose: Infants who remain in-utero after their due date are exposed to increasing risk of infection, late stillbirth and delivery complications. Much of the current literature on post-term outcomes is based on short term observations and the impacts may be substantially greater in the long term. The aim of this work is to perform a systematic review and meta-analysis to quantify the cognitive or educational impacts of post term delivery.Methods: Systematic review was performed by the two authors using Medline database (1960-2017). A title search was performed to identify likely relevant literature. Exposure terms were clarified to identify papers where the exposure was related to delivery after the infants' due date. Primary outcome was cognitive score. A quality assessment and data extraction pro forma was completed by both reviewers for all studies deemed to satisfy the inclusion and exclusion criteria. Meta-analysis used adjusted results where available. Small-study bias was assessed visually using a funnel plot and then formally tested using Egger's regression asymmetry test.Results: Medline was searched on the 4 July 2018; and produced a list of 1318 publications. Of these, 43 abstracts were screened, and of these a total of 10 full-text papers were reviewed. A further three papers were identified during this review and contributed to a total of 13 papers. The publications dated from 1969 to 2017. Two studies presented a binary outcome for cognitive measures and combined estimates found that the risk of a low cognitive score was higher in post-term infants compared to term infants (odds ratio [OR] 1.06 [1.04-1.08]). Four papers presented the association with mean cognitive measures and post-term delivery, and all demonstrated a mean reduction in scores in the post-term group. A combined estimate showed strong evidence of a reduction in cognitive scores across the four studies (-1.90 [-3.50 to -0.31]). There was little evidence of heterogeneity in the studies which reported cognitive outcomes (other p-values >.2).Conclusion: This meta-analysis has found that post term birth (>41 + 6 weeks) is associated with small but significant negative effects on cognitive outcomes when compared with delivery at, or around term. The effect, while small, is compounded by a common exposure and appears consistent in the studies identified. Less evidence was found for a measurable impact on early developmental measures or educational outcomes. This may further help inform the debate on the timing of otherwise uncomplicated pregnancies and further trials in this area.

Chinese handwriting performance in preterm children in grade 2

Background

First graders born prematurely perform poorly on handwriting speed and legibility. However, whether there are specific legibility factors in which preterm children demonstrate difficulty remains unknown. In addition, handwriting performance beyond the first grade and the influence of sex on handwriting performance in preterm children are still unclear. We aimed to investigate the influence of prematurity and sex on multiple dimensions of handwriting in grade two and to identify the contributors to performance.

Methods

Sixty-three preterm (34 boys and 29 girls) and 67 full-term (27 boys and 40 girls) peers in grade two were included. Class teachers were asked to complete the Chinese Handwriting Evaluation Form. A subgroup of 39 preterm children received assessments on intelligence, visual perception, tactile and kinesthetic sensation, and fine motor skills. Their inattention behavior was rated using a maternal self-report with a behavioral scale.

Results

Boys born prematurely exhibited poorer performance in the speed dimension than full-term boys (p = 0.008), whereas there was comparable performance in the two groups of girls (p = 0.221). In the dimensions related to legibility, preterm boys (32.4%) had a higher percentage of children with difficulty in the construction dimension than the other groups (preterm girls: 6.9%, full-term boys: 7.4%, full-term girls: 5.0%). However, no group difference was found in the dimensions of accuracy and directionality. Of the sensory-perceptual-motor factors, attention was the most significant predictor of accuracy in performance (p = 0.046) and speed dimensions (p = 0.001) in preterm children.

Conclusions

Boys appear to be vulnerable to the adverse impacts of preterm birth in terms of performance in the dimensions of speed and construction in grade two. Based on the significant contribution of attention to handwriting performance in preterm children, assessment and intervention in the area of attention is strongly suggested for preterm children with handwriting problems.

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.

Neonatal intensive care unit phthalate exposure and preterm infant neurobehavioral performance

Every year in the United States, more than 300,000 infants are admitted to neonatal intensive care units (NICU) where they are exposed to a chemical-intensive hospital environment during a developmentally vulnerable period. The neurodevelopmental impact of environmental exposure to phthalates during the NICU stay is unknown. As phthalate exposure during the third trimester developmental window has been implicated in neurobehavioral deficits in term-born children that are strikingly similar to a phenotype of neurobehavioral morbidity common among children born premature, the role of early-life phthalate exposure on the neurodevelopmental trajectory of premature infants may be clinically important. In this study, premature newborns with birth weight <1500g were recruited to participate in a prospective environmental health cohort study, NICU-HEALTH (Hospital Exposures and Long-Term Health), part of the DINE (Developmental Impact of NICU Exposures) cohort of the ECHO (Environmental influences on Child Health Outcomes) program. Seventy-six percent of eligible infants enrolled in the study. Sixty-four of 81 infants survived and are included in this analysis. 164 urine specimens were analyzed for phthalate metabolites using high-performance liquid chromatography/tandem mass spectrometry. The NICU Network Neurobehavioral Scale (NNNS) was performed prior to NICU discharge. Linear and weighted quantile sum regression quantified associations between phthalate biomarkers and NNNS performance, and between phthalate biomarkers and intensity of medical intervention. The sum of di(2-ethylhexyl) phthalate metabolites (∑DEHP) was associated with improved performance on the Attention and Regulation scales. Specific mixtures of phthalate biomarkers were also associated with improved NNNS performance. More intense medical intervention was associated with higher ∑DEHP exposure. NICU-based exposure to phthalates mixtures was associated with improved attention and social response. This suggests that the impact of phthalate exposure on neurodevelopment may follow a non-linear trajectory, perhaps accelerating the development of certain neural networks. The long-term neurodevelopmental impact of NICU-based phthalate exposure needs to be evaluated.

Premature Adult Death in Individuals Born Preterm: A Sibling Comparison in a Prospective Nationwide Follow-Up Study

Background

Close to one in ten individuals worldwide is born preterm, and it is important to understand patterns of long-term health and mortality in this group. This study assesses the relationship between gestational age at birth and early adult mortality both in a nationwide population and within sibships. The study adds to existing knowledge by addressing selected causes of death and by assessing the role of genetic and environmental factors shared by siblings.

Methods

Study population was all Norwegian men and women born from 1967 to 1997 followed using nation-wide registry linkage for mortality through 2011 when they were between 15 and 45 years of age. Analyses were performed within maternal sibships to reduce variation in unobserved genetic and environmental factors shared by siblings. Specific outcomes were all-cause mortality and mortality from cardiovascular diseases, cancer and external causes including accidents, suicides and drug abuse/overdoses.

Results

Compared with a sibling born in week 37–41, preterm siblings born before 34 weeks gestation had 50% increased mortality from all causes (adjusted Hazard Ratio (aHR) 1.54, 95% confidence interval (CI) 1.17, 2.03). The corresponding estimate for the entire population was 1.27 (95% CI 1.09, 1.47). The majority of deaths (65%) were from external causes and the corresponding risk estimates for these deaths were 1.52 (95% CI 1.08, 2.14) in the sibships and 1.20 (95% CI 1.01, 1.43) in the population.

Conclusion

Preterm birth before week 34 was associated with increased mortality between 15 and 45 years of age. The results suggest that increased premature adult mortality in this group is related to external causes of death and that the increased risks are unlikely to be explained by factors shared by siblings.

The phenotype of spontaneous preterm birth: application of a clinical phenotyping tool

OBJECTIVE

Spontaneous preterm birth (SPTB) is a complex condition that is likely a final common pathway with multiple possible causes. We hypothesized that a comprehensive classification system appropriately could group women with similar STPB causes and could provide an explanation, at least in part, for the disparities in SPTB that are associated with race and gestational age at delivery.

STUDY DESIGN

This was a planned analysis of a multicenter, prospective study of singleton SPTBs. Women with SPTB at <34 weeks' gestation were included. We defined 9 potential SPTB phenotypes based on clinical data: infection/inflammation, maternal stress, decidual hemorrhage, uterine distention, cervical insufficiency, placental dysfunction, premature rupture of the membranes, maternal comorbidities, and familial factors. Each woman's condition was evaluated for each phenotype. Delivery gestational age was compared between those with and without each phenotype. Phenotype profiles were also compared between women with very early (20.0-27.9 weeks' gestation) SPTB vs those with early SPTB (28.0-34.0 weeks' gestation) and between African American and white women. Statistical analysis was by t test and χ(2) test, as appropriate.

RESULTS

The phenotyping tool was applied to 1025 women with SPTBs who delivered at a mean 30.0 ± 3.2 (SD) weeks' gestation. Of these, 800 women (78%) had ≥2 phenotypes. Only 43 women (4.2%) had no phenotypes. The 281 women with early SPTBs were more likely to have infection/inflammation, decidual hemorrhage, and cervical insufficiency phenotypes (all P ≤ .001). African American women had more maternal stress and cervical insufficiency but less decidual hemorrhage and placental dysfunction compared with white women (all P < .05). Gestational age at delivery decreased as the number of phenotypes that were present increased.

CONCLUSION

Precise SPTB phenotyping classifies women with SPTBs and identifies specific differences between very early and early SPTB and between African American and white women.