Post-term Birth and Developmental Coordination Disorder: A Narrative Review of Motor Impairments in Children

A prevalent long-term medical condition in children that is rarely understood and acknowledged in educational contexts is developmental coordination disorder (DCD), which is one of the most prevalent conditions in school-aged children. Mild-to-severe abnormalities in muscle tone, posture, movement, and the learning of motor skills are associated with motor disorders. Early detection of developmental abnormalities in children is crucial as delayed motor milestones during infancy might indicate a delay in both physical and neurological development. To overcome the current condition of motor impairment, obstructing their risk factors is important to prevent the development of disability, which is already determined in the prenatal and perinatal period. Concerning the relationship with gestational age, the majority of the studies reported a relationship between DCD and preterm children. However, the entire range of gestational age, including post-term birth, has not been studied. The risk of developmental consequences such as cognitive impairments, major mental diseases, attention-deficit/hyperactivity disorder, autism spectrum disorder, and other behavioral and emotional problems increases in post-term birth, according to prior studies. Thus, this review aims to provide an overview of information linking post-term birth to children's motor impairment, with a focus on DCD. A thorough systemic review was conducted on online databases, and only a few studies were found on the association with post-term children. Insufficient evidence made it necessary to examine more post-term cohorts in adolescence to fully determine the long-term health concerns and develop therapies to mitigate the detrimental effects of post-term deliveries.

Reducing behavior problems in children born after an unintended pregnancy: the generation R study

OBJECTIVES

To examine differences in behavior problems between children from intended versus unintended pregnancies, and to estimate how much the difference in problem behavior would be reduced if postnatal depression was eliminated and social support was increased within 6 months after birth.

METHODS

Data from the Generation R Study were used, a population-based birth cohort in Rotterdam, the Netherlands (N = 9621). Differences in child internalizing and externalizing behavior at ages 1.5, 3, 6, 9 and 13 years between pregnancy intention groups were estimated using linear regression. Associations of postnatal depression and social support with internalizing and externalizing problems were also estimated using linear regression. Child behavior outcomes where compared before and after modelling a situation in which none of the mothers experienced a postnatal depression and all mother experienced high social support.

RESULTS

Most pregnancies (72.9%) were planned, 14.8% were unplanned and wanted, 10.8% were unplanned with initially ambivalent feelings and 1.5% with prolonged ambivalent feelings. Children from unplanned pregnancies had more internalizing and externalizing problems at all ages as compared to children from a planned pregnancy, especially when ambivalent feelings were present. Hypothetically eliminating on postnatal depression reduced the differences in internalizing and externalizing problems by 0.02 to 0.16 standard deviation. Hypothetically increasing social support did not significantly reduce the difference in internalizing and externalizing problems.

CONCLUSIONS

Children from an unplanned pregnancy have more behavior problems, in particular when mothers had prolonged ambivalent feelings. Eliminating postnatal depression may help to reduce the inequality in child behavior related to pregnancy intention.

Associations between gestational weight gain under different guidelines and adverse birth outcomes: A secondary analysis of a randomized controlled trial in rural western China

Several gestational weight gain (GWG) guidelines have been established based on monocenter or multicenter researches. We aimed to examine the associations between categories of GWG under the Institute of Medicine (IOM) recommendation guideline, the Chinese National Health Commission (NHC) guideline, and weight-gain-for-gestational-age z-scores derived from the INTERGROWTH-21st Project and adverse birth outcomes. We used data from an antenatal micronutrient supplementation trial in rural western China between 2002 and 2006. Maternal weekly average GWG during the second and third trimesters was calculated and classified into inadequate, adequate and excessive GWG according to the IOM and NHC, respectively. Weight-gain-for-gestational-age z-scores derived from the INTERGROWTH-21st Project were grouped into three subgroups using two approaches: z-score percentile<25th, 25th to 75th, >75th and z-score <-1, -1 to 1, >1 SD. Infant birth weight and gestational age were measured using standard approaches. Generalized linear model with binomial family and logit link was applied to estimate the odds ratio (OR) and 95% confidential intervals (CI) for GWG categories and adverse birth outcomes. Among 1,239 women with normal weight (18.5 kg/m2 to 23.9 kg/m2) during early pregnancy, 18.0% and 34.2% were classified as adequate GWG according to IOM and NHC, respectively. Less than half of Chinese women reached optimal GWG by any recommendation guideline. According to NHC, excessive GWG showed a significant association with macrosomia (OR 3.75, 95% CI 1.03, 13.74), large-for-gestation-age (LGA) (OR 2.12, 95% CI 1.01, 4.45), and inadequate GWG was associated with post-term birth (OR 2.25, 95% CI 1.21, 4.16), compared with adequate GWG. Inappropriate GWG was associated with adverse birth outcomes even among women with normal weight during early pregnancy. The monitoring and interventions of weight status during pregnancy, especially for the second and third trimesters, are of great public health importance for optimal birth outcomes. Additionally, developing guideline of appropriate GWG ranges should account for the traits of regional population.

The association between post-term births and autism spectrum disorders: an updated systematic review and meta-analysis

BACKGROUND

This study aimed to conduct a meta-analysis to determine whether post-term birth has an increased risk of ASD.

MATERIALS AND METHODS

To retrieve eligible studies regarding the effect of post-term and ASD in children, major databases including PubMed, Scopus, and Web of Science were searched. A random effect model was used for meta-analysis. For assessing the quality of included studies, the GRADE checklist was used.

RESULTS

In total, 18 records were included with 1,412,667 sample populations from 12 countries. The pooled estimates of RR and OR showed a significant association between post-term birth and ASD among children, respectively (RR = 1.34, 95% CI 1.10 to 1.58) and (OR = 1.47, 95% CI 1.03 to 1.91). There was no heterogeneity among the studies that reported the risk of ASD among children based on RR (I2 = 6.6%, P = 0.301). There was high heterogeneity in the studies reported risk of ASD based on OR (I2 = 94.1%, P = 0.000).

CONCLUSION

Post-term births still occur relatively frequently (up to 5-10%) even in developed countries. Our results showed that post-term birth is an increased risk of ASD, although high heterogeneity was found among the studies reported based on adjusted and crude forms, however, after subgroup analysis by gender, this heterogeneity disappeared among males.

Prenatal and postnatal correlates of moderate-to-vigorous physical activity in midlife: evidence from the 1970 British Cohort Study

Background

It is hypothesised that lifelong physical activity behaviours are established in early life, however there is minimal, and contradictory, evidence examining prenatal and postnatal factors in relation to adulthood physical activity. We investigated associations between prospectively ascertained prenatal/postnatal factors and device-measured moderate-to-vigorous physical activity (MVPA) in midlife.

Methods

Analyses included 5011 participants from the 1970 British Cohort Study, a birth cohort study of individuals born within the same week. At birth, the following factors were ascertained: socioeconomic position (SEP), maternal age, number of previous pregnancies, maternal smoking, maternal diabetes, gestational age, birth weight, breastfeeding status and infant health concerns. MVPA was captured at age 46 with a thigh-worn accelerometer device following a 24-hour protocol over 7 days.

Results

In sex-adjusted models, lower SEP (−6.7 min/day (95% CI: −9.0 to –4.4) in those with a partly or unskilled paternal occupation), younger maternal age (0.4 min/day (0.2 to 0.5) per additional year of maternal age), maternal smoking during pregnancy (−2.5 min/day (−4.0 to –1.0)) and post-term gestational age (−7.4 min/day (−11.5 to –3.4); boys only) were associated with lower MVPA at age 46. In the mutually adjusted model, associations did not change but there was some evidence that birth weight may also be associated with MVPA levels.

Conclusions

SEP, maternal age, maternal smoking, post-term birth in boys and birth weight were associated with MVPA in midlife, indicating that midlife physical activity behaviours may be partially established at birth. Early interventions in disadvantaged environments may have a positive impact on physical activity throughout the life course.

Associations between gestational age and childhood sleep: a national retrospective cohort study

BACKGROUND

Both sleep quality and quantity are essential for normal brain development throughout childhood; however, the association between preterm birth and sleep problems in preschoolers is not yet clear, and the effects of gestational age across the full range from preterm to post-term have not been examined. Our study investigated the sleep outcomes of children born at very-preterm (<31 weeks), moderate-preterm (32-33 weeks), late-preterm (34-36 weeks), early-term (37-38 weeks), full-term (39-40 weeks), late-term (41 weeks) and post-term (>41 weeks).

METHODS

A national retrospective cohort study was conducted with 114,311 children aged 3-5 years old in China. Children's daily sleep hours and pediatric sleep disorders defined by the Children's Sleep Habits Questionnaire (CSHQ) were reported by parents. Linear regressions and logistic regression models were applied to examine gestational age at birth with the sleep outcomes of children.

RESULTS

Compared with full-term children, a significantly higher CSHQ score, and hence worse sleep, was observed in very-preterm (β = 1.827), moderate-preterm (β = 1.409), late-preterm (β = 0.832), early-term (β = 0.233) and post-term (β = 0.831) children, all p<0.001. The association of pediatric sleep disorder (i.e. CSHQ scores>41) was also seen in very-preterm (adjusted odds ratio [AOR] = 1.287 95% confidence interval [CI] (1.157, 1.433)), moderate-preterm (AOR = 1.249 95% CI (1.110, 1.405)), late-preterm (AOR = 1.111 95% CI (1.052, 1.174)) and post-term (AOR = 1.139 95% CI (1.061, 1.222)), all p<0.001. Shorter sleep duration was also found in very-preterm (β = -0.303), moderate-preterm (β = -0.282), late-preterm (β = -0.201), early-term (β = -0.068) and post-term (β = -0.110) compared with full-term children, all p<0.01. Preterm and post-term-born children had different sleep profiles as suggested by subscales of the CSHQ.

CONCLUSIONS

Every degree of premature, early-term and post-term birth, compared to full-term, has an association with sleep disorders and shortened daily sleep duration. Preterm, early-term, and post-term should therefore all be monitored with an increased threat of sleep disorder that requires long-term monitoring for adverse sleep outcomes in preschoolers.

Infant inflammation predicts childhood emotional and behavioral problems and partially mediates socioeconomic disadvantage

BACKGROUND

Emotional and behavioral problems (EBP) are common in children. Environmental factors like socioeconomic disadvantage influence EBP pathogenesis and can trigger inflammation. However, the link between early inflammation-EBP in children is unclear. We investigated the associations between i) infant inflammatory biomarkers and subsequent EBP and ii) early life environmental factors and EBP and assessed whether infant inflammation mediated these associations.

METHODS

Inflammatory biomarkers glycoprotein acetyls (GlycA) and high-sensitivity C-reactive protein (hsCRP) were quantified at birth and 12 months in a population-derived birth cohort, the Barwon Infant Study. Early life factors including demographic, prenatal, and perinatal factors were collected from antenatal to the two-year period. Internalizing and externalizing problems at age two were measured by the Child Behavior Checklist. Prospective associations were examined by multivariable regression analyses adjusted for potential confounders. Indirect effects of early life factors on EBP through inflammation were identified using mediation analyses.

RESULTS

Elevated GlycA levels at birth (GlycAbirth) were associated with greater internalizing problems at age two (β = 1.32 per SD increase in GlycA; P = 0.001). Inflammation at birth had a stronger magnitude of effect with later EBP than at 12 months. GlycAbirth partially mediated the associations between lower household income (6%), multiparity (12%) and greater number of older siblings (13%) and EBP. Patterns were less evident for hsCRP or externalizing problems.

CONCLUSIONS

GlycAbirth was positively associated with EBP at age two and partially mediated the association between several indicators of socioeconomic disadvantage and EBP. Prenatal and perinatal inflammation may be relevant to early neurodevelopment and emotional health.

Engineered models for placental toxicology: Emerging approaches based on tissue decellularization

Recent increases in prescriptions and illegal drug use as well as exposure to environmental contaminants during pregnancy have highlighted the critical importance of placental toxicology in understanding and identifying risks to both mother and fetus. Although advantageous for basic science, current in vitro models often fail to capture the complexity of placental response, likely due to their inability to recreate and monitor aspects of the microenvironment including physical properties, mechanical forces and stiffness, protein composition, cell-cell interactions, soluble and physicochemical factors, and other exogenous cues. Tissue engineering holds great promise in addressing these challenges and provides an avenue to better understand basic biology, effects of toxic compounds and potential therapeutics. The key to success lies in effectively recreating the microenvironment. One strategy to do this would be to recreate individual components and then combine them. However, this becomes challenging due to variables present according to conditions such as tissue location, age, health status and lifestyle. The extracellular matrix (ECM) is known to influence cellular fate by working as a storage of factors. Decellularized ECM (dECM) is a recent tool that allows usage of the original ECM in a refurbished form, providing a relatively reliable representation of the microenvironment. This review focuses on using dECM in modified forms such as whole organs, scaffold sheets, electrospun nanofibers, hydrogels, 3D printing, and combinations as building blocks to recreate aspects of the microenvironment to address general tissue engineering and toxicology challenges, thus illustrating their potential as tools for future placental toxicology studies.

Is limited access to obstetric services associated with adverse birth outcomes? A cross-sectional study of Korean national birth data

OBJECTIVES

The geographical disparity in the access to essential obstetric services is a public health issue in many countries. We explored the association between timely access to obstetric services and the individual risk of adverse birth outcomes.

DESIGN

Repeated cross-sectional design.

SETTING

South Korean national birth data linked with a medical service provision database.

PARTICIPANTS

1 842 718 singleton livebirths from 2014 to 2018.

PRIMARY OUTCOME MEASURES

Preterm birth (PTB), post-term birth, low birth weight (LBW) and macrosomia.

RESULTS

In the study population, 9.3% of mothers lived in districts where the Time Relevance Index (TRI) was as low as the first quartile (40.6%). Overall PTB and post-term birth rates were 5.0% and 0.1%, respectively. Among term livebirths, LBW and macrosomia occurred in 1.0% and 3.3%, respectively. When the TRI is lower, representing less access to obstetric care, the risk of macrosomia was higher (adjusted OR=1.15, 95% CI 1.11 to 1.20 for Q1 compared with Q4). Similarly, PTB is more likely to occur when TRI is lower (1.05, 95% CI 1.00 to 1.10 for Q1; 1.03, 95% CI 1.01 to 1.05 for Q2). There were some inverse associations between TRI and post-term birth (0.80, 95% CI 0.71 to 0.91, for Q2; 0.84, 95% CI 0.76 to 0.93, for Q3).

CONCLUSIONS

We observed less accessibility to obstetric service is associated with higher risks of macrosomia and PTB. This finding supports the role of obstetric service accessibility in the individual risk of adverse birth outcomes.

Association between postterm pregnancy and adverse growth outcomes in preschool-age children

BACKGROUND

Postterm pregnancy has been associated with higher risk of perinatal mortality and morbidity, but its long-term health effects on offspring are poorly understood.

OBJECTIVES

The aim of the study was to investigate the prospective associations between maternal postterm pregnancy and adverse growth outcomes in children.

METHODS

The Jiaxing Birth Cohort is part of a large population-based health surveillance system in China and recruited pregnant females resident in the Jiaxing area between 1999 and 2013; newborns were followed up for a median duration of 5.8 y until they went to school. Mother-child pairs with maternal gestational information and offspring's anthropometric data at 4-7 y old were included. Postterm pregnancy was defined as maternal gestational age ≥42 and <47 wk, and its associations with offspring obesity, overweight/obesity, and thinness during childhood were determined by using Poisson regression models.

RESULTS

Of the 101,505 included mother-child pairs, 2369 (2.3%) children were born at postterm. Children born at postterm had significantly lower BMI-for-age z score, weight-for-age z score, and height-for-age z score than those born at term; the mean difference (95% CI) was -0.11 (-0.15, -0.06), -0.17 (-0.21, -0.13), and -0.16 (-0.20, -0.12), respectively. When comparing postterm with term pregnancy, the multivariable-adjusted RRs and 95% CIs among preschool-age children were 0.87 (0.68, 1.11) for obesity, 0.82 (0.72, 0.94) for overweight/obesity, and 1.18 (1.09, 1.28) for thinness, respectively. These risk estimates were robust in sensitivity analyses, but were attenuated in several subgroups stratified by age, sex, mode of delivery, and fetal distress.

CONCLUSIONS

Postterm pregnancy was associated with a higher risk of thinness, and a lower risk of overweight/obesity, as well as lower growth parameters in preschool-age children. These findings imply that postterm pregnancy may impede the long-term growth of offspring.

Perinatal and birth correlates of childhood irritability in Taiwan's national epidemiological study

BACKGROUND

Childhood irritability, characterized by low frustration tolerance and developmentally-inappropriate temper outbursts, is a transdiagnostic symptom in child psychiatry. Little is known regarding the influences of early experience and environmental exposure on irritability from a perinatal perspective. This study examined the associations between irritability and multiple perinatal and birth factors.

METHODS

Drawn Taiwan's National Epidemiological Study of Child Mental Disorders, 5124 children (2591 females) aged 7.7 to 14.6 years (mean 11.2 years) and their parents completed the Affective Reactivity Index, a well-established irritability measure. Parents completed a survey on parental, perinatal, and birth characteristics. Multiple linear regression models were performed to examine the associations between perinatal and birth characteristics and child irritability reported across informants.

RESULTS

Maternal smoking, vaginal bleeding, and pre-eclampsia during pregnancy and phototherapy for jaundice >3 days were associated with high irritability after adjusting for child's age, sex, and parental characteristics. Findings were consistent across parent- and child-rated irritability.

LIMITATIONS

Retrospective assessment of early exposures may be subject to recall bias despite previously-established validity and reliability. Longitudinal research with prospective assessments of early life exposures is recommended to confirm our findings. This exploratory approach of multiple survey items also precludes more in-depth assessments of perinatal risks for developing irritability.

CONCLUSIONS

This study provides novel evidence suggesting a perinatal link with irritability in a national sample of youths. Given that irritability predicts adverse mental health and life outcomes, identifying its perinatal and birth predictors may inform early etiology, guiding timely assessment and intervention.

Gestational Age in Autistic Children and Adolescents: Prevalence and Effects on Autism Phenotype

Pre- and post-term children show increased autism risk. Little is known about gestational age (GA) prevalence among autistic children, and their respective autism phenotype. We compared prevalence of pre-, full- and post-term birth between a population-derived sample of N = 606 (137 females, 22.61%) autistic children and adolescents (mean age = 14.01, SD = 3.63, range 3–24) from the Netherlands Autism Register, and matched controls from the Dutch birth register. Autism phenotype and comorbid symptoms were assessed with the AQ-short and SDQ questionnaires. Using logistic regression, we found higher prevalence of pre- and post-term birth among autistic individuals but no phenotypical differences across GA groups. Autism risk was particularly elevated for post-term children, highlighting the need for closer investigation of autism on the whole GA range.

Association of Gestational Age at Birth With Subsequent Neurodevelopment in Early Childhood: A National Retrospective Cohort Study in China

BACKGROUND

The association between preterm birth and neurodevelopmental delays have been well examined, however, reliable estimates for the full range of gestational age (GA) are limited, and few studies explored the impact of post-term birth on child development.

OBJECTIVE

This study aimed to examine the long-term neuropsychological outcomes of children born in a full range of GA with a national representative sample in China.

METHODS

In this retrospective population-based cohort study, a total of 137,530 preschoolers aged 3-5 years old (65,295/47.5% females and 72,235/52.5% males) were included in the final analysis. The Ages and Stages Questionnaires-Third Edition (ASQ-3) was completed by parents to evaluate children's neurodevelopment. The associations between GA and neurodevelopment were analyzed by a generalized additive mixed model with thin plate regression splines. Logistic regression was also conducted to examine the differences in children's development with different GAs.

RESULTS

There was a non-linear relationship between GA and children's neurodevelopmental outcomes with the highest scores at 40 weeks gestational age. The adjusted risks of GAs (very and moderately preterm, late-preterm, early-term, and post-term groups) on suspected developmental delays were observed in communication (OR were 1.83, 1.28, 1.13, and 1.21 respectively, each p < 0.05), gross motor skill (OR were 1.67, 1.38, 1.10, and 1.05 respectively, each p < 0.05), and personal social behavior (OR were 1.01, 1.36, 1.12, and 1.18 respectively, each p < 0.05). The adjusted OR of very and moderately preterm, late-preterm, and early-term were observed in fine motor skills (OR were 1.53, 1.22, and 1.09 respectively, each p < 0.05) and problem-solving (OR were 1.33, 1.12, and 1.06 respectively, each p < 0.05).

CONCLUSION

GAs is a risk factor for neurodevelopmental delays in preschoolers after controlling for a wide range of covariates, and 40-41 weeks may be the ideal delivery GA for optimal neurodevelopmental outcomes. Close observation and monitoring should be considered for early- and post-term born children as well as pre-term children.

Association of Gestational Age at Birth With Subsequent Suspected Developmental Coordination Disorder in Early Childhood in China

IMPORTANCE

It remains unknown whether children born at different degrees of prematurity, early term, and post term might have a higher risk of developmental coordination disorder (DCD) compared with completely full-term children (39-40 gestational weeks).

OBJECTIVE

To differentiate between suspected DCD in children with different gestational ages based on a national representative sample in China.

DESIGN, SETTING, AND PARTICIPANTS

A retrospective cohort study was conducted in China from April 1, 2018, to December 31, 2019. A total of 152 433 children aged 3 to 5 years from 2403 public kindergartens in 551 cities of China were included in the final analysis. A multilevel regression model was developed to determine the strength of association for different gestational ages associated with suspected DCD when considering kindergartens as clusters.

MAIN OUTCOMES AND MEASURES

Children's motor performance was assessed using the Little Developmental Coordination Disorder Questionnaire, completed by their parents. Gestational age was determined according to the mother's medical records and divided into 7 categories: completely full term (39 to 40 weeks' gestation), very preterm (<32 weeks), moderately preterm (32-33 weeks), late preterm (34-36 weeks), early term (37-38 weeks), late term (41 weeks), and post term (>41 weeks).

RESULTS

A total of 152 433 children aged 3 to 5 years (mean [SD] age, 4.5 [0.8] years), including 80 370 boys (52.7%) and 72 063 girls (47.3%), were included in the study. There were 45 052 children (29.6%) aged 3 years, 59 796 (39.2%) aged 4 years, and 47 585 (31.2%) aged 5 years. Children who were born very preterm (odds ratio [OR], 1.35; 95% CI, 1.23-1.48), moderately preterm (OR, 1.18; 95% CI, 1.02-1.36), late preterm (OR, 1.24; 95% CI, 1.16-1.32), early term (OR, 1.11; 95% CI, 1.06-1.16), and post term (OR, 1.17; 95% CI, 1.07-1.27) were more likely to be classified in the suspected DCD category on the Little Developmental Coordination Disorder Questionnaire than completely full-term children after adjusting for the same characteristics. Additionally, there was no association with suspected DCD in younger (aged 3 years) early-term and postterm children by stratified analyses.

CONCLUSIONS AND RELEVANCE

In this cohort study, every degree of prematurity at birth, early-term birth, and postterm birth were associated with suspected DCD when compared with full-term birth. These findings have important implications for understanding motor development in children born at different gestational ages. Long-term follow-up and rehabilitation interventions should be considered for children born early and post term.

Rates of Neuropsychiatric Disorders and Gestational Age at Birth in a Danish Population

IMPORTANCE

Nonoptimal gestational durations could be associated with neurodevelopmental disabilities, yet evidence regarding finer classification of gestational age and rates of multiple major neuropsychiatric disorders beyond childhood is limited.

OBJECTIVE

To comprehensively evaluate associations between 6 gestational age groups and rates of 9 major types and 8 subtypes of childhood and adult-onset neuropsychiatric disorders.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study evaluated data from a nationwide register of singleton births in Denmark from January 1, 1978, to December 31, 2016. Data analyses were conducted from October 1, 2019, through November 15, 2020.

EXPOSURES

Gestational age subgroups were classified according to data from the Danish Medical Birth Register: very preterm (20-31 completed weeks), moderately preterm (32-33 completed weeks), late preterm (34-36 completed weeks), early term (37-38 completed weeks), term (39-40 completed weeks, reference), and late or postterm (41-45 completed weeks).

MAIN OUTCOMES AND MEASURES

Neuropsychiatric diagnostic records (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes F00-F99) were ascertained from the Danish Psychiatric Central Register up to August 10, 2017. Poisson regression was used to estimate the incidence rate ratio (IRR) and 95% CI for neuropsychiatric disorders, adjusting for selected sociodemographic factors.

RESULTS

Of all 2 327 639 singleton births studied (1 194 925 male newborns [51.3%]), 22 647 (1.0%) were born very preterm, 19 801 (0.9%) were born moderately preterm, 99 488 (4.3%) were born late preterm, 388 416 (16.7%) were born early term, 1 198 605 (51.5%) were born at term, and 598 682 (25.7%) were born late or postterm. A gradient of decreasing IRRs was found from very preterm to late preterm for having any or each of the 9 neuropsychiatric disorders (eg, very preterm: IRR, 1.49 [95% CI, 1.43-1.55]; moderately preterm: IRR, 1.23 [95% CI, 1.18-1.28]; late preterm: IRR, 1.17 [95% CI, 1.14-1.19] for any disorders) compared with term births. Individuals born early term had 7% higher rates (IRR, 1.07 [95% CI, 1.06-1.08]) for any neuropsychiatric diagnosis and a 31% higher rate for intellectual disability (IRR, 1.31 [95% CI, 1.25-1.37]) compared with those born at term. The late or postterm group had lower IRRs for most disorders, except pervasive developmental disorders, for which the rate was higher for postterm births compared with term births (IRR, 1.06 [95% CI, 1.03-1.09]).

CONCLUSIONS AND RELEVANCE

Higher incidences of all major neuropsychiatric disorders were observed across the spectrum of preterm births. Early term and late or postterm births might not share a homogeneous low risk with individuals born at term. These findings suggest that interventions that address perinatal factors associated with nonoptimal gestation might reduce long-term neuropsychiatric risks in the population.

An EPIC predictor of gestational age and its application to newborns conceived by assisted reproductive technologies

Background

Gestational age is a useful proxy for assessing developmental maturity, but correct estimation of gestational age is difficult using clinical measures. DNA methylation at birth has proven to be an accurate predictor of gestational age. Previous predictors of epigenetic gestational age were based on DNA methylation data from the Illumina HumanMethylation 27 K or 450 K array, which have subsequently been replaced by the Illumina MethylationEPIC 850 K array (EPIC). Our aims here were to build an epigenetic gestational age clock specific for the EPIC array and to evaluate its precision and accuracy using the embryo transfer date of newborns from the largest EPIC-derived dataset to date on assisted reproductive technologies (ART).

Methods

We built an epigenetic gestational age clock using Lasso regression trained on 755 randomly selected non-ART newborns from the Norwegian Study of Assisted Reproductive Technologies (START)—a substudy of the Norwegian Mother, Father, and Child Cohort Study (MoBa). For the ART-conceived newborns, the START dataset had detailed information on the embryo transfer date and the specific ART procedure used for conception. The predicted gestational age was compared to clinically estimated gestational age in 200 non-ART and 838 ART newborns using MM-type robust regression. The performance of the clock was compared to previously published gestational age clocks in an independent replication sample of 148 newborns from the Prediction and Prevention of Preeclampsia and Intrauterine Growth Restrictions (PREDO) study—a prospective pregnancy cohort of Finnish women.

Results

Our new epigenetic gestational age clock showed higher precision and accuracy in predicting gestational age than previous gestational age clocks (R² = 0.724, median absolute deviation (MAD) = 3.14 days). Restricting the analysis to CpGs shared between 450 K and EPIC did not reduce the precision of the clock. Furthermore, validating the clock on ART newborns with known embryo transfer date confirmed that DNA methylation is an accurate predictor of gestational age (R² = 0.767, MAD = 3.7 days).

Conclusions

We present the first EPIC-based predictor of gestational age and demonstrate its robustness and precision in ART and non-ART newborns. As more datasets are being generated on the EPIC platform, this clock will be valuable in studies using gestational age to assess neonatal development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13148-021-01055-z.

Shiftwork and Light at Night Negatively Impact Molecular and Endocrine Timekeeping in the Female Reproductive Axis in Humans and Rodents

Shiftwork, including work that takes place at night (nightshift) and/or rotates between day and nightshifts, plays an important role in our society, but is associated with decreased health, including reproductive dysfunction. One key factor in shiftwork, exposure to light at night, has been identified as a likely contributor to the underlying health risks associated with shiftwork. Light at night disrupts the behavioral and molecular circadian timekeeping system, which is important for coordinated timing of physiological processes, causing mistimed hormone release and impaired physiological functions. This review focuses on the impact of shiftwork on reproductive function and pregnancy in women and laboratory rodents and potential underlying molecular mechanisms. We summarize the negative impact of shiftwork on female fertility and compare these findings to studies in rodent models of light shifts. Light-shift rodent models recapitulate several aspects of reproductive dysfunction found in shift workers, and their comparison with human studies can enable a deeper understanding of physiological and hormonal responses to light shifts and the underlying molecular mechanisms that may lead to reproductive disruption in human shift workers. The contributions of human and rodent studies are essential to identify the origins of impaired fertility in women employed in shiftwork.

Association of Gestational Age at Birth With Brain Morphometry

IMPORTANCE

Preterm and postterm births are associated with adverse neuropsychiatric outcomes. However, it remains unclear whether variation of gestational age within the 37- to 42-week range of term deliveries is associated with neurodevelopment.

OBJECTIVE

To investigate the association of gestational age at birth (GAB) with structural brain morphometry in children aged 10 years.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort study included pregnant women living in Rotterdam, the Netherlands, with an expected delivery date between April 1, 2002, and January 31, 2006. The study evaluated 3079 singleton children with GAB ranging from 26.3 to 43.3 weeks and structural neuroimaging at 10 years of age from the Generation R Study, a longitudinal, population-based prospective birth cohort from early pregnancy onward in Rotterdam. Data analysis was performed from March 1, 2019, to February 28, 2020, and at the time of the revision based on reviewer suggestions.

EXPOSURES

The GAB was calculated based on ultrasonographic assessment of crown-rump length (<12 weeks 5 days) or biparietal diameter (≥12 weeks 5 days) in dedicated research centers.

MAIN OUTCOMES AND MEASURES

Brain structure, including global and regional brain volumes and surface-based cortical measures (thickness, surface area, and gyrification), was quantified by magnetic resonance imaging.

RESULTS

In the 3079 children (1546 [50.2%] female) evaluated at 10 years of age, GAB was linearly associated with global and regional brain volumes. Longer gestational duration was associated with larger brain volumes; for example, every 1-week-longer gestational duration corresponded to an additional 4.5 cm3/wk (95% CI, 2.7-6.3 cm3/wk) larger total brain volume. These associations persisted when the sample was restricted to children born at term (GAB of 37-42 weeks: 4.8 cm3/wk; 95% CI, 1.8-7.7 cm3/wk). No evidence of nonlinear associations between GA and brain morphometry was observed.

CONCLUSIONS AND RELEVANCE

In this cohort study, gestational duration was linearly associated with brain morphometry during childhood, including within the window of term delivery. These findings may have marked clinical importance, particularly given the prevalence of elective cesarean deliveries.

Risk factors for attention-deficit/hyperactivity disorder: a case-control study in 5 to 12 years old children

BACKGROUND AND AIMS

Attention deficit/hyperactivity disorder (ADHD) is a common neurodevelopmental disorder known by a pattern of diminished sustained attention and increased impulsivity or hyperactivity. This study aimed to evaluate the risk factors associated with ADHD.

METHODS

This case-control study included 297 ADHD children aged 5-12 years admitted to Tehran Institute of Psychiatry, Iran (2012-2013). They were compared with 297 non-ADHD (as controls matched to cases 1:1) who were of the same age (±1 years) selected from outpatients in general pediatric medical centers in Tehran. ADHD Rating Scale IV (ADHD-RS-IV)-Home Version was used to confirm ADHD. Data were analyzed using conditional binary logistic regression.

RESULTS

Mean±SD age were 8.18±3.11 and 8.11±2.9 years in the case and control groups, respectively (P=0.61). Mean±SD birth weight (BW) was higher in ADHD patients compared with the controls (3245.09±0.66 vs 3026.56±0.45 gr, P=0.045). The results showed that odds of ADHD in children with high BW (>3500g) was 3.36 (1.96-5.78) times the odds of ADHD in normal BW children (2500-3500g) controlling for other risk factors. ADHD risk in low BW children (<2500 g) was not statistically different compared with normal BW children [OR:1.74 (0.7-3.7)]. Experience of neonatal disease, fewer offspring, lower level of mothers' education, and preterm delivery were also risk factors for higher odds of ADHD.

CONCLUSION

Based on our sample, preterm birth, neonatal disease, high BW, lower level of mother's education, and fewer offspring were ADHD risk factors.

Does Birth Trigger Cell Death in the Developing Brain?

Developmental cell death eliminates half of the neurons initially generated in the mammalian brain, and occurs perinatally in many species. It is possible that the timing of neuronal cell death is developmentally programmed, and only coincidentally associated with birth. Alternatively, birth may play a role in shaping cell death. To test these competing hypotheses, we experimentally advanced or delayed birth by 1 d in mice (within the normal range of gestation for the species) and examined effects on the temporal pattern and magnitude (amount) of neuronal cell death, using immunohistochemical detection of activated caspase-3 as a cell death marker. In order to detect effects of subtle changes in birth timing, we focused on brain areas that exhibit sharp postnatal peaks in cell death. We find that advancing birth advances peak cell death, supporting the hypothesis that birth triggers cell death. However, a delay of birth does not delay cell death. Thus, birth can advance cell death, but if postponed, a developmental program governs. Advancing or delaying birth also caused region-specific changes in the overall magnitude of cell death. Our findings shed light on the long-standing question of what controls the timing and magnitude of developmental neuronal cell death, and position birth as an orchestrator of brain development. Because humans across the world now routinely alter birth timing, these findings may have implications for current obstetric practices.

Cerebral disorders in the first 7 years of life in children born post-term: a cohort study

Background

To estimate the association between post-term delivery and risk of physical disabilities, mental disabilities, and seizures during the first 7 years of life.

Methods

Data from 57,884 singleton infants born alive in week 39–45 by mothers included in the Danish National Birth Cohort (1997 to 2004) were analyzed, of these 51,268 were born at term (39–41 + 6) and 6616 post-term (42 + 0–44 + 6). Information on clinical endpoints was obtained from an interview at 18 months of gestational age, from a 7-year questionnaire, and from the Danish National Patient Register.

Logistic regression and Cox regression were used to estimate odds ratios and hazard rate ratios for the outcome obtained from the interview/questionnaire data and from the register-based data, respectively.

Results

We found no statistically significant increased risk of physical disabilities, mental disabilities, and epilepsy among children born post-term, though for most outcomes studied a tendency towards more adverse outcomes was seen. When children born late term (week 41) were compared to children born in week 42 or later the same tendency was found.

Conclusion

Post-term born children had a tendency to an excess risk of neurological disabilities as followed for up to 7 years of age.

Early-life social and health determinants of adult socioeconomic position: associations and trends across generations

Background

Social and biological circumstances at birth are established predictors of adult socioeconomic position (SEP). This study aims to assess the trends in these associations across two generations and examine the effects of parental early-life characteristics on descendants’ adult SEP.

Methods

We studied men and women born in the Uppsala University Hospital 1915–1929 (G1) and their offspring born 1932–1960 (G2). Data were collected in archives and routine registers. Adult SEP was assessed as an aggregate measure combining education and occupation. The exposures were family SEP, mother’s marital status, mother’s parity, mother’s age, standardised birth weight, gestational length and birth multiplicity. Linear regression was used to examine the associations across generations.

Results

The difference in adult SEP between low and high family SEP at birth was 15.8 (95% CI: 13.3 to 18.3) percentage points smaller in G2 compared with G1, although a considerable difference was still evident in G2. The associations of adult SEP with small birth weight for gestational age, post-term birth and high parity were stable between the generations: the generational differences in adjusted coefficients were 1.5 (95% CI: −1.1 to 4.1), 0.6 (–1.7 to 2.9) and 1.8 (–0.2 to 3.8) percentage points, respectively. The association between grandparental and grandchildren’s SEPs was largely explained by parental socioeconomic conditions. Father’s preterm birth was independently associated with offspring’s SEP.

Conclusion

The stability of the associations between early-life biological disadvantages and adult SEP and the persistent, although attenuated, association between early-life and adult SEPs necessitates increased policy attention to both social and health conditions at birth.

Protective effect of high zinc levels on preterm birth induced by mercury exposure during pregnancy: A birth cohort study in China

OBJECTIVE

The aims of our study were to determine whether prenatal mercury levels are associated with the risk of preterm birth (PTB) and whether high maternal serum zinc (Zn) levels alleviate any negative effects of maternal mercury (Hg) exposure regarding PTB.

METHODS

Serum concentrations of Zn and Hg were measured in 3025 pregnant women from the Ma'anshan Birth Cohort. Before the collection of blood samples, they underwent examinations via the completion of questionnaires. The delivery records of the women were obtained from a series of medical records. We divided the study population into tertiles according to the participants' Hg levels: the low-Hg group (the first tertile, <0.30 μg/L), the medium-Hg group (the second tertile, 0.30-0.43 μg/L) and the high-Hg group (the third tertile, ≥0.43 μg/L). The associations of Hg exposure with both the risk of PTB and gestational age (weeks) at birth were estimated using a binary logistic regression model and multivariable linear regression analysis, respectively. Afterwards, we conducted a repeated analyses test after the participants were stratified according to their Zn levels, using the 75th percentile division method.

RESULTS

Overall, the medians and the interquartile ranges of Hg and Zn in the second trimester were 0.36 (0.27, 0.48) μg/L and 812.34 (731.26, 896.59) μg/L, respectively. Hg levels were associated with PTB [adjusted odds ratio (OR) and 95% confidence interval (95% CI): 1.91 (1.17, 3.12) for the third tertile vs. the first tertile of the serum Hg levels]. In the stratification analysis of the participants in the low-Zn group, the high-Hg group exhibited a significant odds ratio of PTB [adjusted OR (95% CI): 1.87 (1.08, 3.24)], compared to the low-Hg group. However, in the participants from the high-Zn group, the high-Hg group exhibited a non-significant OR of PTB [adjusted OR (95% CI): 2.32 (0.73, 7.42)]. In the multivariate linear regression analysis, gestational age (weeks) at delivery was significantly and inversely associated with the ln-transformed Hg concentrations [adjusted β (95% CI): -0.16 (-0.26, -0.06)]. Similarly, after the stratification analysis in the high-Zn group, there were no significant associations between PTB and the Hg levels [adjusted β (95% CI): -0.12 (-0.33, 0.09)].

CONCLUSION

Prenatal Hg exposure adversely affected PTB, and high Zn levels alleviate this effect, which indicates that a more stringent control of Hg and a sufficient intake of Zn are necessary to help birth outcomes.

Association between maternal and umbilical cord serum cobalt concentration during pregnancy and the risk of preterm birth: The Ma'anshan birth cohort (MABC) study

Cobalt is an essential trace element and has been suggested to be involved in oxidative stress and inflammatory responses. However, researches have paid little attention to the association between serum cobalt levels during pregnancy and the risk of preterm birth (PTB, <37 week of gestation). The purpose of this study was to determine the association between maternal and umbilical cord serum cobalt concentrations and the risk of PTB. A total of 2951, 3080, and 2698 serum samples were obtained from pregnant women in the first, the second trimester, and the umbilical cord blood, respectively. The tertile levels of ln-transformed cobalt were defined as low, medium and high levels for cobalt respectively. In our study, the rate of PTB (<37 weeks of gestation) was elevated in subjects with low cobalt levels in the first trimester of pregnancy (adjusted OR 1.61, 95% CI: 1.01, 2.58) and the second trimester of pregnancy (adjusted OR 1.62, 95% CI: 1.03, 2.54). The adjusted OR for PTB was 2.46 (95% CI: 1.34, 4.53) among subjects with low cobalt levels and 2.22 (95% CI: 1.19, 4.15) among subjects with medium cobalt levels in the umbilical cord serum. Our findings demonstrated that the lower levels in maternal and umbilical cord serum cobalt were associated with the increased the risk of PTB.

Estimating uterine source current during contractions using magnetomyography measurements

Understanding the uterine source of the electrophysiological activity of contractions during pregnancy is of scientific interest and potential clinical applications. In this work, we propose a method to estimate uterine source currents from magnetomyography (MMG) temporal course measurements on the abdominal surface. In particular, we develop a linear forward model, based on the quasistatic Maxwell’s equations and a realistic four-compartment volume conductor, relating the magnetic fields to the source currents on the uterine surface through a lead-field matrix. To compute the lead-field matrix, we use a finite element method that considers the anisotropic property of the myometrium. We estimate the source currents by minimizing a constrained least-squares problem to solve the non-uniqueness issue of the inverse problem. Because we lack the ground truth of the source current, we propose to predict the intrauterine pressure from our estimated source currents by using an absolute-value-based method and compare the result with real abdominal deflection recorded during contractile activity. We test the feasibility of the lead-field matrix by displaying the lead fields that are generated by putative source currents at different locations in the myometrium: cervix and fundus, left and right, front and back. We then illustrate our method by using three synthetic MMG data sets, which are generated using our previously developed multiscale model of uterine contractions, and three real MMG data sets, one of which has simultaneous real abdominal deflection measurements. The numerical results demonstrate the ability of our method to capture the local contractile activity of human uterus during pregnancy. Moreover, the predicted intrauterine pressure is in fair agreement with the real abdominal deflection with respect to the timing of uterine contractions.

Umbilical Serum Copper Status and Neonatal Birth Outcomes: a Prospective Cohort Study

Our study aimed to assess the distribution of copper (Cu) in umbilical cord serum and estimated the association between umbilical serum Cu status and neonatal birth outcomes in a Chinese population. Through the Ma'anShan Birth Cohort Study, 2689 maternal-singleton pairs with detailed birth records and available serum samples were identified. The tertile levels of ln-transformed Cu were used to define low, medium, and high levels for serum Cu. The median for umbilical cord serum Cu was 298.2 μg/L with a range of 123.1-699.6 μg/L in this study population. Our study found a positive association between the concentration of serum Cu in the umbilical cord and the duration of gestation. Compared with medium Cu levels, we found that infants with low Cu levels had a significant higher risk of preterm birth (OR = 5.06, 95% CI 2.74, 9.34) and early-term birth (OR = 1.36, 95% CI 1.10, 1.69) in the crude model. We also found that infants with high Cu levels had a significant higher risk of late- or post-term birth (OR = 1.47, 95% CI 1.11, 1.95). A significant higher risk of preterm, early-term, and late- or post-term birth still remained, even after adjustment for potential confounding factors. Our findings suggested that both Cu deficiency and Cu overload had an adverse effect on neonatal birth outcomes.

Gestational age at birth and academic performance: population-based cohort study

Background

Numerous studies suggest pre-term birth is associated with cognitive deficit. However, less is known about cognitive outcomes following post-term birth, or the influence of weight variations within term or post-term populations. We examined associations between gestational age (GA) and school performance, by weight-for-GA, focusing on extremely pre- and post-term births.

Method

Record linkage study of Swedish children born 1973-94 ( n =  2 008 102) with a nested sibling comparison ( n =  439 629). We used restricted cubic regression splines to examine associations between GA and the grade achieved on leaving secondary education, comparing siblings to allow stronger causal inference with regard to associations between GA and school performance.

Results

Grade averages of both pre- and post-term children were below those of full-term counterparts and lower for those born small-for-GA. The adjusted grades of extremely pre-term children (at 24 completed weeks), while improving in later study periods, were lower by 0.43 standard deviations (95% confidence interval 0.38-0.49), corresponding with a 21-point reduction (19 to 24) on a 240-point scale. Reductions for extremely post-term children (at 45 completed weeks) were lesser [-0.15 standard deviation (-0.17 to -0.13) or -8 points (-9 to -7)]. Among matched siblings, we observed weaker residual effects of pre-term and post-term GA on school performance.

Conclusions

There may be independent effects of fetal maturation and fetal growth on school performance. Associations among matched siblings, although attenuated, remained consistent with causal effects of pre- and post-term birth on school performance.

Origins and Predictors of Friendships in 6- to 8-Year-Old Children Born at Neonatal Risk

OBJECTIVE

To test effects of gestational age (GA), early social experiences, and child characteristics on children's friendships and perceived peer acceptance.

STUDY DESIGN

As part of the prospective Bavarian Longitudinal Study (1147 children, 25-41 weeks GA), children's friendships (eg, number of friends, frequency of meeting friends) and perceived peer acceptance were assessed before school entry (6 years of age) and in second grade (8 years of age) using child and parent reports. The parent-infant relationship was evaluated during the 5 months after birth. Child characteristics (ie, height, motor impairment, cognitive ability, behavioral problems) were measured at 6 years of age. Multiple regressions estimated effects of GA, parent-infant relationship, and child characteristics.

RESULTS

Overall, children with higher GA had more friends, spent more time with friends, and were more accepted by peers at 6 years of age. Better parent-infant relationships, higher cognitive abilities, and fewer motor and behavioral problems predicted more friendships and higher peer acceptance after adjusting for sex, socioeconomic status, multiples, siblings, and special schooling. Across all GA groups, number of friends (child report: mean change, 1.77; 95% CI, 1.57-1.96) and peer acceptance (child report: mean change, 0.14; 95% CI, 0.09-0.19; parent report: mean change, 0.14; 95% CI, 0.11-0.17) increased with age, but the increase in number of friends was higher among preterm children (ie, interaction effect age*GA group: P = .034).

CONCLUSIONS

Our results provide evidence of a dose-response effect of low GA on children's friendships and perceived peer acceptance. Improvements in early parenting and motor, cognitive, and behavioral development may facilitate friendships and peer acceptance for all children across the gestation spectrum.

Gestational age at birth and risk of intellectual disability without a common genetic cause

Preterm birth is linked to intellectual disability and there is evidence to suggest post-term birth may also incur risk. However, these associations have not yet been investigated in the absence of common genetic causes of intellectual disability, where risk associated with late delivery may be preventable. We therefore aimed to examine risk of intellectual disability without a common genetic cause across the entire range of gestation, using a matched-sibling design to account for unmeasured confounding by shared familial factors. We conducted a population-based retrospective study using data from the Stockholm Youth Cohort (n = 499,621) and examined associations in a nested cohort of matched outcome-discordant siblings (n = 8034). Risk of intellectual disability was greatest among those born extremely early (adjusted OR_{24 weeks} = 14.54 [95% CI 11.46-18.44]), lessening with advancing gestational age toward term (aOR_{32 weeks} = 3.59 [3.22-4.01]; aOR_37weeks = 1.50 [1.38-1.63]); aOR_{38 weeks} = 1.26 [1.16-1.37]; aOR₃₉ weeks = 1.10 [1.04-1.17]) and increasing with advancing gestational age post-term (aOR_{42 weeks} = 1.16 [1.08-1.25]; aOR_{43 weeks} = 1.41 [1.21-1.64]; aOR_{44 weeks} = 1.71 [1.34-2.18]; aOR_{45 weeks} = 2.07 [1.47-2.92]). Associations persisted in a cohort of matched siblings suggesting they were robust against confounding by shared familial traits. Risk of intellectual disability was greatest among children showing evidence of fetal growth restriction, especially when birth occurred before or after term. Birth at non-optimal gestational duration may be linked causally with greater risk of intellectual disability. The mechanisms underlying these associations need to be elucidated as they are relevant to clinical practice concerning elective delivery around term and mitigation of risk in post-term children.

Research Review: The role of obstetric and neonatal complications in childhood attention deficit and hyperactivity disorder - a systematic review

BACKGROUND

Attention deficit and hyperactivity disorder (ADHD) is a developmental disorder characterized by an inability to sustain attention, activity levels and impulse control, and, according to the latest studies, the prevalence is about 8% and in some countries less than 1%. Currently, it is well-known that complications during the perinatal period have significant implications on child's physical and mental health. Purpose of the present paper is to review the literature about the association between perinatal complications and future risk of an ADHD diagnosis.

METHODS

A research in the main database sources has been conducted to obtain a systematic review on the perinatal risk factors of ADHD.

RESULTS

Among perinatal complications, available data indicate low birth weight (LBW) (Cohen's d effect size range: 0.31-1.64-small effect size) and preterm birth (PB) (range d: 0.41-0.68) as the most important factors associated with a future diagnosis of ADHD.

CONCLUSIONS

PB and LBW children should be carefully monitored for an early diagnosis of ADHD limiting the impact of the disease in life span. A systematic review focusing on these risk factors have not been published until now, in the next future preventive strategies should be developed in order to minimize ADHD onset.

Influence of exposure to perinatal risk factors and parental mental health related hospital admission on adolescent deliberate self-harm risk

Adolescent deliberate self-harm (DSH) has been found to be associated with a range of bio-psycho-social factors. Simultaneous investigations of these factors enable more robust estimation of the independent effect of a specific risk factor by adjusting for a more complete set of covariates. However, few studies have had the ability to examine all of these factors together. This study used the linkage of population-level de-identified data collections from government agencies to investigate a range of biological, psychological, and social risk factors and their effects on adolescent risk of DSH (with or without suicidal intent). The investigation was undertaken by progressively adjusting for plausible covariates, including fetal growth status and birth order, early familial social factors, parental hospital admissions due to psychiatric disorders or DSH, and parental all-cause death. Conditional logistic regression was used for data analysis. Children's psychiatric history was analysed to examine the extent to which it may account for the link between the risk factors and adolescent DSH risk. This study identified significant biological and perinatal social risk factors for adolescent DSH risk, including overdue birth, high birth order (≥2), single or teen/young motherhood, high neighbourhood socioeconomic disadvantage, and parental psychiatric and/or DSH-related hospital admissions. Further, parental psychiatric and/or DSH-related admissions, and children's psychiatric admissions in particular, largely attenuated the effects of the perinatal social risk factors but not the biological factors on adolescent DSH risk. These results highlight the importance of taking joint actions involving both health and social services in the prevention of adolescent DSH.

Risk factors for comorbid oppositional defiant disorder in attention-deficit/hyperactivity disorder

Oppositional defiant disorder (ODD) is highly prevalent in attention-deficit/hyperactivity disorder (ADHD). Individuals with both ADHD and ODD (ADHD + ODD) show a considerably worse prognosis compared with individuals with either ADHD or ODD. Therefore, identification of risk factors for ADHD + ODD is essential and may contribute to the development of (early) preventive interventions. Participants were matched for age, gender, and ADHD-subtype (diagnostic groups), and did not differ in IQ. Predictors included pre- and perinatal risk factors (pregnancy duration, birth weight, maternal smoking during pregnancy), transgenerational factors (parental ADHD; parental warmth and criticism in diagnostic groups), and postnatal risk factors (parental socioeconomic status [SES], adverse life events, deviant peer affiliation). Three models were assessed, investigating risk factors for ADHD-only versus controls (N = 86), ADHD + ODD versus controls (N = 86), and ADHD + ODD versus ADHD-only (N = 90). Adverse life events and parental ADHD were risk factors for both ADHD + ODD and ADHD-only, and more adverse life events were an even stronger risk factor for comorbid ODD compared with ADHD-only. For ADHD + ODD, but not ADHD-only, parental criticism, deviant peer affiliation, and parental SES acted as risk factors. Maternal smoking during pregnancy acted as minor risk factor for ADHD-only, while higher birth weight acted as minor risk factor for ADHD + ODD. No effects of age were present. Findings emphasise the importance of these factors in the development of comorbid ODD. The identified risk factors may prove to be essential in preventive interventions for comorbid ODD in ADHD, highlighting the need for parent-focused interventions to take these factors into account.

Pre-term and post-term births: predictors and implications on neonatal mortality in Northern Ethiopia

BACKGROUND

Pre-term and post-term births are major determinants of neonatal mortality, including short- and long-term morbidity. In developing countries, where pre-term and post-term births are disproportionately common, the magnitude and underlying causes are not well understood, and evidence is required to design appropriate interventions. This study measured the incidence and identified risk factors of pre-term birth and post-term births in Ethiopia. In addition, it examined the effects of pre-term and post-term birth on neonatal mortality.

METHOD

This study is a portion of prospective cohort study conducted on 1152 live births born between April and July 2014 in seven hospitals in Tigray region, Northern Ethiopia. Neonatal mortality and birth outcomes were considered as dependent variables. Data were collected using a structured questionnaire and weekly neonatal follow up directed at midwives. Data were described using frequency, percentage, ratio of relative risk (RRR), and 95 % confidence interval (CI). We used multinomial and binary logistic regression to identify independent predictors of birth outcome and neonatal mortality respectively.

RESULT

The prevalence of pre-term and post term births was 8.1 % and 6.0 % respectively. Underweight maternal body mass index (RRR: 0.47, CI: 0.22-0.99), medium reported income (RRR: 0.26, CI: 0.12-0.5), length of neonate (RRR: 0.05, CI: 0.01-0.41), and multiple births (RRR: 2.86, CI: 1.4-5.650) were associated with pre-term birth. Predictors for post-term birth were overweight maternal body mass index (RRR: 3.88, CI: 1.01-15.05), high reported income mothers (RRR: 2.17, CI:1.1-4.3), as well as unmarried, widowed and divorced marital status (RRR:2.43, CI:1.02-5.80). With regards to binary logistic regression, pre-term birth (RR: 2.45, CI: 1.45-4.04) was an independent predictor for neonatal mortality, but this was not true for post-term births (RR: 0.45, CI: 0.07-2.96).

CONCLUSION

Socioeconomic and proximate factors are important predictors for pre-term and post-term births. Empowering women in terms of income status and controlling body mass index within the normal range are recommended. In addition, early detection and close antenatal follow-ups for mothers, who are at risk before and during pregnancy, are necessary to prevent both pre-term and post-term births.

Gestational Age at Term, Delivery Circumstance, and Their Association with Childhood Attention Deficit Hyperactivity Disorder Symptoms

BACKGROUND

Perinatal characteristics may identify subgroups of term-born children at risk for academic and behavioural difficulties. Using follow-up data from the Pregnancy Outcomes and Community Health Study, we subdivided term births according to two potential markers of perinatal risk (gestational age, delivery circumstance) and evaluated their association with attention deficit hyperactivity disorder (ADHD) symptoms.

METHODS

We included children born at term whose mothers completed the Conners' Parent Rating Scales-Revised-Short Form (CPRS-R-S) (n = 610; ages: 3-9 years). The CPRS-R-S yields age and sex-referenced T-scores for the two primary dimensions of ADHD (inattention, hyperactivity) and an ADHD Index that reflects both dimensions. Using general linear models, we evaluated whether: (1) term delivery defined by gestational week (reference: 39-40 weeks), or (2) term delivery circumstance defined by labour onset type and mode of delivery (reference: spontaneous labour, vaginal delivery) was associated with these problems.

RESULTS

Following adjustment for parity, sociodemographics, and maternal mental health both during pregnancy and at the child follow-up survey, the induced labour plus caesarean group exhibited higher inattention and ADHD Index scores relative to the spontaneous labour, vaginal delivery group (inattention: mean difference = 5.1, 95% CI 0.6, 9.7; ADHD Index: mean difference = 4.1, 95% CI 0.5, 7.8). Findings were primarily driven by male children.

CONCLUSIONS

Among term-born children, only those whose mothers experienced induction of labour that culminated in caesarean delivery exhibited higher levels of ADHD symptoms. Prenatal, antepartum, and/or postnatal factors associated with this delivery profile may reflect increased risk for such problems.

Gestational age and adolescent mental health: evidence from Hong Kong's 'Children of 1997' birth cohort

BACKGROUND

Preterm, and more recently early term, birth has been identified as a risk factor for poor health. Whether the sequelae of late preterm or early term birth extends to poor mental health and well-being in adolescence is unclear and has not been systematically assessed.

METHOD

Linear regression was used to assess the adjusted associations of gestational age (very/moderate preterm (<34 weeks, n=85), late preterm (34-36 weeks, n=305), early term (37-38 weeks, n=2228), full term (39-40 weeks, n=4018), late term (41 weeks, n=809), post-term (≥42 weeks, n=213)) with self-reported self-esteem at ∼11 years (n=6935), parent-reported Rutter score assessing the common emotional and behavioural problems at ∼7 years (n=6292) and ∼11 years (n=5596) and self-reported depressive symptoms at ∼13 years (n=5795) in a population-representative Hong Kong Chinese birth cohort 'Children of 1997' where gestational age has little social patterning.

RESULTS

Very/moderate preterm birth was associated with higher Rutter subscore for hyperactivity (ß coefficients 0.5, 95% CI 0.01 to 1.00) at ∼7 years but not at ∼11 years, adjusted for sex, age, socio-economic position, parents' age at birth, birth order and secondhand smoke exposure. Similarly adjusted, late preterm, early term, late term and post-term birth were not associated with self-esteem or depressive symptoms.

CONCLUSIONS

In a population-representative birth cohort from a non-Western-developed setting, gestational age had few associations with mental health and well-being in adolescence, whereas very preterm birth was specifically associated with hyperactivity in childhood. Inconsistencies with studies from Western settings suggest setting specific unmeasured confounding may underlie any observed associations.

Late preterm birth, post-term birth, and abnormal fetal growth as risk factors for severe mental disorders from early to late adulthood

BACKGROUND

Late preterm births constitute the majority of preterm births. However, most evidence suggesting that preterm birth predicts the risk of mental disorders comes from studies on earlier preterm births. We examined if late preterm birth predicts the risks of severe mental disorders from early to late adulthood. We also studied whether adulthood mental disorders are associated with post-term birth or with being born small (SGA) or large (LGA) for gestational age, which have been previously associated with psychopathology risk in younger ages.

METHOD

Of 12 597 Helsinki Birth Cohort Study participants, born 1934-1944, 664 were born late preterm, 1221 post-term, 287 SGA, and 301 LGA. The diagnoses of mental disorders were identified from national hospital discharge and cause of death registers from 1969 to 2010. In total, 1660 (13.2%) participants had severe mental disorders.

RESULTS

Individuals born late preterm did not differ from term-born individuals in their risk of any severe mental disorder. However, men born late preterm had a significantly increased risk of suicide. Post-term birth predicted significantly increased risks of any mental disorder in general and particularly of substance use and anxiety disorders. Individuals born SGA had significantly increased risks of any mental and substance use disorders. Women born LGA had an increased risk of psychotic disorders.

CONCLUSIONS

Although men born late preterm had an increased suicide risk, late preterm birth did not exert widespread effects on adult psychopathology. In contrast, the risks of severe mental disorders across adulthood were increased among individuals born SGA and individuals born post-term.

Preterm and postterm birth in immigrant- and Swedish-born parents: a population register-based study

Ethnic minorities/immigrant groups tend to have increased risk for preterm birth. Less is known about this risk in diverse immigrant groups, couples of mixed ethnic-origin and in relation to duration of residence. Data from the Swedish Medical Birth Register on 1,028,303 mothers who gave birth to 1,766,026 singleton live born infants (1982-2002), was linked to the Education and Total Population Registers. Immigrant parents were identified by country of birth. Risk of early preterm, late preterm and postterm birth was analyzed using multinomial logistic regression. Polish, Yugoslavian, Iranian, South Asian, East Asian and Sub-Saharan African parents, Swedish mothers who had children with non-Swedish fathers, and parents from two different immigrant groups had higher risk of early preterm birth [adjusted relative risk (RR) (95% CI) 1.76 (1.24-2.50), 1.57 (1.31-1.87), 1.67 (1.30-2.14), 1.52 (1.07-2.16), 1.51 (1.08-2.10), 2.03 (1.32-3.12), 1.56 (1.45-1.67), and 1.55 (1.35-1.77) respectively] compared to Swedish-born parents. South Asian, Sub-Saharan African, and East Asian immigrants had a higher risk of late preterm birth compared to Swedish-born parents. North African and Middle Eastern, Somali, and Ethiopian/Eritrean groups had increased risk of postterm birth [adjusted RR 1.31 (1.16-1.47), 2.57 (2.31-2.86), 1.85 (1.67-2.04) respectively]. Adjustment for covariates did not substantially change associations. Immigrant mothers resident <3 years had higher risk for early preterm and postterm birth compared to residents >10 years [adjusted RR 1.46 (1.24-1.71) and 1.16 (1.11-1.23) respectively]. In addition to higher risk of preterm birth in select immigrant groups, some immigrant groups are also at higher risk of postterm birth. Shorter duration of residence is associated with higher risk of non-term deliveries.

Preterm birth and its long-term effects: methylation to mechanisms

The epigenetic patterns established during development may influence gene expression over a lifetime and increase susceptibility to chronic disease. Being born preterm (<37 weeks of gestation) is associated with increased risk mortality and morbidity from birth until adulthood. This brief review explores the potential role of DNA methylation in preterm birth (PTB) and its possible long-term consequences and provides an overview of the physiological processes central to PTB and recent DNA methylation studies of PTB.

Too heavy, too late: investigating perinatal health outcomes in immigrants residing in Spain. A cross-sectional study (2009-2011)

BACKGROUND

Studies have shown that immigrants residing in Spain have lower risks of delivering low birthweight (LBW) and preterm babies despite their socioeconomic disadvantages (the healthy migrant paradox). However, less is known about other important perinatal outcomes derived from birth weight and gestational age such as macrosomia and post-term birth. This paper aims to compare the main indicators related to birth weight and gestational age (LBW, macrosomia, preterm and post-term) for immigrants and Spaniards.

METHODS

Cross-sectional study based on the Spanish vital statistics for years 2009-2011. Multinomial regression models were performed to obtain crude and adjusted ORs and their 95% CIs.

RESULTS

After adjusting for known confounders, compared with Spaniards, most immigrant groups show lower or not significantly different risks of delivering LBW (OR between 0.65 and 0.87) or, more exceptionally, preterm babies (between 0.75 and 0.93). However, most of them also show higher risks of delivering macrosomic (OR between 1.21 and 2.58) and post-term babies (OR between 1.11 and 1.50). Mothers from sub-Saharan Africa show a higher risk in all perinatal outcomes studied.

CONCLUSIONS

The immigrant health paradox should be carefully assessed in comprehensive terms. Together with a predominantly lower risk of LBW, most immigrants have a higher risk of macrosomia, post-term and preterm births. These results have policy-making implications since studying the right tail of the birth weight and gestational age distributions implies considering a different set of risk factors.

Environmental risk factors by gender associated with attention-deficit/hyperactivity disorder

BACKGROUND

Early environmental risk factors associated with attention-deficit/hyperactivity disorder (ADHD) have been increasingly suggested. Our study investigates the maternal, pregnancy, and newborn risk factors by gender for children prescribed stimulant medication for treatment of ADHD in Western Australia.

METHODS

This is a population-based, record linkage case-control study. The records of all non-Aboriginal children and adolescents born in Western Australia and aged <25 years who were diagnosed with ADHD and prescribed stimulant medication (cases = 12,991) were linked to the Midwives Notification System (MNS) to obtain maternal, pregnancy, and birth information. The control population of 30,071 children was randomly selected from the MNS.

RESULTS

Mothers of children with ADHD were significantly more likely to be younger, be single, have smoked in pregnancy, have labor induced, and experience threatened preterm labor, preeclampsia, urinary tract infection in pregnancy, or early term delivery irrespective of the gender of the child, compared with the control group. In the fully adjusted model, a novel finding was of a possible protective effect of oxytocin augmentation in girls. Low birth weight, postterm pregnancy, small for gestational age infant, fetal distress, and low Apgar scores were not identified as risk factors.

CONCLUSIONS

Smoking in pregnancy, maternal urinary tract infection, being induced, and experiencing threatened preterm labor increase the risk of ADHD, with little gender difference, although oxytocin augmentation of labor appears protective for girls. Early term deliveries marginally increased the risk of ADHD. Studies designed to disentangle possible mechanisms, confounders, or moderators of these risk factors are warranted.

Impact of neonatal growth on IQ and behavior at early school age

OBJECTIVES

The objective was to examine associations of neonatal weight gain (NWG) and head circumference gain (HCG) with IQ scores and behavior at early school age.

METHODS

We used data from the Promotion of Breastfeeding Intervention Trial, involving Belarusian infants born full term and weighing ≥2500 g. NWG and HCG were measured as the percentage gain in weight and head circumference over the first 4 weeks relative to birth size. IQ and behavior were measured at 6.5 years of age by using the Wechsler Abbreviated Scales of Intelligence and the Strengths and Difficulties Questionnaire (SDQ), respectively, with SDQ collected from parents and teachers. The associations between the exposures (NWG, HCG) and children's IQ and SDQ were examined by using mixed models to account for clustering of measurements, and adjustment for potentially confounding perinatal and socioeconomic factors.

RESULTS

Mean NWG was 26% (SD 10%) of birth weight. In fully adjusted models, infants in the highest versus lowest quartile of NWG had 1.5-point (95% confidence interval [CI] 0.8 to 2.2) higher IQ scores (n = 13 840). A weak negative (protective) association between NWG and SDQ total difficulties scores was observed for the teacher-reported (β = -0.39, 95% CI -0.71 to -0.08, n = 12 016), but not the parent-reported (β = -0.12, 95% CI -0.39 to 0.15, n = 13 815), SDQ. Similar associations were observed with HCG and IQ and behavior.

CONCLUSIONS

Faster gains in weight or head circumference in the 4 weeks after birth may contribute to children's IQ, but reverse causality (brain function affects neonatal growth) cannot be excluded.

Preschool children with high adherence to inhaled corticosteroids for asthma do not show behavioural problems

AIM

To assess prevalence of behavioural problems in preschool children with asthma with electronically verified exposure to inhaled corticosteroids (ICS).

METHODS

Cross-sectional study of 81 children 2-5 years of age using daily ICS for persistent asthma. During 3 months' follow-up, adherence to ICS treatment was recorded by an electronical logging device (Smartinhaler(®)). Parents completed the Child Behavior Checklist 1.5-5 years (CBCL 1.5-5) to assess behavioural problems; results were compared to a published reference group of healthy children.

RESULTS

The median (interquartile range) adherence to ICS was 92 (78-97) %. There was no difference in total CBCL score between children with asthma on ICS (mean, [SD] 32.10 [1.99]) and the reference group (33.30 [1.87], 95% CI for difference -6.62 to 4.22). Children with asthma were more likely to have somatic complaints (95% CI for difference 0.64 to 1.96) and less likely to have anxious/depressive symptoms (95% CI for difference -1.57 to -0.25) than the reference group. CBCL scores were not significantly related to the electronically measured adherence rates.

CONCLUSIONS

Maintenance treatment with ICS, taken daily as prescribed, is not associated with an increased risk of behavioural problems in preschool children.