Autism risk in small- and large-for-gestational-age infants

General Movements Assessment in Infants with High Birth Weight

BACKGROUND

High birth weight (HBW) describes fetal birth weight of more than 4000 g. Infants with HBW have a high risk of developing neurological and developmental problems. Until recently, there were no studies in the literature that investigated the quality of spontaneous movements and the integrity of the developing nervous system in infants with HBW. The aims of this study were (1) to describe age-specific detailed early spontaneous movements in infants with HBW and (2) to compare the detailed early spontaneous movements of infants with HBW and normal birth weight (NBW).

METHODS

Twenty-two infants with HBW (median birth weight = 4190 g) and 22 infants with NBW (median birth weight = 3255 g) were included at 10 to 19 weeks post-term age (median = 13 weeks). All infants were assessed according to General Movement Assessment using three- to five-minute video recordings. Video recordings of each infant were evaluated using Motor Optimality Score for three- to five-month-old infants-Revised score sheet.

RESULTS

Motor Optimality Score-Revised (MOS-R) (P < 0.001), observed postural patterns (P < 0.001), and age-adequate movement repertoire (P = 0.005) were significantly lower in the infants with HBW. Infants with HBW had more aberrant (abnormal or absent) fidgety movements (18%) than those with NBW (0%).

CONCLUSIONS

The results of this study demonstrated that the motor repertoire of infants with HBW tended to decrease more than that of those with NBW. To enable the follow-up of progression as a result of these assessments infants in need should be referred to age-adequate early intervention programs.

Obstetrical and neonatal outcomes after vitrified-warmed blastocyst transfer in day 1 rescue intracytoplasmic sperm injection cycles: a retrospective cohort study

BACKGROUND

Fertilization failure often occurs in conventional IVF cycles, and day 1 rescue ICSI is frequently recommended. In this study, the effect of rescue ICSI on obstetrical and neonatal outcomes after a single blastocyst transfer in vitrified-warmed cycles is evaluated.

METHODS

This cohort study was a retrospective analysis of 703 vitrified-warmed single blastocyst transfers and 219 singletons in the r-ICSI group compared with 11,611 vitrified-warmed single blastocyst transfers in the IVF/ICSI and 4472 singletons in the IVF/ICSI group, respectively, and patients just undergoing their first IVF treatments were included in this study. Pregnancy rate (PR), live birth rate (LBR), and singleton birthweight were the primary outcome measures. Multiple linear regression analysis and logistic regression analysis were performed to evaluate the possible relationship between obstetrical and neonatal outcomes and fertilization method (including IVF, ICSI, and r-ICSI) after adjusting for other potential confounding factors.

RESULTS

PR and the LBR were lower in the r-ICSI group compared with the IVF/ ICSI group. Singletons from the r-ICSI group had a higher Z-score and the proportion of large for gestational age (LGA) newborns was greater compared with singletons from the IVF/ICSI group.

CONCLUSION

The results of the study indicated that a 31% LBR after r-ICSI is acceptable for vitrified-warmed blastocyst transfer, but the safety of transfer is a concern because of the lower PR and LBR compared with IVF/ICSI. The safety of r-ICSI newborns is also a concern because of the significantly higher birthweight and the proportion of LGA in r-ICSI group newborns compared with the IVF/ICSI group.

The effect of an extended culture period on birth weight among singletons born after single or double vitrified embryo transfer

Aim

To evaluate the effect of an extended culture period on birth weight among singletons born after vitrified-warmed embryo transfer.

Methods

A retrospective cohort study was performed among 12400 women who gave birth to 1015, 1027, 687, and 9671 singletons after single blastocyst transfer, single cleavage-stage embryo transfer, double blastocyst transfer, and double cleavage-stage embryo transfer, respectively.

Results

The unadjusted birth weight of singletons born after vitrified blastocyst transfer were heavier than those born after cleavage-stage transfer (β=30.28, SE=13.17, P=0.022), as were the adjusted birth weights (β=0.09, SE=0.03, P=0.007). In addition, there was a 37% increased odd of having an infant with high birth weight after vitrified blastocyst transfer compared with vitrified cleavage stage transfer (OR=1.37, 95% CI:1.07-1.77).

Conclusion

The unadjusted and adjusted birth weight and odds of having an infant with high birth weight significantly increased after blastocyst transfer compared with cleavage-stage embryo transfer in vitrified-warmed cycles.

Association between interpregnancy interval and risk of autism spectrum disorder: a systematic review and Bayesian network meta-analysis

Although the risk of autism spectrum disorder (ASD) has been reported to be associated with interpregnancy intervals (IPIs), their association remains debatable due to inconsistent findings in existing studies. Therefore, the present study aimed to explore their association. PubMed, Embase, Web of Science, and the Cochrane Library were systematically retrieved up to May 25, 2022. An updated search was performed on May 25, 2023, to encompass recent studies. The quality of the included studies was assessed using the Newcastle-Ottawa Scale (NOS). Our primary outcome measures were expressed as adjusted odds ratios (ORs). Given various control measures for IPI and diverse IPI thresholds in the included studies, a Bayesian network meta-analysis was performed. Eight studies were included, involving 24,865 children with ASD and 2,890,289 children without ASD. Compared to an IPI of 24 to 35 months, various IPIs were significantly associated with a higher risk of ASD (IPIs < 6 months: OR = 1.63, 95% CI 1.53-1.74, n = 5; IPIs of 6-11 months: OR = 1.50, 95% CI 1.42-1.59, n = 4; IPIs of 12-23 months: OR = 1.19, 95% CI 1.12-1.23, n = 10; IPIs of 36-59 months: OR = 0.96, 95% CI 0.94-0.99, n = 2; IPIs of 60-119 months: OR = 1.15, 95% CI 1.10-1.20, n = 4; IPIs > 120 months: OR = 1.57, 95% CI 1.43-1.72, n = 4). After adjusting confounding variables, our analysis delineated a U-shaped restricted cubic spline curve, underscoring that both substantially short (< 24 months) and excessively long IPIs (> 72 months) are significantly correlated with an increased risk of ASD.  Conclusion: Our analysis indicates that both shorter and longer IPIs might predispose children to a higher risk of ASD. Optimal childbearing health and neurodevelopmental outcomes appear to be associated with a moderate IPI, specifically between 36 and 60 months. What is Known: • An association between autism spectrum disorder (ASD) and interpregnancy intervals (IPIs) has been speculated in some reports. • This association remains debatable due to inconsistent findings in available studies. What is New: • Our study delineated a U-shaped restricted cubic spline curve, suggesting that both shorter and longer IPIs predispose children to a higher risk of ASD. • Optimal childbearing health and neurodevelopmental outcomes appear to be associated with a moderate IPI, specifically between 36 and 60 months.

Environmental Risk Factors in Autism Spectrum Disorder: A Narrative Review

Existing evidence indicates that environmental factors might contribute up to 50% of the variance in autism spectrum disorder (ASD) risk. This structured narrative review offers a comprehensive synthesis of current knowledge on environmental risk factors in ASD, including evaluation of conflicting evidence, exploration of underlying mechanisms, and suggestions for future research directions. Analysis of diverse epidemiological investigations indicates that certain environmental factors, including advanced parental age, preterm birth, delivery complications, and exposure to toxic metals, drugs, air pollutants, and endocrine-disrupting chemicals, are linked to an increased ASD risk through various mechanisms such as oxidative stress, inflammation, hypoxia, and its consequences, changes in neurotransmitters, disruption of signaling pathways and some others. On the other hand, pregnancy-related factors such as maternal diabetes, maternal obesity, and caesarian section show a weaker association with ASD risk. At the same time, other environmental factors, such as vaccination, maternal smoking, or alcohol consumption, are not linked to the risk of ASD. Regarding nutritional elements data are inconclusive. These findings highlight the significance of environmental factors in ASD etiology and emphasize that more focused research is needed to target the risk factors of ASD. Environmental interventions targeting modifiable risk factors might offer promising avenues for ASD prevention and treatment.

[Neuropsychological development of large for gestational age infants at the age of 12 months]

OBJECTIVES

To investigate the level of neuropsychological development in large for gestational age (LGA) infants at the age of 12 months.

METHODS

The infants, aged 12 to <13 months, who attended the Outpatient Service of Child Care in the First Affiliated Hospital of Shandong First Medical University from December 2021 to June 2023, were enrolled as subjects. According to the gestational age and birth weight, they were divided into preterm appropriate for gestational age (AGA) group, preterm LGA group, early term AGA group, early term LGA group, full-term AGA group, and full-term LGA group. A modified Poisson regression analysis was used to investigate the association between LGA and neuropsychological development outcome at 12 months of age.

RESULTS

After adjustment for confounding factors, compared with the full-term AGA group at the age of 12 months, the full-term LGA group had a significant increase in the risk of language deficit (RR=1.364, 95%CI: 1.063-1.750), the early term LGA group had significant increases in the risk of abnormal gross motor, fine motor, language, and the preterm LGA group had significant increases in the risk of abnormal language, social behavior, and total developmental quotient (P<0.05); also, the early term AGA group had higher risks of developmental delay across all five attributes and in total developmental quotient at the age of 12 months (P<0.05); except for the language attribute, the preterm AGA group had higher risks of developmental delay in the other 4 attributes (P<0.05).

CONCLUSIONS

The neuropsychological development of LGA infants with different gestational ages lags behind that of full-term AGA infants at 12 months of age, and follow-up and early intervention of such infants should be taken seriously in clinical practice.

The early life growth of head circumference, weight, and height in infants with autism spectrum disorders: a systematic review

BACKGROUNDS

The Autism spectrum disorder (ASD) prevalence has increased significantly over the past two decades. This review summarizes the current knowledge of the association between the early life growth of head circumference (HC), weight, and height with ASD in infants.

METHODS

PubMed, Scopus, Science Direct, and Google Scholar databases were searched up to November 2021 using relevant keywords. All original articles are written in English evaluating the early life growth of HC, weight, and height in infants with ASD were eligible for the present review.

RESULTS

Totally, 23 articles involving 4959 infants were included in this review. Of 13 studies that evaluated HC of infants at birth, 10 studies (83.33%) showed that the HC at the birth of autistic children was similar to that of the average found in the control group. Among 21 studies that evaluated the HC and weight status in infants, 19 studies (90.47%) showed that autistic children had larger HC and weight than the control group or abnormal acceleration of head growth during infancy. Height growth of infants was investigated in 13 studies, of which 10 cases (76.92%) reported that infants with ASD were significantly longer than control groups. Most of he included studies had a good quality.

CONCLUSIONS

The findings suggest that in infants with ASD, without the contribution of birth growth factors and sex of the child, the growth of HC, weight, and height probably was faster than in infants with normal development, in early life. Therefore, these measurements might be useful as initial predictive biomarkers for the risk of developing ASD.

Paternal lipopolysaccharide exposure induced intrauterine growth restriction via the inactivation of placental MEST/PI3K/AKT pathway in mice

Maternal lipopolysaccharide (LPS) exposure during pregnancy has been related to IUGR. Here, we explored whether paternal LPS exposure before mating impaired fetal development. All male mice except controls were intraperitoneally injected with LPS every other day for a total of five injections. The next day after the last LPS, male mice were mated with untreated female mice. Interestingly, fetal weight and crown-rump length were reduced, while the incidence of IUGR was increased in paternal LPS exposure group. Additionally, paternal LPS exposure leaded to poor placental development through causing cell proliferation inhibition and apoptosis. Additional experiment demonstrated that the inactivation of placental PI3K/AKT pathway might be involved in paternal LPS-induced cell proliferation inhibition and apoptosis of trophoblast cells. Furthermore, the mRNA and protein levels of mesoderm specific transcript (MEST), a maternally imprinted gene with paternal expression, were significantly decreased in mouse placentas from paternal LPS exposure. Further analysis showed that paternal LPS exposure caused the inactivation of placental PI3K/AKT pathway and then cell proliferation inhibition and apoptosis might be via down-regulating placental MEST. Overall, our results provide evidence that paternal LPS exposure causes poor placental development and subsequently IUGR may be via down-regulating MEST/PI3K/AKT pathway, and then inducing cell proliferation inhibition and apoptosis in placentas.

Early childhood parent-reported speech problems in small and large for gestational age term-born and preterm-born infants: a cohort study

OBJECTIVE

(1) To assess if preterm and term small for gestational age (SGA) or large for gestational age (LGA) infants have more parent-reported speech problems in early childhood compared with infants with birth weights appropriate for gestational age (AGA). (2) To assess if preterm and term SGA and LGA infants have more parent-reported learning, behavioural, hearing, movement and hand problems in early childhood compared with AGA infants.

DESIGN

Cohort study.

SETTING

Wales, UK.

PARTICIPANTS

7004 children with neurodevelopmental outcomes from the Respiratory and Neurological Outcomes of Children Born Preterm Study which enrolled 7129 children, born from 23 weeks of gestation onwards, to mothers aged 18-50 years of age were included in the analysis.

OUTCOME MEASURES

Parent-reported single-answer questionnaires were completed in 2013 to assess early childhood neurodevelopmental outcomes. The primary outcome was parent-reported speech problems in early childhood adjusted for clinical and demographic confounders in SGA and LGA infants compared with AGA infants. Secondary outcomes measured were parent-reported early childhood learning, behavioural, hearing, movement and hand problems.

RESULTS

Median age at the time of study was 5 years, range 2-10 years. Although the adjusted OR was 1.19 (0.92 to 1.55) for SGA infants and OR 1.11 (0.88 to 1.41) for LGA infants, this failed to reach statistical significance that these subgroups were more likely to have parent-reported speech problems in early childhood compared with AGA infants. This study also found parent-reported evidence suggestive of potential learning difficulties in early childhood (OR 1.51 (1.13 to 2.02)) and behavioural problems (OR 1.35 (1.01 to 1.79)) in SGA infants.

CONCLUSION

This study of 7004 infants in Wales suggests that infants born SGA or LGA likely do not have higher risks of parent-reported speech problems in early childhood compared with infants born AGA. To further ascertain this finding, studies with wider population coverage and longer-term follow-up would be needed.

Predictors of autism spectrum disorder diagnosis in a spanish sample of preterm children with very low birthweight: A cross-sectional study

Background and Aims

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with a higher likelihood of being diagnosed in preterm populations. Likewise, low birthweight has also been connected with an increased likelihood of ASD. The objectives were to study the frequency and define the relationship between ASD, gestational age, birthweight, and growth percentiles for preterm children.

Methods

A sample of preterm children with very low birthweight was selected from the Spanish population at 7-10 years old. Families were contacted from the hospital, and they were offered an appointment to conduct a neuropsychological assessment. The children who showed signs of ASD were referred to the diagnostic unit for differential diagnosis.

Results

A total of 57 children completed full assessments, with 4 confirmed ASD diagnoses. The estimated prevalence was 7.02%. There were statistically significant weak correlations between ASD and gestational age (τb = -0.23), and birthweight (τb = -0.25), suggesting there is a higher likelihood of developing ASD for those born smaller or earlier in their gestation.

Conclusion

These results could improve ASD detection and outcomes for this vulnerable population while also supporting and enhancing previous findings.

Associations of preterm and early-term birth with suspected developmental coordination disorder: a national retrospective cohort study in children aged 3-10 years

BACKGROUND

This study analyzed the motor development and suspected developmental coordination disorder of very and moderately preterm (< 34+0 gestational age), late preterm (34+0-36+6 gestational week), and early-term (37+0-38+6 gestational week) children compared to their full-term peers with a national population-based sample in China.

METHODS

A total of 1673 children (799 girls, 874 boys) aged 3-10 years old were individually assessed with the Movement Assessment Battery for Children-second edition (MABC-2). The association between gestational age and motor performance of children was analyzed using a multilevel regression model.

RESULTS

The global motor performance [β =  - 5.111, 95% confidence interval (CI) =  - 9.200 to - 1.022; P = 0.015] and balance (β =  - 5.182, 95% CI =  - 5.055 to - 1.158; P = 0.003) for very and moderately preterm children aged 3-6 years old were significantly lower than their full-term peers when adjusting for confounders. Late preterm and early-term children showed no difference. Moreover, very and moderately preterm children aged 3-6 years had a higher risk of suspected developmental coordination disorder (DCD) (≤ 5 percentile of MABC-2 score) when adjusting for potential confounders [odds ratio (OR) = 2.931, 95% CI = 1.067-8.054; P = 0.038]. Late preterm and early-term children showed no difference in motor performance from their full-term peers (each P > 0.05).

CONCLUSIONS

Our findings have important implications for understanding motor impairment in children born at different gestational ages. Very and moderately preterm preschoolers have an increased risk of DCD, and long-term follow-up should be provided for early detection and intervention.

Speech-Encoding Deficits in Neonates Born Large-for-Gestational Age as Revealed With the Envelope Frequency-Following Response

OBJECTIVES

The present envelope frequency-following response (FFRENV) study aimed at characterizing the neural encoding of the fundamental frequency of speech sounds in neonates born at the higher end of the birth weight continuum (>90th percentile), known as large-for-gestational age (LGA).

DESIGN

Twenty-five LGA newborns were recruited from the maternity unit of Sant Joan de Déu Barcelona Children's Hospital and paired by age and sex with 25 babies born adequate-for-gestational age (AGA), all from healthy mothers and normal pregnancies. FFRENVs were elicited to the/da/ syllable and recorded while the baby was sleeping in its cradle after a successful universal hearing screening. Neural encoding of the stimulus' envelope of the fundamental frequency (F0ENV) was characterized through the FFRENV spectral amplitude. Relationships between electrophysiological parameters and maternal/neonatal variables that may condition neonatal neurodevelopment were assessed, including pregestational body mass index (BMI), maternal gestational weight gain and neonatal BMI.

RESULTS

LGA newborns showed smaller spectral amplitudes at the F0ENV compared to the AGA group. Significant negative correlations were found between neonatal BMI and the spectral amplitude at the F0ENV.

CONCLUSIONS

Our results indicate that in spite of having a healthy pregnancy, LGA neonates' central auditory system is impaired in encoding a fundamental aspect of the speech sounds, namely their fundamental frequency. The negative correlation between the neonates' BMI and FFRENV indicates that this impaired encoding is independent of the pregnant woman BMI and weight gain during pregnancy, supporting the role of the neonatal BMI. We suggest that the higher adipose tissue observed in the LGA group may impair, via proinflammatory products, the fine-grained central auditory system microstructure required for the neural encoding of the fundamental frequency of speech sounds.

Prenatal environment and developmental trajectories: the intrauterine growth restriction

The prenatal environment is of fundamental importance for the fetus, as the fetus is particularly susceptible to environmental influences while in utero, and several prenatal adversities may constitute a risk factor for fetal growth and child development. Intrauterine growth restriction (IUGR) refers to a pregnancy complication involving the inadequate growth of the fetus in utero, with potential programming consequences on the children's brain-behavior development. In this narrative review we will discuss the most recent literature about IUGR children, including their development and their relationship with the prenatal and postnatal environment. In particular, as an attempt to an adaptive response to intrauterine changes, the brain development of IUGR fetuses follows abnormal developmental pathways, which likely has cascade effects on the future neurodevelopmental outcomes of the children. Cognitive and motor functions are in fact impaired, as well as IUGR children present, across studies, poor socio-emotional abilities and a greater risk for internalizing and externalizing behavior problems. The current work also highlights how the postnatal environment, and in particular parental care, has an important role in IUGR development, acting as a protective factor, or otherwise increasing their constitutional vulnerabilities. Overall, this narrative review has important implications for clinical practice, suggesting the need for long-term follow-up care with IUGR children and strategies supporting parent-child interactions as well.

The Association between Threatened Abortion and the Risk of Autism Spectrum Disorders among Children: A Meta-Analysis

Background

The current study is aimed at updating the observational studies on the relationship between threatened abortion and the risk of ASD.

Methods

The search keywords were covered in three electronic databases PubMed, Web of Science, and Scopus up to April 2022. The modified Newcastle-Ottawa scale (NOS) was applied to detect the quality of epidemiological studies. We used the chi-square test and the I ² statistic to show the heterogeneity among articles. I ² more than 50% was considered high heterogeneity. Egger's and Begg's line regression tests were used for evaluating the publication bias. The random-effects model was applied for the analysis of the findings. The Stata 13.0 software package was applied for analysis and indicated p value less than 0.05 as a significant level.

Results

The pooled analysis reported significant differences between threatened abortion and the risk of ASD in adjusted studies (OR = 1.93; 95% CI: 1.12, 2.73; I ² = 59.5.0%) and in crude studies (OR = 2.17; 95% CI: 1.46, 2.88; I ² = 39.5%). The evidence of publication bias was not found.

Conclusions

The findings suggest that threatened abortion is a risk factor for ASD. As a result, screening tools to detect are necessary in mothers facing a threatened abortion.

Association of birthweight centiles and early childhood development of singleton infants born from 37 weeks of gestation in Scotland: A population-based cohort study

BACKGROUND

Birthweight centiles beyond the traditional thresholds for small or large babies are associated with adverse perinatal outcomes but there is a paucity of data about the relationship between birthweight centiles and childhood development among children born from 37 weeks of gestation. This study aims to establish the association between birthweight centiles across the whole distribution and early childhood development among children born from 37 weeks of gestation.

METHODS AND FINDINGS

This is a population-based cohort study of 686,284 singleton infants born from 37 weeks of gestation. The cohort was generated by linking pregnancy and delivery data from the Scottish Morbidity Records (2003 to 2015) and the child developmental assessment at age 2 to 3.5 years. The main outcomes were child's fine motor, gross motor, communication, and social developmental concerns measured with the Ages and Stages Questionnaires-3 (ASQ-3) and Ages and Stages Questionnaire: Social & Emotional-2 (ASQ:SE-2), and for a subset of children with additional specialist tools such as the Modified Checklist for Autism in Toddlers (M-CHAT) if the ASQ3/SE indicate these are necessary. The ASQ score for each domain was categorised as "concern" and "no concern." We used multivariate cubic regression splines to model the associations between birthweight centiles and early childhood developmental concerns. We used multivariate Poisson regression models, with cluster robust errors, to estimate the relative risks (RRs) of developmental concerns below and above the established thresholds. We adjusted for maternal age, early pregnancy body mass index (BMI), parity, year of delivery, gestational age at delivery, smoking history, substance misuse in pregnancy, alcohol intake, ethnicity, residential area deprivation index, maternal clinical conditions in pregnancy (such as diabetes and pre-eclampsia), induction of labour, and child's sex. Babies born from 37 weeks of gestation with birthweight below the 25th centile, compared to those between the 25th and 74th centile, were at higher risk of developmental concerns. Those born between the 10th and 24th centile had an RR of 1.07 (95% CI: 1.03 to 1.12, p < 0.001), between the 3rd and 9th centile had an RR: 1.18 (95% CI: 1.12 to 1.25, p < 0.001), and <3rd centile had an RR of 1.37 (95% CI: 1.24 to 1.50, p < 0.001). There was no substantial increase in the risk of early childhood developmental concerns for larger birthweight categories of 75th to 89th (RR: 1.01; 95% CI: 0.97 to 1.05; p = 0.56), 90th to 96th (RR: 0.99; 95% CI: 0.94 to 1.05; p = 0.86), and ≥97th centiles (RR: 1.04; 95% CI: 0.97 to 1.12; p = 0.27), referent to birthweight between 25th and 74th centile. The percentage of developmental concerns attributable to birthweight between the 10th and 24th centile was more than that of birthweight <3rd centile (p = 0.023) because this group includes more of the population. Approximately 2.50% (95% CI: 1.26 to 3.61) of social skills concerns and 3.00% (95% CI: 1.33 to 4.67) of fine motor developmental concerns were attributable to birthweight between the 10th and 24th centile compared to 0.90% (95% CI: 0.48 to 1.26) and 2.30% (95% CI: 1.73 to 2.67) respectively for birthweight <3rd centile. We acknowledge the limitation of ASQ as a screening tool, the subjective nature of developmental assessments (particularly for speech) among young children, and inability to control for early childhood illness and upbringing factors may have an impact on our findings.

CONCLUSIONS

We observed that from 37 weeks of gestation birthweight below the 25th centile was associated with child developmental concerns, with an association apparent at higher centiles above the conventional threshold defining small for gestational age (SGA, 3rd or 10th centile). Mild to moderate SGA is an unrecognised potentially important contributor to the prevalence of developmental concerns. Closer surveillance, appropriate parental counselling, and increased support during childhood may reduce the risks associated with lower birthweight centiles.

Cell-type-specific epigenetic effects of early life stress on the brain

Early life stress (ELS) induces long-term phenotypic adaptations that contribute to increased vulnerability to a host of neuropsychiatric disorders. Epigenetic mechanisms, including DNA methylation, histone modifications and non-coding RNA, are a proposed link between environmental stressors, alterations in gene expression, and phenotypes. Epigenetic modifications play a primary role in shaping functional differences between cell types and can be modified by environmental perturbations, especially in early development. Together with contributions from genetic variation, epigenetic mechanisms orchestrate patterns of gene expression within specific cell types that contribute to phenotypic variation between individuals. To date, many studies have provided insights into epigenetic changes resulting from ELS. However, most of these studies have examined heterogenous brain tissue, despite evidence of cell-type-specific epigenetic modifications in phenotypes associated with ELS. In this review, we focus on rodent and human studies that have examined epigenetic modifications induced by ELS in select cell types isolated from the brain or associated with genes that have cell-type-restricted expression in neurons, microglia, astrocytes, and oligodendrocytes. Although significant challenges remain, future studies using these approaches can enable important mechanistic insight into the role of epigenetic variation in the effects of ELS on brain function.

Defective placentation syndromes and autism spectrum disorder in the offspring: population-based cohort and sibling-controlled studies

Defective placentation underlies diverse syndromic manifestations that could affect brain development including: (1) placental abruption, (2) term preeclampsia with a small-for-gestational age (SGA) infant, (3) preterm preeclampsia, and (4) spontaneous preterm birth. We investigated the relations between these defective placentation syndromes and the incidence of Autism Spectrum Disorder (ASD) in offspring. We conducted a population-based cohort study of 1,645,455 non-malformed singleton infants born in Sweden 2000-2016 who were followed for up to 17 years using national registers. We compared ASD rates for children prenatally exposed and unexposed to defective placentation syndromes with use of adjusted hazard ratios (HR) with 95% confidence intervals (CI) from Cox regression. We also conducted sibling-controlled analyses among 1,092,132 full siblings. The association of the syndromes with ASD independent of preterm birth was estimated in mediation analyses. There were 23,810 cases of ASD. In both general cohort and sibling analyses, adjusted HRs (95% CI) of ASD were increased in children of mothers with term preeclampsia combined with SGA [1.5 (1.3, 1.9) and 1.9 (1.1, 3.3), respectively], preterm preeclampsia < 34 weeks [1.8 (1.4, 2.2) and 4.2 (2.1, 8.5), respectively], and spontaneous very or extremely preterm birth (≤ 31 weeks) [2.6 (2.2, 3.0) and 2.4 (1.5, 3.8), respectively]. Placental abruption was associated with increased HR of ASD in general cohort analysis only. The association between preeclampsia and ASD was not fully explained by preterm birth. In conclusion, syndromes linked to defective placentation are associated with increased incidence of ASD in the offspring.

Combined exposure to maternal high-fat diet and neonatal lipopolysaccharide disrupts stress-related signaling but normalizes spatial memory in juvenile rats

Both neonatal infections and exposure to maternal obesity are inflammatory stressors in early life linked to increased rates of psychopathologies related to mood and cognition. Epidemiological studies indicate that neonates born to mothers with obesity have a higher likelihood of developing neonatal infections, however effects on offspring physiology and behavior resulting from the combination of these stressors have yet to be investigated. The aim of this study was to explore immediate and persistent phenotypes resulting from neonatal lipopolysaccharide (nLPS) administration in rat offspring born to dams consuming a high-fat diet (HFD). Neural transcript abundance of genes involved with stress regulation and spatial memory were examined alongside related behaviors. At the juvenile age point, unlike offspring exposed to maternal HFD (mHFD) or nLPS alone, offspring with combined exposure to mHFD + nLPS displayed altered transcript abundances of stress-related genes in the ventral hippocampus (HPC) in a manner conducive to potentiating stress responses. For memory-related phenotypes, juveniles exposed to mHFD + nLPS exhibited normalized spatial memory and levels of memory-related gene expression in the dorsal HPC similar to control diet offspring, while control diet + nLPS, and mHFD offspring exhibited reduced levels of memory-related gene expression and impaired spatial memory. These findings suggest that dual exposure to unique inflammatory stressors in early life can disrupt neural stress regulation but normalize spatial memory processes.

Association between small for gestational age and risk of autism spectrum disorders: a meta-analysis

BACKGROUND

The relationship between small for gestational age (SGA) and autism spectrum disorders (ASDs) remains unknown.

PURPOSE

This meta-analysis aimed to investigate the relationship between SGA and the risk of ASD.

METHODS

We searched PubMed, Web of Science, and Scopus databases from inception to November 2020. The heterogeneity across studies was explored using the I2 statistic. The possibility of publication bias was assessed using Begg test. The results were reported using the odds ratio (OR) and 95% confidence interval (CI) using a random-effects model.

RESULTS

The literature search yielded 824 articles with 8,752,138 participants. We assessed the association between SGA and the risk of ASD in cohort and case-control studies. Based on the random-effects model, compared with SGA, the estimated OR of the risk of ASD was 1.17 (95% CI, 1.09-1.24). Therefore, there was a significant association between SGA and the risk of ASD.

CONCLUSION

Based on OR reports in epidemiological studies, we showed that SGA is a risk factor for and can increase the risk of ASD. The association between SGA and ASD risk has further relevance to the current public health emphasis on appropriate prepregnancy weight and pregnancy weight gain.

Parental Feeding Practices and Child-Related Factors are Associated with Overweight and Obesity in Children and Adolescents with Autism Spectrum Disorder

Atypical eating behaviors displayed by children with autism spectrum disorder (ASD) predispose them to unhealthy weight gain. We determined the factors associated with body weight status among 261 children with ASD (3-18 years) at nine autism intervention centers. Their mothers completed a self-administered questionnaire on sociodemographic background, parenting style, parental feeding practices, parenting stress, sleep habits, eating behaviors, and autism severity. Children with older age, non-full term gestational age, high maternal perceived weight, high maternal concern about child weight, and low pressure to eat were more likely to be overweight and obese. Obesity is a major concern among children with ASD. Healthy weight management programs for parents should incorporate appropriate feeding practices and a healthy perception of body weight.

Is meconium exposure associated with autism spectrum disorders in children?

BACKGROUND

The results differ among published studies regarding exposure to meconium and the risk of developing autism spectrum disorders (ASDs).

PURPOSE

The present study pooled all of the epidemiologic studies retrieved from broader databases on the association between meconium exposure and risk of developing ASD in children.

METHODS

The Web of Science, PubMed, Scopus, and Google Scholar databases were searched without language restrictions for articles published between their inception to February 20, 2020, using relevant keywords. The pooled odds ratios (ORs) and their 95% confidence intervals (CIs) were calculated as random-effect estimates of the associations among studies. A subgroup analysis was conducted to explore any potential sources of heterogeneity among studies.

RESULTS

The pooled estimate of OR reported a weakly significant association between meconium exposure and ASD development in children (OR, 1.13; 95% CI, 1.03-1.24). There was low heterogeneity among the articles reporting risk for ASD among children (I2=19.3%; P=0.259). The results of subgroup analysis based on meconium exposure showed a significant association between a meconium-stained neonate and ASD development (OR, 1.18; 95% CI, 1.11-1.24).

CONCLUSION

Meconium exposure was weakly associated with an increased risk of ASD. However, more evidence based on large prospective cohort studies is required to provide conclusive evidence about whether meconium exposure is associated with an increased risk of ASD development.

The association between gestational diabetes and ASD and ADHD: a systematic review and meta-analysis

There is growing evidence for a role of maternal diabetes in the pathogenesis of neurodevelopmental disorders. However, the specific association between gestational diabetes (GDM), as opposed to pre-gestational diabetes, has been poorly isolated. Thus the aim was to systematically review and meta-analyse literature pertaining to prevalence and risk for two neurodevelopmental disorders: autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD), when exposed to GDM. PubMed, Cochrane Library, EMBASE, PsycINFO and CINAHL were systematically searched for eligible literature, with forward and backward citation tracking. Screening for eligibility, risk of bias assessment and data extraction were performed by two independent reviewers. 18 studies measuring ASD and 15 measuring ADHD met inclusion criteria. On meta-analysis there was an increased risk of ASD (OR 1.42; 95% CI 1.22, 1.65) but not ADHD (OR 1.01; 95% CI 0.79, 1.28). We discuss potential mechanisms for these differing risks. Greater understanding of risk factors, including GDM, for these neurodevelopmental disorders and potential mechanisms may help inform strategies aimed at prevention of exposure to these adversities during pregnancy.

Perinatal Factors in Newborn Are Insidious Risk Factors for Childhood Autism Spectrum Disorders: A Population-based Study

We analyzed claims data from the Taiwan National Health Insurance database, which contains data of 23.5 million Taiwan residents. We included children born after January 1, 2000 who had received a diagnosis of autism spectrum disorders (ASD). Patients who were not diagnosed with ASD were included in the control group. The ASD prevalence was 517 in 62,051 (0.83%) children. Neonatal jaundice, hypoglycemia, intrauterine growth retardation (IUGR), and craniofacial anomalies (CFA) differed significantly between the ASD and control groups. After logistic regressive analysis, the adjusted odds ratios of IUGR, CFA, neonatal hypoglycemia, and neonatal jaundice were 8.58, 7.37, 3.83, and 1.32, respectively. Those insidiously perinatal risk factors, namely CFA, IUGR, neonatal hypoglycemia, and neonatal jaundice, could increase the risk of ASD.

Autism Spectrum Disorders in Children Exposed in Utero to Hyperemesis Gravidarum

OBJECTIVE

This study aimed to determine if hyperemesis gravidarum (HG) is associated with autism spectrum disorder (ASD) risk, and how this association is influenced by race, ethnicity, sex, exposure timing, and medication used to treat it.

STUDY DESIGN

This is a retrospective cohort study using records from 469,789 mother-child pairs who delivered at Kaiser Permanente Southern California (KPSC) hospital (1991-2014). Singleton-born children were followed longitudinally from 2 to 17 years of age. Clinical records were used to determine the diagnosis of HG and specialist-confirmed diagnosis of ASD.

RESULTS

Children exposed to HG in-utero had higher rates of ASD than unexposed children (2.87 vs. 1.71/1,000 person-years; adjusted hazard ratio [adj.HR]: 1.53; 95% confidence interval [CI]: 1.37-1.70). Children exposed at first and second trimester of pregnancies were more likely to develop ASD; 1.58-fold (95% CI: 1.40-1.79), and 1.36-fold (95% CI: 1.05-1.75), respectively, compared with unexposed children. HG was associated with ASD for boys (adj.HR: 1.50; 95% CI: 1.33-1.70) and girls (adj.HR: 1.62; 95% CI: 1.28-2.05). HG was significantly associated with ASD risk in white and Hispanic children. The medications used to treat HG did not contribute to ASD risk.

CONCLUSION

HG diagnosis is associated with ASD risk and may be helpful in identifying at-risk children who could benefit from enhanced surveillance and earlier diagnosis and intervention.

The Prenatal Hormone Milieu in Autism Spectrum Disorder

Though the etiology of autism spectrum disorder (ASD) remains largely unknown, recent findings suggest that hormone dysregulation within the prenatal environment, in conjunction with genetic factors, may alter fetal neurodevelopment. Early emphasis has been placed on the potential role of in utero exposure to androgens, particularly testosterone, to theorize ASD as the manifestation of an "extreme male brain." The relationship between autism risk and obstetric conditions associated with inflammation and steroid dysregulation merits a much broader understanding of the in utero steroid environment and its potential influence on fetal neuroendocrine development. The exploration of hormone dysregulation in the prenatal environment and ASD development builds upon prior research publishing associations with obstetric conditions and ASD risk. The insight gained may be applied to the development of chronic adult metabolic diseases that share prenatal risk factors with ASD. Future research directions will also be discussed.

The Association Between High Birth Weight and Long-Term Outcomes-Implications for Assisted Reproductive Technologies: A Systematic Review and Meta-Analysis

Background: Studies have shown that the prevalence of children born with high birth weight or large for gestational age (LGA) is increasing. This is true for spontaneous pregnancies; however, children born after frozen embryo transfer (FET) as part of assisted reproductive technology (ART) also have an elevated risk. In recent years, the practice of FET has increased rapidly and while the perinatal and obstetric risks are well-studied, less is known about the long-term health consequences. Objective: The aim of this systematic review was to describe the association between high birth weight and LGA on long-term child outcomes. Data Sources: PubMed, Scopus, and Web of Science were searched up to January 2021. Exposure included high birth weight and LGA. Long-term outcome variables included malignancies, psychiatric disorders, cardiovascular disease, and diabetes. Study Selection: Original studies published in English or Scandinavian languages were included. Studies with a control group were included while studies published as abstracts and case reports were excluded. Data Extraction: The methodological quality, in terms of risk of bias, was assessed by pairs of reviewers. Robins-I (www.methods.cochrane.org) was used for risk of bias assessment in original articles. For systematic reviews, AMSTAR (www.amstar.ca) was used. For certainty of evidence, we used the GRADE system. The systematic review followed PRISMA guidelines. When possible, meta-analyses were performed. Results: The search included 11,767 articles out of which 173 met the inclusion criteria and were included in the qualitative analysis, while 63 were included in quantitative synthesis (meta-analyses). High birth weight and/or LGA was associated with low to moderately elevated risks for certain malignancies in childhood, breast cancer, several psychiatric disorders, hypertension in childhood, and type 1 and 2 diabetes. Conclusions: Although the increased risks for adverse outcome in offspring associated with high birth weight and LGA represent serious health effects in childhood and in adulthood, the size of these effects seems moderate. The identified risk association should, however, be taken into account in decisions concerning fresh and frozen ART cycles and is of general importance in view of the increasing prevalence in high birthweight babies.

Gestational age and the risk of autism spectrum disorder in Sweden, Finland, and Norway: A cohort study

INTRODUCTION

The complex etiology of autism spectrum disorder (ASD) is still unresolved. Preterm birth (<37 weeks of gestation) and its complications are the leading cause of death of babies in the world, and those who survive often have long-term health problems. Length of gestation, including preterm birth, has been linked to ASD risk, but robust estimates for the whole range of gestational ages (GAs) are lacking. The primary objective of this study was to provide a detailed and robust description of ASD risk across the entire range of GAs while adjusting for sex and size for GA.

METHODS AND FINDINGS

Our study had a multinational cohort design, using population-based data from medical registries in three Nordic countries: Sweden, Finland, and Norway. GA was estimated in whole weeks based on ultrasound. Children were prospectively followed from birth for clinical diagnosis of ASD. Relative risk (RR) of ASD was estimated using log-binomial regression. Analyses were also stratified by sex and by size for GA. The study included 3,526,174 singletons born 1995 to 2015, including 50,816 (1.44%) individuals with ASD. In the whole cohort, 165,845 (4.7%) were born preterm. RR of ASD increased by GA, from 40 to 24 weeks and from 40 to 44 weeks of gestation. The RR of ASD in children born in weeks 22-31, 32-36, and 43-44 compared to weeks 37-42 were estimated at 2.31 (95% confidence interval [CI] 2.15-2.48; 1.67% vs 0.83%; p-value < 0.001), 1.35 (95% CI 1.30-1.40; 1.08% vs 0.83%; p-value < 0.001), and 1.37 (95% CI 1.21-1.54; 1.74% vs 0.83%; p-value < 0.001), respectively. The main limitation of this study is the lack of data on potential causes of pre- or postterm birth. Also, the possibility of residual confounding should be considered.

CONCLUSION

In the current study, we observed that the RR of ASD increased weekly as the date of delivery diverged from 40 weeks, both pre- and postterm, independently of sex and size for GA. Given the unknown etiology of ASD and the lifelong consequences of the disorder, identifying groups of increased risk associated with a potentially modifiable risk factor is important.

Continuous association of total bile acid levels with the risk of small for gestational age infants

The association between maternal serum total bile acid (TBA) levels and small-for-gestational-age (SGA) infants is unclear. We investigated the association between various degrees of serum TBA levels and the risk of SGA infants in a Chinese population. The current study performed a cohort study among 11811 mothers with singleton pregnancy. Subjects were divided into seven categories according to maternal serum TBA levels. Interestingly, birth sizes were reduced, whereas the rate of SGA infants was increased across increasing categories of serum TBA. Compared to category 1, adjusted ORs (95%CI) for SGA infants were 0.99 (0.82-1.21) in category 2, 1.22 (0.97-1.53) in category 3, 1.99 (1.53-2.58) in category 4, 2.91 (2.16-3.93) in category 5, 4.29 (3.33-5.54) in category 6, and 9.01 (5.99-13.53) in category 7, respectively. Furthermore, adjusted ORs (95%CI) for SGA infants for each 1-SD increase in serum TBA levels were 1.36 (1.29-1.43) among all subjects, 2.40 (1.82-3.45) among subjects without cholestasis, and 1.13 (1.06-1.22) among subjects with cholestasis, respectively. These results suggest that gestational cholestasis increases the risk of SGA infants. Additionally, our results indicate strong, continuous associations of serum TBA levels below those diagnostic of cholestasis with a decreased birth sizes and an increased risk of SGA infants.

Foetal oestrogens and autism

Elevated latent prenatal steroidogenic activity has been found in the amniotic fluid of autistic boys, based on measuring prenatal androgens and other steroid hormones. To date, it is unclear if other prenatal steroids also contribute to autism likelihood. Prenatal oestrogens need to be investigated, as they play a key role in synaptogenesis and corticogenesis during prenatal development, in both males and females. Here we test whether levels of prenatal oestriol, oestradiol, oestrone and oestrone sulphate in amniotic fluid are associated with autism, in the same Danish Historic Birth Cohort, in which prenatal androgens were measured, using univariate logistic regression (n = 98 cases, n = 177 controls). We also make a like-to-like comparison between the prenatal oestrogens and androgens. Oestradiol, oestrone, oestriol and progesterone each related to autism in univariate analyses after correction with false discovery rate. A comparison of standardised odds ratios showed that oestradiol, oestrone and progesterone had the largest effects on autism likelihood. These results for the first time show that prenatal oestrogens contribute to autism likelihood, extending the finding of elevated prenatal steroidogenic activity in autism. This likely affects sexual differentiation, brain development and function.

Pre-pregnancy underweight and obesity are positively associated with small-for-gestational-age infants in a Chinese population

The association between suboptimal pre-pregnancy body mass index (BMI) and small-for-gestational-age (SGA) infants is not well defined. We investigated the association between pre-pregnancy BMI and the risk of SGA infants in a Chinese population. We performed a cohort study among 12029 mothers with a pregnancy. This cohort consisted of pregnant women that were: normal-weight (62.02%), underweight (17.09%), overweight (17.77%) and obese (3.12%). Birth sizes were reduced in the underweight and obese groups compared with the normal-weight group. Linear regression analysis indicated that birth size was positively associated with BMI in both the underweight and normal-weight groups. Further analysis showed that 12.74% of neonates were SGA infants in the underweight group, higher than 7.43% of neonates reported in the normal-weight group (adjusted RR = 1.92; 95% CI: 1.61, 2.30). Unexpectedly, 17.60% of neonates were SGA infants in the obese group, much higher than the normal-weight group (adjusted RR = 2.17; 95% CI: 1.57, 3.00). Additionally, 18.40% of neonates were large-for-gestational-age (LGA) infants in the obese group, higher than 7.26% of neonates reported in the normal-weight group (adjusted RR = 3.00; 95% CI: 2.21, 4.06). These results suggest that pre-pregnancy underweight increases the risk of SGA infants, whereas obesity increases the risks of not only LGA infants, but also SGA infants.

Diagnosis and Prediction of Large-For-Gestational-Age Fetus Using the Stacked GeneralizationMethod

An accurate and efficient Large-for-Gestational-Age (LGA) classification system isdeveloped to classify a fetus as LGA or non-LGA, which has the potential to assist paediatricians andexperts in establishing a state-of-the-art LGA prognosis process. The performance of the proposedscheme is validated by using LGA dataset collected from the National Pre-Pregnancy and ExaminationProgram of China (2010–2013). A master feature vector is created to establish primarily datapre-processing, which includes a features’ discretization process and the entertainment of missingvalues and data imbalance issues. A principal feature vector is formed using GridSearch-basedRecursive Feature Elimination with Cross-Validation (RFECV) + Information Gain (IG) featureselection scheme followed by stacking to select, rank, and extract significant features from the LGAdataset. Based on the proposed scheme, different features subset are identified and provided tofour different machine learning (ML) classifiers. The proposed GridSearch-based RFECV+IG featureselection scheme with stacking using SVM (linear kernel) best suits the said classification processfollowed by SVM (RBF kernel) and LR classifiers. The Decision Tree (DT) classifier is not suggestedbecause of its low performance. The highest prediction precision, recall, accuracy, Area Underthe Curve (AUC), specificity, and F1 scores of 0.92, 0.87, 0.92, 0.95, 0.95, and 0.89 are achievedwith SVM (linear kernel) classifier using top ten principal features subset, which is, in fact higherthan the baselines methods. Moreover, almost every classification scheme best performed with tenprincipal feature subsets. Therefore, the proposed scheme has the potential to establish an efficientLGA prognosis process using gestational parameters, which can assist paediatricians and experts toimprove the health of a newborn using computer aided-diagnostic system.

AUTISM SPECTRUM DISORDER AND POSTNATAL FACTORS: A CASE-CONTROL STUDY IN BRAZIL

Objective:

To estimate the magnitude of the association between Autism Spectrum Disorder (ASD) and postnatal factors in a Brazilian population.

Methods:

A case-control study was performed with 253 individuals diagnosed with ASD and 886 individuals without signs of the disorder. A semi-structured questionnaire and the multiple logistic regression model were adopted in the data analysis. To estimate the magnitude of associations, the crude and adjusted Odds Ratio (OR) was used.

Results:

An association with the following factors was found: having been born with congenital malformation (OR 4.24; confidence interval of 95% - 95%CI 1.92-9.34), neonatal jaundice (OR 1.43; 95%CI 1.01-2.02), absence of crying at birth and seizure episode in childhood (OR 5.75; 95%CI 3.37-9.81). The magnitude of the association was higher in the children/adolescents who had two or more postnatal complications (OR 6.39; 95%CI 4.10-10.00).

Conclusions:

The findings of the present study suggest that malformation, neonatal jaundice, absence of crying at birth and seizure episodes in childhood are important factors to be considered when studying the etiology of ASD.

Association of Autism with Maternal Infections, Perinatal and Other Risk Factors: A Case-Control Study

This case-control study explores the association between pregnancy/birth complications and other factors with Autism Spectrum Disorder (ASD) in Lebanese subjects aged 2-18 years. Researchers interviewed 136 ASD cases from the American University of Beirut Medical Center Special Kids Clinic, and 178 controls selected by systematic digit dialing in the Greater-Beirut area. Male gender (Adjusted Odds Ratio [95% CI]: 3.9 [2.2-7.0]); postpartum feeding difficulties (2.5 [1.2-5.4]); maternal infections/complications during pregnancy (2.9 [1.5-5.5], 2.1 [1.1-3.9]); consanguinity (2.5 [1.0-6.0]); family history of psychiatric disorders (2.2 [1.1-4.4]) were risk factors for ASD. Being born first/second (0.52 [0.28-0.95]) and maternal psychological support during pregnancy (0.49 [0.27-0.89]) were negatively associated with ASD. Identifying ASD correlates is crucial for instigating timely screening and subsequent early intervention.

Association of Prenatal Exposure to Air Pollution With Autism Spectrum Disorder

IMPORTANCE

The etiology of autism spectrum disorder (ASD) is poorly understood, but prior studies suggest associations with airborne pollutants.

OBJECTIVE

To evaluate the association between prenatal exposures to airborne pollutants and ASD in a large population-based cohort.

DESIGN, SETTING, AND PARTICIPANTS

This population-based cohort encompassed nearly all births in Metro Vancouver, British Columbia, Canada, from 2004 through 2009, with follow-up through 2014. Children were diagnosed with ASD using a standardized assessment with the Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule. Monthly mean exposures to particulate matter with a diameter less than 2.5 µm (PM2.5), nitric oxide (NO), and nitrogen dioxide (NO2) at the maternal residence during pregnancy were estimated with temporally adjusted, high-resolution land use regression models. The association between prenatal air pollution exposures and the odds of developing ASD was evaluated using logistic regression adjusted for child sex, birth month, birth year, maternal age, maternal birthplace, and neighborhood-level urbanicity and income band. Data analysis occurred from June 2016 to May 2018.

EXPOSURES

Mean monthly concentrations of ambient PM2.5, NO, and NO2 at the maternal residence during pregnancy, calculated retrospectively using temporally adjusted, high-resolution land use regression models.

MAIN OUTCOMES AND MEASURES

Autism spectrum disorder diagnoses based on standardized assessment of the Autism Diagnostic Interview-Revised and Autism Diagnostic Observation Schedule. The hypothesis being tested was formulated during data collection.

RESULTS

In a cohort of 132 256 births, 1307 children (1.0%) were diagnosed with ASD by the age of 5 years. The final sample size for the PM2.5-adjusted model was 129 439 children, and for NO and NO2, it was 129 436 children; of these, 1276 (1.0%) were diagnosed with ASD. Adjusted odds ratios for ASD per interquartile range (IQR) were not significant for exposure to PM2.5 during pregnancy (1.04 [95% CI, 0.98-1.10] per 1.5 μg/m3 increase [IQR] in PM2.5) or NO2 (1.06 [95% CI, 0.99-1.12] per 4.8 ppb [IQR] increase in NO2) but the odds ratio was significant for NO (1.07 [95% CI, 1.01-1.13] per 10.7 ppb [IQR] increase in NO). Odds ratios for male children were 1.04 (95% CI, 0.98-1.10) for PM2.5; 1.09 (95% CI, 1.02-1.15) for NO; and 1.07 (95% CI, 1.00-1.13) for NO2. For female children, they were for 1.03 (95% CI, 0.90-1.18) for PM2.5; 0.98 (95% CI, 0.83-1.13) for NO; and 1.00 (95% CI, 0.86-1.16) for NO2.

CONCLUSIONS AND RELEVANCE

In a population-based birth cohort, we detected an association between exposure to NO and ASD but no significant association with PM2.5 and NO2.

The association between preeclampsia and autism spectrum disorders among children: a meta-analysis

Purpose

In this meta-analysis, relevant case-control and cohort studies were pooled to evaluate the association between preeclampsia and the risk of autism spectrum disorders (ASDs) in children.

Methods

A search for relevant studies in major databases, including Web of Science, PubMed, and Scopus, was performed up to May 2018. The odds ratios (ORs) or rate ratios (RRs) with 95% confidence intervals (CIs) were extracted from eligible studies to determine the association among studies.

Results

The pooled estimates of ORs and RRs indicated a significant association between preeclampsia and ASD [(OR, 1.36; 95% CI, 1.12–1.60) and (RR, 1.30; 95% CI, 1.20–1.41)].

Conclusions

Despite existing controversy, our findings indicated that preeclampsia was associated with an increased risk of ASD among children.

Prenatal metformin exposure or organic cation transporter 3 knock-out curbs social interaction preference in male mice

Poorly managed gestational diabetes can lead to severe complications for mother and child including fetal overgrowth, neonatal hypoglycemia and increased autism risk. Use of metformin to control it is relatively new and promising. Yet safety concerns regarding gestational metformin use remain, as its long-term effects in offspring are unclear. In light of beneficial findings with metformin for adult mouse social behavior, we hypothesized gestational metformin treatment might also promote offspring sociability. To test this, metformin was administered to non-diabetic, lean C57BL/6 J female mice at mating, with treatment discontinued at birth or wean. Male offspring exposed to metformin through birth lost social interaction preference relative to controls by time in chambers, but not by sniffing measures. Further, prenatal metformin exposure appeared to enhance social novelty preference only in females. However due to unbalanced litters and lack of statistical power, firm establishment of any sex-dependency of metformin's effects on sociability was not possible. Since organic cation transporter 3 (OCT3) transports metformin and is dense in placenta, social preferences of OCT3 knock-out males were measured. Relative to wild-type, OCT3 knock-outs had reduced interaction preference. Our data indicate gestational metformin exposure under non-diabetic conditions, or lack of OCT3, can impair social behavior in male C57BL6/J mice. Since OCT3 transports serotonin and tryptophan, impaired placental OCT3 function is one common mechanism that could persistently impact central serotonin systems and social behavior. Yet no gross alterations in serotonergic function were evident by measure of serotonin transporter density in OCT3, or serotonin turnover in metformin-exposed offspring brains. Mechanisms underlying the behavioral outcomes, and if with gestational diabetes the same would occur, remain unclear. Metformin's impacts on placental transporters and serotonin metabolism or AMPK activity in fetal brain need further investigation to clarify benefits and risks to offspring sociability from use of metformin to treat gestational diabetes.

Maternal SSRIs experience and risk of ASD in offspring: a review

Antidepressants are extensively used during pregnancy and associated with severe outcomes, including innate malformations, prematurity, and low birth weight, etc. A recent study suggested that prenatal exposure to antidepressants may impair child neurodevelopment process. Thus, the aim of this review is to investigate the potential association between prenatal use of selective 5-HT reuptake inhibitors (SSRIs) and the risk of autism spectrum disorders (ASDs). Twelve studies related to the linkage between SSRI exposure during pregnancy and ASD in children were explored and compiled. However, there is a knowledge gap concerning the potential link between gestational exposure to antidepressants and the risk of ASDs. Despite such limitations, the available data show that some signal exists and signifies that antenatal exposure to SSRIs may increase the risk of ASDs. Thus, there is a vital need for further, large and well-designed research to definitively evaluate the existence and the magnitude of this severe risk.

Fetal and Infancy Growth Pattern, Cord and Early Childhood Plasma Leptin, and Development of Autism Spectrum Disorder in the Boston Birth Cohort

Leptin is a proinflammatory cytokine that plays an important role in energy homeostasis. Emerging evidence suggests that leptin levels are altered in children with autism spectrum disorder (ASD); however, this has not been studied prospectively. Rapid growth during infancy and early childhood has been implicated in ASD, but the evidence is inconsistent. As leptin is involved in growth and is a potential risk factor for ASD, we explored the associations between (a) cord, early childhood leptin and ASD; and (b) birth weight for gestational age, early childhood weight gain, and ASD. We also assessed the mediating role of leptin in the relationship between weight gain during infancy and ASD. This study was conducted in a sample of 822 subjects from the Boston Birth Cohort. ASD was defined from diagnostic codes in electronic medical records. Extremely rapid weight gain during infancy was associated with a greater ASD risk and this persisted after adjusting for potential confounders (aOR: 3.11; 95% CI: 1.37, 7.07). Similarly, children that had higher plasma leptin levels, prior to ASD diagnosis, had an increased ASD risk in both unadjusted and adjusted models (aOR: 7.87; 95% CI: 2.06, 30.04). Further, early childhood leptin indirectly mediated the relationship between rapid weight gain and ASD. No associations were found between birth weight for gestational age, cord leptin and risk of ASD. Our findings provide a basis to further explore whether the combination of early life growth pattern and a biomarker such as leptin can predict ASD earlier. Autism Res 2018, 11: 1416-1431. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Is early life growth and a biomarker leptin related to ASD risk? To answer this question, we followed 822 children from birth and found that those who gained weight very quickly in infancy, had higher leptin levels in early childhood, had a greater chance of later ASD diagnosis. More research is needed to see if infant's weight gain pattern along with a biomarker (such as leptin) can be used to identify children with ASD sooner.

Prospective Analysis of the Effects of Maternal Immune Activation on Rat Cytokines during Pregnancy and Behavior of the Male Offspring Relevant to Schizophrenia

Influenza during pregnancy is associated with the development of psychopathology in the offspring. We sought to determine whether maternal cytokines produced following administration of viral mimetic polyinosinic-polycytidylic acid (polyI:C) to pregnant rats were predictive of behavioral abnormalities in the adult offspring. Timed-pregnant Sprague Dawley rats received a single intravenous injection of 4-mg/kg polyI:C or saline on gestational day (GD)15. Blood was collected 3 h later for serum analysis of cytokine levels with ELISA. Male offspring were tested in a battery of behavioral tests during adulthood and behavior was correlated with maternal cytokine levels. Maternal serum levels of CXCL1 and interleukin (IL)-6, but not tumor necrosis factor (TNF)-α or CXCL2, were elevated in polyI:C-treated dams. PolyI:C-treated dams experienced post-treatment weight loss and polyI:C pups were smaller than controls at postnatal day (PND)1. Various behavior alterations were seen in the polyI:C-treated offspring. Male polyI:C offspring had enhanced MK-801-induced locomotion, and reduced sociability. PolyI:C offspring failed to display crossmodal and visual memory, and oddity preference was also impaired. Set-shifting, assessed with a lever-based operant conditioning task, was facilitated while touchscreen-based reversal learning was impaired. Correlations were found between maternal serum concentrations of CXCL1, acute maternal temperature and body weight changes, neonatal pup mass, and odd object discrimination and social behavior. Overall, while the offspring of polyI:C-treated rats displayed behavior abnormalities, maternal serum cytokines were not related to the long-term behavior changes in the offspring. Maternal sickness effects and neonatal pup size may be better indicators of later effects of maternal inflammation in the offspring.

Autism spectrum disorder

Autism spectrum disorder is a term used to describe a constellation of early-appearing social communication deficits and repetitive sensory-motor behaviours associated with a strong genetic component as well as other causes. The outlook for many individuals with autism spectrum disorder today is brighter than it was 50 years ago; more people with the condition are able to speak, read, and live in the community rather than in institutions, and some will be largely free from symptoms of the disorder by adulthood. Nevertheless, most individuals will not work full-time or live independently. Genetics and neuroscience have identified intriguing patterns of risk, but without much practical benefit yet. Considerable work is still needed to understand how and when behavioural and medical treatments can be effective, and for which children, including those with substantial comorbidities. It is also important to implement what we already know and develop services for adults with autism spectrum disorder. Clinicians can make a difference by providing timely and individualised help to families navigating referrals and access to community support systems, by providing accurate information despite often unfiltered media input, and by anticipating transitions such as family changes and school entry and leaving.

Different patterns of cortical maturation before and after 38 weeks gestational age demonstrated by diffusion MRI in vivo

Human cortical development during the third trimester is characterised by macro- and microstructural changes which are reflected in alterations in diffusion MRI (dMRI) measures, with significant decreases in cortical mean diffusivity (MD) and fractional anisotropy (FA). This has been interpreted as reflecting increased cellular density and dendritic arborisation. However, the fall in FA stops abruptly at 38 weeks post-menstrual age (PMA), and then tends to plateau, while MD continues to fall, suggesting a more complex picture and raising the hypothesis that after this age development is dominated by continuing increase in neural and organelle density rather than alterations in the geometry of dendritic trees. To test this, we used neurite orientation dispersion and density imaging (NODDI), acquiring multi-shell, high angular resolution dMRI and measures of cortical volume and mean curvature in 99 preterm infants scanned between 25 and 47 weeks PMA. We predicted that increased neurite and organelle density would be reflected in increases in neurite density index (NDI), while a relatively unchanging geometrical structure would be associated with constant orientation dispersion index (ODI). As dendritic arborisation is likely to be one of the drivers of gyrification, we also predicted that measures of cortical volume and curvature would correlate with ODI and show slower growth after 38 weeks.

We observed a decrease of MD throughout the period, while cortical FA decreased from 25 to 38 weeks PMA and then increased. ODI increased up to 38 weeks and then plateaued, while NDI rose after 38 weeks. The evolution of ODI correlated with cortical volume and curvature. Regional analysis of cortical microstructure revealed a heterogenous pattern with increases in FA and NDI after 38 weeks confined to primary motor and sensory regions. These results support the interpretation that cortical development between 25 and 38 weeks PMA shows a predominant increase in dendritic arborisation and neurite growth, while between 38 and 47 weeks PMA it is dominated by increasing cellular and organelle density.

•

DTI and NODDI cortical measures between 25 and 47 weeks GA

•

Early cortical changes consistent with dendritic arborisation and neurite growth

•

After 38 weeks cortical changes consistent with increasing cellular density

•

Cortical curvature evolves in parallel with dendritic arborisation

Infants Born Large for Gestational Age and Developmental Attainment in Early Childhood

Objectives

To investigate if an association exists between being born large for gestational age (LGA) and verbal ability or externalizing behaviour problems at ages 4-5 years.

Method

A secondary analysis was conducted using the National Longitudinal Survey of Children and Youth, including singleton births in 2004-2005 followed till 4-5 years (n = 1685). LGA was defined as a birth weight > 90th percentile. Outcomes included poor verbal ability (scoring < 15th percentile on the Revised Peabody Picture Vocabulary Test) and externalizing behaviour problems (scoring > 90th percentile on externalizing behaviour scales). Multivariable logistic regression with longitudinal standardized funnel weights and bootstrapping estimation were used.

Results

Infants born LGA were not found to be at increased risk for poor verbal ability (aOR: 1.16 [0.49,2.72] and aOR: 0.83 [0.37,1.87] for girls and boys, resp.) or externalizing behaviour problems (aOR: 1.24 [0.52,2.93] and aOR: 1.24 [0.66,2.36] for girls and boys, resp.). Social factors were found to impact developmental attainment. Maternal smoking led to an increased risk for externalizing behaviour problems (aOR: 3.33 [1.60,6.94] and aOR: 2.12 [1.09,4.13] for girls and boys, resp.).

Conclusion

There is no evidence to suggest that infants born LGA are at increased risk for poor verbal ability or externalizing behaviour problems.

Association between hypertensive disorders of pregnancy and risk of autism in offspring: a systematic review and meta-analysis of observational studies

Background

Autism spectrum disorder (ASD) is a common severe pervasive neurodevelopmental disorder of undetermined etiology. Environmental exposures, especially pregnancy complications, have been increasingly recognized as a potential risk factor for ASD. Our aim was to (1) systematically evaluate the association between hypertensive disorders of pregnancy (HDP) and the risk of ASD in offspring, (2) specifically draw a subgroup analysis of disease severity in patients with HDP to achieve more sufficient evidence on this issue.

Results

A total of 21 studies were identified with more than 6.5 million participants, including 31,027 ASD probands. A comparative meta-analysis established that offspring born premature to HDP were significantly associated with ASD than matched controls (OR = 1.42, 95% CI: 1.34–1.50). Subgroup analysis of clinical classification include: (1) gestational hypertension, (2) pre-eclampsia, (3) chronic hypertension complicating pregnancy (CHP). The offspring of mothers with pre-eclampsia and CHP have slightly higher risk (OR = 1.43; OR = 1.48, respectively) of ASD than those of mothers with gestational hypertension (OR = 1.37). In consistence with most previous researches, higher ASD prevalence was observed in male than female (OR = 1.38), indicating a potential role for gender in the pathophysiology of ASD.

Materials and Methods

We conducted a systematic literature search on PubMed, EMBASE, Web of Science, PsycINFO database and China National Knowledge Infrastructure up to Jun. 2017. Statistical analysis was performed using Stata 10.0.

Conclusions

This meta-analysis implies a possible link between HDP and the risk of ASD in offspring. However, further investigation should be conducted to confirm this conclusion, and intensive prenatal surveillance and early prediction for ASD is needed.

Expression of placental regulatory genes is associated with fetal growth

The placenta is the principal organ regulating respiratory, nutritional, endocrine and metabolic functions on behalf of the developing fetus. Changes in gene expression patterns of placenta-specific genes may influence fetal growth. We profiled the expression of 17 genes related to placenta functioning in term placentas (n=677) to identify genes differentially expressed across birth weight categories [small (SGA), appropriate (AGA) and large (LGA) for gestational age]. ABCG2, CEBPB, CRH, GCM1, GPC3, INSL4, PGF and PLAC1 were inversely associated with LGA status, with odds ratios (ORs) and 95% confidence intervals (CI) ranging from GCM1 (OR=0.44, 95% CI: 0.29, 0.70) to CRH (OR=0.73, 95% CI: 0.61, 0.88). NR3C1 was positively associated with LGA status (OR=2.33, 95% CI: 1.43, 3.78). PLAC1 (OR=0.66, 95% CI: 0.47, 0.92) and ABCG2 (OR=0.63, 95% CI: 0.44, 0.91) were additionally inversely associated with SGA status, and PGF was positively associated with SGA status (OR=1.59, 95% CI=1.08, 2.35). General trends were confirmed in an independent cohort (n=306). Given that aberrant fetal growth may have long-lasting effects, our results suggest the potential utility of placental gene expression profiles as potential early markers of disease onset later in life.

The clinical significance of an estimated fetal weight below the 10th percentile: a comparison of outcomes of <5th vs 5th-9th percentile

BACKGROUND

The association between small-for-gestational-age (birthweight <10th percentile for gestational age) and neonatal morbidity is well established. Yet, there is a paucity of data on the relationship between suspected small for gestational age (sonographic-estimated fetal weight <10th percentile) at 2 thresholds and subsequent neonatal morbidity.

OBJECTIVE

The objective of this study was to determine the relationship between sonographic-estimated fetal weight <5th percentile vs 5-9th percentile and neonatal morbidity.

STUDY DESIGN

This retrospective study involved 5 centers and included nonanomalous, singletons with sonographic-estimated fetal weight <10th percentile for gestational age who delivered from 2009-2012. Composite neonatal morbidity included respiratory distress syndrome, proven sepsis, intraventricular hemorrhage grade III or IV, necrotizing enterocolitis, thrombocytopenia, seizures, or death. Odd ratios were adjusted for center, maternal age, race, body mass index at first visit, smoking status, use of alcohol, use of drugs, and neonatal gender.

RESULTS

Of 834 women with suspected small-for-gestational-age fetuses, 513 (62%) had sonographic-estimated fetal weight <5th percentile, and 321 (38%) had sonographic-estimated fetal weight of 5-9th percentile for gestational age. At delivery, 81% of women with a suspected small-for-gestational-age fetus had a confirmed small-for-gestational-age fetus. In the group with a sonographic-estimated fetal weight <5th percentile, 59% of neonates had birthweight <5th percentile; in the group with a sonographic-estimated fetal weight 5-9th percentile, 41% had birthweight <5th percentile, and 36% had birthweight at 5-9th percentile. Neonatal intensive care unit admission differed significantly for those fetuses at <5th percentile (29%) compared with those fetuses at 5-9th percentile (15%; P<.001). The composite neonatal morbidity among the sonographic-estimated fetal weight <5th percentile group was higher than the sonographic-estimated fetal weight of 5-9th percentile group (31% vs 13%; adjusted odds ratio, 2.41; 95% confidence interval, 1.53-3.80). Similar findings were noted when the analysis was limited to sonographic-estimated fetal weight within 28 days of delivery (adjusted odds ratio, 2.22; 95% confidence interval, 1.34-3.67).

CONCLUSION

Eight of 10 suspected small-for-gestational-age fetuses had birthweight <10th percentile for gestational age; the prediction of actual birthweight was more accurate in the <5th percentile group. Neonates with sonographic-estimated fetal weight of <5th percentile were more likely to be admitted to the neonatal intensive care unit and have complications than were those neonates with sonographic-estimated fetal weight of 5-9th percentile.

Whole-transcriptome analysis delineates the human placenta gene network and its associations with fetal growth

BACKGROUND

The placenta is the principal organ regulating intrauterine growth and development, performing critical functions on behalf of the developing fetus. The delineation of functional networks and pathways driving placental processes has the potential to provide key insight into intrauterine perturbations that result in adverse birth as well as later life health outcomes.

RESULTS

We generated the transcriptome-wide profile of 200 term human placenta using the Illumina HiSeq 2500 platform and characterized the functional placental gene network using weighted gene coexpression network analysis (WGCNA). We identified 17 placental coexpression network modules that were dominated by functional processes including growth, organ development, gas exchange and immune response. Five network modules, enriched for processes including cellular respiration, amino acid transport, hormone signaling, histone modifications and gene expression, were associated with birth weight; hub genes of all five modules (CREB3, DDX3X, DNAJC14, GRHL1 and C21orf91) were significantly associated with fetal growth restriction, and one hub gene (CREB3) was additionally associated with fetal overgrowth.

CONCLUSIONS

In this largest RNA-Seq based transcriptome-wide profiling study of human term placenta conducted to date, we delineated a placental gene network with functional relevance to fetal growth using a network-based approach with superior scale reduction capacity. Our study findings not only implicate potential molecular mechanisms underlying fetal growth but also provide a reference placenta gene network to inform future studies investigating placental dysfunction as a route to future disease endpoints.

Dynamic interaction between fetal adversity and a genetic score reflecting dopamine function on developmental outcomes at 36 months

Background

Fetal adversity, evidenced by poor fetal growth for instance, is associated with increased risk for several diseases later in life. Classical cut-offs to characterize small (SGA) and large for gestational age (LGA) newborns are used to define long term vulnerability. We aimed at exploring the possible dynamism of different birth weight cut-offs in defining vulnerability in developmental outcomes (through the Bayley Scales of Infant and Toddler Development), using the example of a gene vs. fetal adversity interaction considering gene choices based on functional relevance to the studied outcome.

Methods

36-month-old children from an established prospective birth cohort (Maternal Adversity, Vulnerability, and Neurodevelopment) were classified according to birth weight ratio (BWR) (SGA ≤0.85, LGA >1.15, exploring a wide range of other cut-offs) and genotyped for polymorphisms associated with dopamine signaling (TaqIA-A1 allele, DRD2-141C Ins/Ins, DRD4 7-repeat, DAT1-10- repeat, Met/Met-COMT), composing a score based on the described function, in which hypofunctional variants received lower scores.

Results

There were 251 children (123 girls and 128 boys). Using the classic cut-offs (0.85 and 1.15), there were no statistically significant interactions between the neonatal groups and the dopamine genetic score. However, when changing the cut-offs, it is possible to see ranges of BWR that could be associated with vulnerability to poorer development according to the variation in the dopamine function.

Conclusion

The classic birth weight cut-offs to define SGA and LGA newborns should be seen with caution, as depending on the outcome in question, the protocols for long-term follow up could be either too inclusive—therefore most costly, or unable to screen true vulnerabilities—and therefore ineffective to establish early interventions and primary prevention.

The Changing Epidemiology of Autism Spectrum Disorders

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition with lifelong impacts. Genetic and environmental factors contribute to ASD etiology, which remains incompletely understood. Research on ASD epidemiology has made significant advances in the past decade. Current prevalence is estimated to be at least 1.5% in developed countries, with recent increases primarily among those without comorbid intellectual disability. Genetic studies have identified a number of rare de novo mutations and gained footing in the areas of polygenic risk, epigenetics, and gene-by-environment interaction. Epidemiologic investigations focused on nongenetic factors have established advanced parental age and preterm birth as ASD risk factors, indicated that prenatal exposure to air pollution and short interpregnancy interval are potential risk factors, and suggested the need for further exploration of certain prenatal nutrients, metabolic conditions, and exposure to endocrine-disrupting chemicals. We discuss future challenges and goals for ASD epidemiology as well as public health implications.