Maternal Body Mass Index and Risk of Autism Spectrum Disorders in Offspring: A Meta-analysis

Maternal polycystic ovarian syndrome and offspring psychopathology and neurodevelopment

Polycystic ovarian syndrome (PCOS) is a common female endocrinologic condition that affects both the metabolic and reproductive systems and is the most frequent cause of anovulatory infertility. It is also associated with a range of psychiatric outcomes in individuals, including bulimia nervosa, schizophrenia, bipolar disorder, depression, anxiety, and personality disorders. At the same time, evidence suggests that hyperandrogenism, the characteristic trait of PCOS, may impair fetal neurodevelopment. Epidemiological studies have linked maternal PCOS with a variety of behavioral and psychiatric conditions in offspring including autism spectrum disorder and attention deficit hyperactivity disorder. In this review, we explore evidence for potential underlying biological mechanisms that might explain these observed associations, discuss the complex interplay between genetics and various environmental factors across generations, and highlight avenues for future research.

Maternal high fat and high sugar diet impacts on key DNA methylation enzymes in offspring brain in a sex-specific manner

Maternal obesity associates with an increased risk of offspring neurodevelopmental disorders. Although the underlying mechanism(s) remain unclear, evidence suggests a role for altered DNA methylation. We utilized a murine model of diet-induced obesity to investigate the impact of maternal obesity on the offspring brain transcriptome and DNA methylation. C57Bl/6 dams were fed high-fat high-sugar (HFD, n = 7) or control (CON, n = 7) diets. Maternal obesity/hyperglycemia associated with offspring growth restriction, with brain-sparing specifically in females. Postnatal hypoglycemia was seen in HFD males, but not females. The 3' RNA-sequencing revealed perturbations in metabolic and cell differentiation pathways in neonatal male and female offspring frontal cortex and cerebellum. Compared with controls, HFD males, but not females, had lower cortical and cerebellar DNMT gene and protein expression, and reduced cerebellar TET enzyme mRNA. Whilst female offspring had lower cerebellar 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) than males, there were no effects of HFD on 5mC/5hmC in cortex or cerebellum in either sex. Our data suggest that maternal obesity has sex-specific effects on fetal neurodevelopment, including enzymes involved in DNA methylation/demethylation. These mechanisms may play a role in the increased risk of neurodevelopmental disorders following obese/diabetic pregnancies, including increased male susceptibility to these disorders.

The Possible Role of Postnatal Biphasic Dysregulation of IGF-1 Tone in the Etiology of Idiopathic Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a pervasive condition of neurodevelopmental origin with an increasing burden on society. Idiopathic ASD is notorious for its heterogeneous behavioral manifestations, and despite substantial efforts, its etiopathology is still unclear. An increasing amount of data points to the causative role of critical developmental alterations in the first year of life, although the contribution of fetal, environmental, and genetic factors cannot be clearly distinguished. This review attempts to propose a narrative starting from neuropathological findings in ASD, involving insulin-like growth factor 1 (IGF-1) as a key modulator and demonstrates how the most consistent gestational risk factors of ASD-maternal insulin resistance and fetal growth insufficiency-converge at the perinatal dysregulation of offspring anabolism in the critical period of early development. A unifying hypothesis is derived, stating that the co-occurrence of these gestational conditions leads to postnatal biphasic dysregulation of IGF-1 tone in the offspring, leading first to insulin-dependent accelerated development, then to subsequent arrest of growth and brain maturation in ASD as an etiologic process. This hypothesis is tested for its explanation of various widely reported risk factors and observations of idiopathic ASD, including early postnatal growth abnormalities, the pervasive spectrum of symptoms, familial predisposition, and male susceptibility. Finally, further directions of research are outlined.

Metabolomic and transcriptomic remodeling of bone marrow myeloid cells in response to maternal obesity

Maternal obesity puts the offspring at high risk of developing obesity and cardiometabolic diseases in adulthood. Here, we utilized a mouse model of maternal high-fat diet (HFD)-induced obesity that recapitulates metabolic perturbations seen in humans. We show increased adiposity in the offspring of HFD-fed mothers (Off-HFD) when compared with the offspring of regular diet-fed mothers (Off-RD). We have previously reported significant immune perturbations in the bone marrow of newly weaned Off-HFD. Here, we hypothesized that lipid metabolism is altered in the bone marrow of Off-HFD versus Off-RD. To test this hypothesis, we investigated the lipidomic profile of bone marrow cells collected from 3-week-old Off-RD and Off-HFD. Diacylglycerols (DAGs), triacylglycerols (TAGs), sphingolipids, and phospholipids were remarkably different between the groups, independent of fetal sex. Levels of cholesteryl esters were significantly decreased in Off-HFD, suggesting reduced delivery of cholesterol. These were accompanied by age-dependent progression of mitochondrial dysfunction in bone marrow cells. We subsequently isolated CD11b+ myeloid cells from 3-wk-old mice and conducted metabolomic, lipidomic, and transcriptomic analyses. The lipidomic profiles of myeloid cells were similar to those of bone marrow cells and included increases in DAGs and decreased TAGs. Transcriptomics revealed altered expression of genes related to immune pathways, including macrophage alternative activation, B-cell receptors, and transforming growth factor-β signaling. All told, this study revealed lipidomic, metabolomic, and gene expression abnormalities in bone marrow cells broadly, and in bone marrow myeloid cells particularly, in the newly weaned offspring of mothers with obesity, which might at least partially explain the progression of metabolic and cardiovascular diseases in their adulthood.NEW & NOTEWORTHY Our data revealed significant immunometabolic perturbations in the bone marrow and myeloid cells in the newly weaned offspring born to mothers with obesity. Adaptation to an adverse maternal intrauterine environment affects bone marrow metabolism at a very young age and might affect responses to immune challenges that appear later in life, for example, infections or cancer.

Sex-specific associations between maternal prenatal inflammation and offspring cortical morphology in youth: A harmonised study across four birth cohorts

Maternal immune activation (MIA) during pregnancy is implicated in offspring psychiatric disorders. However, it is unknown to what extent MIA affects neurodevelopment, particularly cerebrocortical anatomy, in the general population, and whether effects differ by sex. The current study used vertex-wise statistics to examine the association between maternal prenatal CRP, an archetypal systemic inflammatory marker, and offspring cortical thickness, surface area, and volume, in 2635 mother-child dyads (5.4-26.5 years) from three population-based cohorts, and one clinical cohort enriched for presence of inflammation markers. Maternal CRP within a normal physiological range (<10 mg/L) exhibited sex-specific quadratic associations with cortical morphological measures in 2 regions in males and 1 region in females at childhood. Elevated (>10 mg/L) CRP was associated with regional cortical morphology in females and in a pooled sample of sexes. Overall, MIA is associated with cortical development in a regional and sex-specific manner in studies spanning childhood to adulthood.

The role of multiple birth and birth complications in the association between assisted reproductive technology conception and autism diagnosis

In recent decades, the use of assisted reproductive technology (ART) has increased rapidly. To assess the relationship between ART and autism diagnosis, we linked California birth records from 2000 through 2016 with contemporaneous records from the National ART Surveillance System (NASS) and autism caseload records from California's Department of Developmental Services from 2000 through November 2019. All 95 149 birth records that were successfully linked to a NASS record, indicating an ART birth, were matched 1:1 using propensity scores to non-ART births. We calculated the hazard risk ratio for autism diagnosis and the proportions of the relationship between ART conception and autism diagnosis mediated by multiple birth pregnancy and related birth complications. The hazard risk ratio for autism diagnosis following ART compared with non-ART conception is 1.26 (95% CI, 1.17-1.35). Multiple birth, preterm birth, and cesarean delivery jointly mediate 77.9% of the relationship between ART conception and autism diagnosis. Thus, increased use of single embryo transfer in the United States to reduce multiple births and related birth complications may be a strategy to address the risk of autism diagnosis among ART-conceived children.

Metabolomic and transcriptomic remodeling of bone marrow myeloid cells in response to maternal obesity

Maternal obesity puts the offspring at high risk of developing obesity and cardio-metabolic diseases in adulthood. Here, using a mouse model of maternal high-fat diet (HFD)-induced obesity, we show that whole body fat content of the offspring of HFD-fed mothers (Off-HFD) increases significantly from very early age when compared to the offspring regular diet-fed mothers (Off-RD). We have previously shown significant metabolic and immune perturbations in the bone marrow of newly-weaned offspring of obese mothers. Therefore, we hypothesized that lipid metabolism is altered in the bone marrow Off-HFD in newly-weaned offspring of obese mothers when compared to the Off-RD. To test this hypothesis, we investigated the lipidomic profile of bone marrow cells collected from three-week-old offspring of regular and high fat diet-fed mothers. Diacylgycerols (DAGs), triacylglycerols (TAGs), sphingolipids and phospholipids, including plasmalogen, and lysophospholipids were remarkably different between the groups, independent of fetal sex. Levels of cholesteryl esters were significantly decreased in offspring of obese mothers, suggesting reduced delivery of cholesterol to bone marrow cells. This was accompanied by age-dependent progression of mitochondrial dysfunction in bone marrow cells. We subsequently isolated CD11b+ myeloid cells from three-week-old mice and conducted metabolomics, lipidomics, and transcriptomics analyses. The lipidomic profiles of these bone marrow myeloid cells were largely similar to that seen in bone marrow cells and included increases in DAGs and phospholipids alongside decreased TAGs, except for long-chain TAGs, which were significantly increased. Our data also revealed significant sex-dependent changes in amino acids and metabolites related to energy metabolism. Transcriptomic analysis revealed altered expression of genes related to major immune pathways including macrophage alternative activation, B-cell receptor signaling, TGFβ signaling, and communication between the innate and adaptive immune systems. All told, this study revealed lipidomic, metabolomic, and gene expression abnormalities in bone marrow cells broadly, and in bone marrow myeloid cells particularly, in the newly-weaned offspring of obese mothers, which might at least partially explain the progression of metabolic and cardiovascular diseases in their adulthood.

Maternal obesity: sex-specific in utero changes in fetal brain autophagy and mTOR

OBJECTIVE

Maternal obesity affects 39.7% of reproductive-age women in the United States. Emerging research has suggested that in utero exposure to maternal obesity is associated with adverse neurodevelopmental outcomes, but knowledge of underlying mechanisms in human samples is lacking.

METHODS

A matched case-control study was performed in women with singleton fetuses who were undergoing elective pregnancy termination at gestational ages 15 to 21 weeks. Maternal adiponectin levels from plasma were measured using ELISA kits. RNA was extracted from fetal brain tissue using RNeasy Mini Kit (QIAGEN). mRNA expression from ADIPOR1, ADIPOR2, MTOR, ATG5, ATG7, BECN1, and MAP1LC3B was quantified through the ΔΔCt method and using GAPDH as a housekeeping gene.

RESULTS

We have identified transcription patterns associated with inhibition of autophagy in male fetal brain tissue exposed to maternal obesity (↑MTOR, ↓ATG5, ↓ATG7, and ↓MAP1LC3B), with female fetuses demonstrating either no change in transcription or nonsignificant changes associated with increased autophagy. There was significant downregulation of the autophagy-associated gene BECN1 in both male and female individuals who were exposed to obesity in utero.

CONCLUSIONS

We present novel evidence suggesting that in utero exposure to maternal obesity in humans may significantly affect neurodevelopment, especially in male fetuses, through alterations in normal autophagy molecular mechanisms and with adiponectin as a potential mediator.

Autism spectrum disorders and the gastrointestinal tract: insights into mechanisms and clinical relevance

Autism spectrum disorders (ASDs) are recognized as central neurodevelopmental disorders diagnosed by impairments in social interactions, communication and repetitive behaviours. The recognition of ASD as a central nervous system (CNS)-mediated neurobehavioural disorder has led most of the research in ASD to be focused on the CNS. However, gastrointestinal function is also likely to be affected owing to the neural mechanistic nature of ASD and the nervous system in the gastrointestinal tract (enteric nervous system). Thus, it is unsurprising that gastrointestinal disorders, particularly constipation, diarrhoea and abdominal pain, are highly comorbid in individuals with ASD. Gastrointestinal problems have also been repeatedly associated with increased severity of the core symptoms diagnostic of ASD and other centrally mediated comorbid conditions, including psychiatric issues, irritability, rigid-compulsive behaviours and aggression. Despite the high prevalence of gastrointestinal dysfunction in ASD and its associated behavioural comorbidities, the specific links between these two conditions have not been clearly delineated, and current data linking ASD to gastrointestinal dysfunction have not been extensively reviewed. This Review outlines the established and emerging clinical and preclinical evidence that emphasizes the gut as a novel mechanistic and potential therapeutic target for individuals with ASD.

Maternal Pregnancy and Pre-Pregnancy Weight and Behavioural Outcomes in Children

Reported associations of pre-pregnancy weight and/or gestational weight gain with offspring behavioural outcomes are inconsistent. Using data from the Avon Longitudinal Study of Parents and Children (ALSPAC), this study aimed to examine these associations at five developmental stages between the ages of 3 and 16. Over 6800 mother-offspring pairs at age 3 and 3925 pairs at age 16 were included. Pre-pregnancy underweight was associated with a 22% increased risk of total behavioural difficulties (OR = 1.22, 95% CI 1.02-1.45). In separate analyses using the SDQ subscales, pre-pregnancy underweight was linked to a 37% (OR = 1.37, 95% CI 1.14-1.65) and 33% (OR = 1.33, 95% CI 1.01-1.76) increased risk of emotional symptoms and prosocial behaviour problems over time, respectively. While pre-pregnancy overweight was associated with an 11% (OR = 1.11, 95% CI 1.03-1.20) and 18% (OR = 1.18, 95% CI 1.03-1.36) increased risk of conduct and peer relationship problems, respectively, pregnancy obesity was associated with a 43% increased risk of emotional problems (OR = 1.43, 95% CI 1.16-1.77). We found no evidence of associations between gestational weight gain and child behaviour except for a reduced risk in prosocial behaviour problems (OR = 0.82, 95% CI 0.70-0.96). Our findings provide insights into the link between preconception BMI and child behaviour, underscoring the necessity for further research to validate these associations and elucidate underlying mechanisms.

The early life exposome and autism risk: a role for the maternal microbiome?

Autism spectrum disorders (ASD) are highly heritable, heterogeneous neurodevelopmental disorders characterized by clinical presentation of atypical social, communicative, and repetitive behaviors. Over the past 25 years, hundreds of ASD risk genes have been identified. Many converge on key molecular pathways, from translational control to those regulating synaptic structure and function. Despite these advances, therapeutic approaches remain elusive. Emerging data unearthing the relationship between genetics, microbes, and immunity in ASD suggest an integrative physiology approach could be paramount to delivering therapeutic breakthroughs. Indeed, the advent of large-scale multi-OMIC data acquisition, analysis, and interpretation is yielding an increasingly mechanistic understanding of ASD and underlying risk factors, revealing how genetic susceptibility interacts with microbial genetics, metabolism, epigenetic (re)programming, and immunity to influence neurodevelopment and behavioral outcomes. It is now possible to foresee exciting advancements in the treatment of some forms of ASD that could markedly improve quality of life and productivity for autistic individuals. Here, we highlight recent work revealing how gene X maternal exposome interactions influence risk for ASD, with emphasis on the intrauterine environment and fetal neurodevelopment, host-microbe interactions, and the evolving therapeutic landscape for ASD.

Pre-autism: What a paediatrician should know about early diagnosis of autism‎

Autism, also known as an autism spectrum disorder, is a complex neurodevelopmental disorder usually diagnosed in the first three years of a child's life. A range of symptoms characterizes it and can be diagnosed at any age, including adolescence and adulthood. However, early diagnosis is crucial for effective management, prognosis, and care. Unfortunately, there are no established fetal, prenatal, or newborn screening programs for autism, making early detection difficult. This review aims to shed light on the early detection of autism prenatally, natally, and early in life, during a stage we call as "pre-autism" when typical symptoms are not yet apparent. Some fetal, neonatal, and infant biomarkers may predict an increased risk of autism in the coming baby. By developing a biomarker array, we can create an objective diagnostic tool to diagnose and rank the severity of autism for each patient. These biomarkers could be genetic, immunological, hormonal, metabolic, amino acids, acute phase reactants, neonatal brainstem function biophysical activity, behavioral profile, body measurements, or radiological markers. However, every biomarker has its accuracy and limitations. Several factors can make early detection of autism a real challenge. To improve early detection, we need to overcome various challenges, such as raising community awareness of early signs of autism, improving access to diagnostic tools, reducing the stigma attached to the diagnosis of autism, and addressing various culturally sensitive concepts related to the disorder.

Is the association between mothers' autistic traits and childhood autistic traits moderated by maternal pre-pregnancy body mass index?

BACKGROUND

Previous studies showed that there is a positive association between mothers' and children's autistic traits. We also tested if this association is more pronounced in mothers with a higher pre-pregnancy body mass index (BMI).

METHOD

The study was embedded in two cohorts with information available for 4,659 participants from the Generation R and for 179 participants from the Cambridge Ultrasound Siblings and Parents Project (CUSP) cohort. In both cohorts, maternal autistic traits were assessed using the short form of the Autism Spectrum Quotient, and information about maternal height and weight before pregnancy was obtained by questionnaire. Child autistic traits were assessed with the short form of Social Responsiveness Scale in Generation R (M = 13.5 years) and with the Quantitative Checklist for Autism in Toddlers (Q-CHAT) in the CUSP cohort (M = 1.6 years).

RESULT

Higher maternal autistic traits were associated with higher autistic traits in toddlerhood (CUSP cohort; βadjusted = 0.20, p < 0.01), in early childhood (Generation R; βadjusted = 0.19, p < 0.01), and in early adolescence (Generation R; βadjusted = 0.16, p < 0.01). Furthermore, a higher maternal pre-pregnancy BMI was associated with higher child autistic traits, but only in Generation R (βadjusted = 0.03, p < 0.01). There was no significant moderating effect of maternal pre-pregnancy BMI on the association between autistic traits of mothers and children, neither in Generation R nor in CUSP. In addition, child autistic traits scores were significantly higher in mothers who were underweight and in mothers who were overweight compared to mothers with a healthy weight.

CONCLUSION

We confirm the association between maternal and child autistic traits in toddlerhood, early childhood, and early adolescence. Potential interacting neurobiological processes remain to be confirmed.

Environmental Influences on Individuals with Autistic Spectrum Disorders with Special Emphasis on Seasonality: An Overview

This paper offers an in-depth exploration of the intricate relationship between environmental factors and autism spectrum disorder (ASD), with a special emphasis on seasonality. It reviews existing research, providing a comprehensive summary of findings and highlighting the multifaceted dimensions of several environmental factors influencing the etiology of ASD. The discussion encompasses various elements, including birth months, maternal health, dietary choices, and vitamin D deficiency, delving into the intricate interplay of seasonality with environmental influences such as viral infections and solar radiation. The present study raises essential questions regarding the timing of environmental influences and the factors contributing to the rising prevalence of ASD. Ultimately, it underscores the need for future epidemiological research to incorporate more extensive investigations of environmental risk factors and employ advanced statistical analyses. This comprehensive overview contributes to a deeper understanding of how environmental factors, particularly seasonality, may be linked to the occurrence of ASD and its increasing prevalence, recognizing the multifaceted and diverse nature of these interactions.

Relationship of Nonsteroidal Anti-Inflammatory Drug Use During Pregnancy with Autism Spectrum Disorder and Intellectual Disability Among Offspring

Objective: This study aimed to examine the association of nonsteroidal anti-inflammatory drug (NSAID) use by pregnant women during pregnancy with autism spectrum disorder (ASD) and intellectual disability (ID) in their children among Medicaid-insured mother-child dyads. Materials and Methods: We conducted a retrospective cohort study linking multiple datasets of South Carolina for the years between 2010 and 2017, in which the main exposure variable was NSAID use during pregnancy and outcome variables were ASD only, ID only, and ASD with ID. We conducted a multinomial logistic regression analysis, controlling for identified risk factors for ASD (mother's age, race, body-mass index, preeclampsia, and gestational diabetes). Results: NSAID use during pregnancy was found to be associated with ID only in both unadjusted and adjusted analyses. Children with mothers who had NSAID prescriptions were 26% more likely to have ID in comparison with children whose mothers did not have NSAID prescriptions (odds ratio: 1.26 [1.10-1.46]). The other risk factors identified for ASD were maternal age, race, preeclampsia, smoking, low birth weight, and obesity. For ID, the risk factors were maternal age, race, smoking, birth weight, overweight, and obesity, all of which were also associated with ASD with ID, except for overweight. Conclusions: NSAID usage during pregnancy was found to be associated with ID only and not with ASD. However, more research is needed to validate the effect of NSAIDs during pregnancy on ASD and ID among children.

Prenatal programing of motivated behaviors: can innate immunity prime behavior?

Prenatal programming during pregnancy sets physiological outcomes in the offspring by integrating external or internal stimuli. Accordingly, pregnancy is an important stage of physiological adaptations to the environment where the fetus becomes exposed and adapted to the maternal milieu. Maternal exposure to high-energy dense diets can affect motivated behavior in the offspring leading to addiction and impaired sociability. A high-energy dense exposure also increases the pro-inflammatory cytokines profile in plasma and brain and favors microglia activation in the offspring. While still under investigation, prenatal exposure to high-energy dense diets promotes structural abnormalities in selective brain regions regulating motivation and social behavior in the offspring. The current review addresses the role of energy-dense foods programming central and peripheral inflammatory profiles during embryonic development and its effect on motivated behavior in the offspring. We provide preclinical and clinical evidence that supports the contribution of prenatal programming in shaping immune profiles that favor structural and brain circuit disruption leading to aberrant motivated behaviors after birth. We hope this minireview encourages future research on novel insights into the mechanisms underlying maternal programming of motivated behavior by central immune networks.

Maternal Exposure to Pesticides and Risk of Autism Spectrum Disorders in Offspring: A Meta-analysis

This meta-analysis was conducted to estimate the overall association between maternal exposure to pesticides and risk of ASD in offspring. PubMed, EMBASE, Web of Science, and the PsycINFO were searched until December 30, 2020 to include eligible studies. Eight studies with 50,426 participants, 5810 of whom had ASD, were involved in the study. Overall, the summary OR (95% confidence interval) of ASDs in offspring for maternal exposure to pesticide estimated by residential proximity measures and self-report was 1.88 (1.10-3.20). However, maternal exposure to pesticide measured by biomarkers was not associated with an increased risk of ASDs (pooled OR 1.13; 95% CI 0.83-1.54). Further well-designed studies are needed to confirm our findings.

Maternal Metabolic State and Fetal Sex and Genotype Modulate Methylation of the Serotonin Receptor Type 2A Gene (HTR2A) in the Human Placenta

The serotonin receptor 2A gene (HTR2A) is a strong candidate for the fetal programming of future behavior and metabolism. Maternal obesity and gestational diabetes mellitus (GDM) have been associated with an increased risk of metabolic and psychological problems in offspring. We tested the hypothesis that maternal metabolic status affects methylation of HTR2A in the placenta. The prospective study included 199 pairs of mothers and healthy full-term newborns. Genomic DNA was extracted from feto-placental samples and analyzed for genotypes of two polymorphisms (rs6311, rs6306) and methylation of four cytosine residues (−1665, −1439, −1421, −1224) in the HTR2A promoter region. Placental HTR2A promoter methylation was higher in male than female placentas and depended on both rs6311 and rs6306 genotypes. A higher maternal pre-gestational body mass index (pBMI) and, to a lesser extent, diagnosis of GDM were associated with reduced HTR2A promoter methylation in female but not male placentas. Higher pBMI was associated with reduced methylation both directly and indirectly through increased GDM incidence. Tobacco use during pregnancy was associated with reduced HTR2A promoter methylation in male but not female placentas. The obtained results suggest that HTR2A is a sexually dimorphic epigenetic target of intrauterine exposures. The findings may contribute to a better understanding of the early developmental origins of neurobehavioral and metabolic disorders associated with altered HTR2A function.

Early life environmental factors associated with autism spectrum disorder symptoms in children at age 2 years: A birth cohort study

LAY ABSTRACT

Mounting evidence indicates the contribution of early life environmental factors in autism spectrum disorder. We aim to report the prospective associations between early life environmental factors and autism spectrum disorder symptoms in children at the age of 2 years in a population-derived birth cohort, the Barwon Infant Study. Autism spectrum disorder symptoms at the age of 2 years strongly predicted autism spectrum disorder diagnosis by the age of 4 years (area under curve = 0.93; 95% CI (0.82, 1.00)). After adjusting for child's sex and age at the time of behavioural assessment, markers of socioeconomic disadvantage, such as lower household income and lone parental status; maternal health factors, including younger maternal age, maternal pre-pregnancy body mass index, higher gestational weight gain and prenatal maternal stress; maternal lifestyle factors, such as prenatal alcohol and environmental air pollutant exposures, including particulate matter < 2.5 μm at birth, child secondhand tobacco smoke at 12 months, dampness/mould and home heating with oil, kerosene or diesel heaters at 2 years postnatal. Lower socioeconomic indexes for area, later birth order, higher maternal prenatal depression and maternal smoking frequency had a dose-response relationship with autism spectrum disorder symptoms. Future studies on environmental factors and autism spectrum disorder should consider the reasons for the socioeconomic disparity and the combined impact of multiple environmental factors through common mechanistic pathways.

Maternal Midpregnancy Leptin and Adiponectin Levels as Predictors of Autism Spectrum Disorders: A Prenatal Cohort Study

CONTEXT

Autism spectrum disorders (ASDs) are a group of conditions characterized by impaired social function and repetitive behaviors. Their etiology is largely unknown.

OBJECTIVE

This work aims to examine the associations of maternal second-trimester and cord blood leptin and adiponectin levels with ASDs in offspring.

METHODS

We used data from 1164 mother-child pairs enrolled in Project Viva, a prospective prebirth cohort. We used logistic regression analysis to examine the associations of leptin and adiponectin levels in maternal second-trimester blood and cord blood obtained at birth with ASDs. Additionally, we examined the association of maternal prepregnancy body mass index (BMI) as an exposure. Main outcome measures included doctor-diagnosed ASDs reported by mothers using questionnaires in midchildhood and early adolescence.

RESULTS

The cumulative incidence of ASDs was 3.4%. Maternal prepregnancy BMI (per 5 points) was positively associated with ASDs in a logistic regression model adjusted for maternal race/ethnicity, education, smoking status and child sex (adjusted odds ratio [OR] 1.38; 95% CI, 1.06-1.79). Higher second-trimester adiponectin was associated with lower odds of ASD in offspring (unadjusted OR 0.49; 95% CI, 0.30-0.78; and OR 0.54; 95% CI, 0.32-0.91 after adjusting for maternal race/ethnicity, education, child sex, OR 0.55; 95% CI, 0.33-0.93 after adjusting for BMI, gestational weight gain, gestational diabetes, and smoking status). Maternal leptin and cord blood leptin and adiponectin levels were not associated with ASDs.

CONCLUSION

Prepregnancy BMI and adiponectin during pregnancy may be useful as a tool to monitor the risk of autism. Increasing adiponectin levels prenatally may play a role in the prevention of ASDs.

Maternal immune activation and neuroinflammation in human neurodevelopmental disorders

Maternal health during pregnancy plays a major role in shaping health and disease risks in the offspring. The maternal immune activation hypothesis proposes that inflammatory perturbations in utero can affect fetal neurodevelopment, and evidence from human epidemiological studies supports an association between maternal inflammation during pregnancy and offspring neurodevelopmental disorders (NDDs). Diverse maternal inflammatory factors, including obesity, asthma, autoimmune disease, infection and psychosocial stress, are associated with an increased risk of NDDs in the offspring. In addition to inflammation, epigenetic factors are increasingly recognized to operate at the gene-environment interface during NDD pathogenesis. For example, integrated brain transcriptome and epigenetic analyses of individuals with NDDs demonstrate convergent dysregulated immune pathways. In this Review, we focus on the emerging human evidence for an association between maternal immune activation and childhood NDDs, including autism spectrum disorder, attention-deficit/hyperactivity disorder and Tourette syndrome. We refer to established pathophysiological concepts in animal models, including immune signalling across the placenta, epigenetic 'priming' of offspring microglia and postnatal immune-brain crosstalk. The increasing incidence of NDDs has created an urgent need to mitigate the risk and severity of these conditions through both preventive strategies in pregnancy and novel postnatal therapies targeting disease mechanisms.

Diet-induced dysbiosis of the maternal gut microbiome in early life programming of neurodevelopmental disorders

The maternal gut microbiome plays a critical role in fetal and early postnatal development, shaping fundamental processes including immune maturation and brain development, among others. Consequently, it also contributes to fetal programming of health and disease. Over the last decade, epidemiological studies and work in preclinical animal models have begun to uncover a link between dysbiosis of the maternal gut microbiome and neurodevelopmental disorders in offspring. Neurodevelopmental disorders are caused by both genetic and environmental factors, and their interactions; however, clinical heterogeneity, phenotypic variability, and comorbidities make identification of underlying mechanisms difficult. Among environmental factors, exposure to maternal obesity in utero confers a significant increase in risk for neurodevelopmental disorders. Obesogenic diets in humans, non-human primates, and rodents induce functional modifications in maternal gut microbiome composition, which animal studies suggest are causally related to adverse mental health outcomes in offspring. Here, we review evidence linking maternal diet-induced gut dysbiosis to neurodevelopmental disorders and discuss how it could affect pre- and early postnatal brain development. We are hopeful that this burgeoning field of research will revolutionize antenatal care by leading to accessible prophylactic strategies, such as prenatal probiotics, to improve mental health outcomes in children affected by maternal diet-induced obesity.

Associations of Maternal Androgen-Related Conditions With Risk of Autism Spectrum Disorder in Progeny and Mediation by Cardiovascular, Metabolic, and Fertility Factors

Fetal exposure to elevated androgens is thought to contribute to autism spectrum disorder (ASD) risk. However, data rely heavily on in utero androgens measurements, which also reflect fetal secretions. Thus, in utero hyperandrogenemia might indicate adverse autism-related neurogenesis that has already occurred affecting fetal androgen homeostasis, rather than being a cause of the disorder. Associations between maternal androgen-related conditions and ASD could more directly implicate androgens' etiological role. We examined the association between maternal hyperandrogenemia-related conditions, focusing primarily on polycystic ovarian syndrome (PCOS), and progeny ASD, in an Israeli cohort of 437,222 children born in 1999-2013. Odds ratios and 95% confidence intervals were estimated using generalized estimating equations. Multiple mediation analyses using natural effect models were conducted to evaluate combined mediation of the PCOS effect by androgen-related cardiovascular, metabolic, and fertility factors. Results indicated that children of mothers with PCOS had higher ASD odds compared with children of mothers without PCOS (odds ratio = 1.42, 95% confidence interval: 1.24,1.64), and this effect was only partly mediated by the factors considered. Elevated odds were also observed for other hyperandrogenemia-related conditions. Findings provide support for direct involvement of maternal hyperandrogenemia in ASD etiology. Alternatively, findings might reflect shared genetic and/or environmental factors independently affecting maternal androgen homeostasis and fetal neurodevelopment.

Prenatal and perinatal metabolic risk factors for autism: a review and integration of findings from population-based studies

PURPOSE OF REVIEW

Given the ongoing rise in prevalence of autism spectrum disorder (ASD) and the challenges in developing and administering interventions to significantly alleviate ASD symptoms, there is an urgent need to identify modifiable risk factors for ASD. The goal of this review is to systematically evaluate the current evidence for an association between conditions related to maternal metabolic syndrome and risk for ASD in offspring focusing on methodically rigorous studies.

RECENT FINDINGS

In recent years, multiple studies explored the association between various conditions related to maternal metabolic syndrome (obesity, hypertension, or diabetes prior to, or with onset during pregnancy) and ASD risk in the offspring.

SUMMARY

Examining large, sufficiently powered, population-based epidemiological studies that explored the association between maternal metabolic syndrome and ASD, we found consistent evidence for an association between maternal preeclampsia and risk for ASD. Other conditions that are part of maternal metabolic syndrome, including maternal obesity, gestational weight gain, diabetes and gestational diabetes, should be studied further with careful attention paid to potential synergistic effects between different metabolic conditions. These findings highlight the need for rigorous, large, population-based epidemiological studies of potentially modifiable ASD risk factors that could inform public health interventions.

Crosstalk between maternal perinatal obesity and offspring dopaminergic circuitry

The mechanism by which maternal obesity influences fetal brain development and behavior is not well understood. In this issue of the JCI, Lippert et al. showed that feeding maternal mice a high-fat diet (HFD) during lactation attenuated the activity of dopamine (DA) midbrain neurons and altered the DA-related behavioral phenotype seen in the offspring. The authors further suggested that the altered excitatory and inhibitory balance between D1 medium spiny neurons (MSN) and D2 MSN mediates this behavioral phenotype. These mechanisms may provide strategies for preventing the negative effects of maternal obesity on offspring development and adult health.

Maternal acute and chronic inflammation in pregnancy is associated with common neurodevelopmental disorders: a systematic review

Inflammation is increasingly recognized as a cause or consequence of common problems of humanity including obesity, stress, depression, pollution and disease states such as autoimmunity, asthma, and infection. Maternal immune activation (MIA), triggered by both acute and systemic chronic inflammation, is hypothesized to be one of the mechanisms implicated in the pathogenesis of neurodevelopmental disorders (NDD). Although there is substantial preclinical evidence to support the MIA hypothesis, the human evidence is disparate. We performed a systematic review on human studies examining associations between maternal inflammatory states and offspring NDDs (autism spectrum disorder- ASD, attention deficit hyperactivity disorder-ADHD, Tourette syndrome-TS). 32 meta-analyses and 26 additional individual studies were identified. Maternal states associated with ASD include obesity, gestational diabetes mellitus, pre-eclampsia, pollution, stress, depression, autoimmune diseases, and infection. Maternal states associated with ADHD include obesity, pre-eclampsia, smoking, low socioeconomic status (SES), stress, autoimmune disease, and asthma. Maternal states associated with TS include low SES, depression, and autoimmune diseases. Diverse maternal inflammatory states in pregnancy are associated with common offspring NDDs. Given the increased prevalence of NDDs, there is urgent need to explore relative and cumulative maternal risk factors and disease mechanisms. Defining preventable risk factors in high-risk pregnancies could mitigate the expression and severity of NDDs.

Associations Among Maternal Metabolic Conditions, Cord Serum Leptin Levels, and Autistic Symptoms in Children

INTRODUCTION

Accumulating evidence has shown that maternal metabolic conditions, such as pre-pregnancy overweight, diabetes mellitus, and hypertensive disorders of pregnancy (HDP) are potential risk factors of autism spectrum disorder (ASD). However, it remains unclear how these maternal conditions lead to neurodevelopmental outcomes in the offspring, including autistic symptoms. Leptin, an adipokine that has pro-inflammatory effects and affects fetal neurodevelopment, is a candidate mediator of the association between maternal metabolic factors and an increased risk of ASD. However, whether prenatal exposure to leptin mediates the association between maternal metabolic conditions and autistic symptoms in children has not been investigated yet.

METHODS

This study investigated the associations between mothers' metabolic conditions (pre-pregnancy overweight, diabetes mellitus during or before pregnancy, and HDP), leptin concentrations in umbilical cord serum, and autistic symptoms among 762 children from an ongoing cohort study, using generalized structural equation modeling. We used the Social Responsive Scale, Second Edition (SRS-2) at 8-9 years old to calculate total T-scores. Additionally, we used the T-scores for two subdomains: Social Communication and Interaction (SCI) and Restricted Interests and Repetitive Behavior (RRB).

RESULTS

Umbilical cord leptin levels were associated with pre-pregnancy overweight [coefficient = 1.297, 95% confidence interval (CI) 1.081-1.556, p = 0.005] and diabetes mellitus (coefficient = 1.574, 95% CI 1.206-2.055, p = 0.001). Furthermore, leptin levels were significantly associated with SRS-2 total T-scores (coefficient = 1.002, 95% CI 1.000-1.004, p = 0.023), SCI scores (coefficient = 1.002, 95% CI 1.000-1.004, p = 0.020), and RRB scores (coefficient = 1.001, 95% CI 1.000-1.003, p = 0.044) in children. Associations between maternal metabolic factors and autistic symptoms were not significant.

DISCUSSION

The present study uncovered an association between cord leptin levels and autistic symptoms in children, while maternal metabolic conditions did not have an evident direct influence on the outcome. These results imply that prenatal pro-inflammatory environments affected by maternal metabolic conditions may contribute to the development of autistic symptoms in children. The findings warrant further investigation into the role of leptin in the development of autistic symptoms.

Association Study of MTHFR C677T Polymorphism and Birth Body Mass With Risk of Autism in Chinese Han Population

Objective: To explore the association of the methylenetetrahydrofolate reductase (MTHFR) C677T polymorphism with birth body mass and risk of autism in Chinese Han population. Methods: A total 1,505 Chinese Han autism patients were recruited, using the Diagnostic and Statistical Manual of Mental Disorders, 4th revised version (DSM-IV-R) diagnostic criteria for autism, and 1,308 sex-matched healthy controls were also enrolled for the study. All the participants' birth body masses were counted according to the medical records. The MTHFR C677T genotypes were detected using the polymerase chain reaction-restrict fragment length polymorphism (PCR-RFLP) method. The association between C677T polymorphism, birth body mass, and risk of autism were analyzed using the chi-square tests. Results: The present study found that the MTHFR 677T was significantly associated with risk of autism [P = 0.004, odds ratio (OR) = 1.18, 95% CI = 1.02-1.29). The autism children more frequently showed low birth body mass (<2.5 kg) than healthy control subjects (8.6 vs. 5.3%, P = 0.001, OR = 1.67, 95% CI = 1.24-2.26). The interactive effects between MTHFR 677T and low birth body mass (P = 0.0001, OR = 2.18, 95% CI = 1.44-3.32) were also significantly associated with risk of autism. Conclusions: The MTHFR C677T polymorphism and low birth body mass may be associated with risk of autism in Chinese Han population.

An Overview of the Main Genetic, Epigenetic and Environmental Factors Involved in Autism Spectrum Disorder Focusing on Synaptic Activity

Autism spectrum disorder (ASD) is a neurodevelopmental disorder that affects social interaction and communication, with restricted interests, activity and behaviors. ASD is highly familial, indicating that genetic background strongly contributes to the development of this condition. However, only a fraction of the total number of genes thought to be associated with the condition have been discovered. Moreover, other factors may play an important role in ASD onset. In fact, it has been shown that parental conditions and in utero and perinatal factors may contribute to ASD etiology. More recently, epigenetic changes, including DNA methylation and micro RNA alterations, have been associated with ASD and proposed as potential biomarkers. This review aims to provide a summary of the literature regarding ASD candidate genes, mainly focusing on synapse formation and functionality and relevant epigenetic and environmental aspects acting in concert to determine ASD onset.

Maternal Systemic Lupus Erythematosus, Rheumatoid Arthritis, and Risk for Autism Spectrum Disorders in Offspring: A Meta-analysis

This study assessed the relationships between maternal systemic lupus erythematosus (SLE) or rheumatoid arthritis (RA) and risk for autism spectrum disorders (ASDs) in offspring. Seven observational studies, including 25,005 ASD cases and 4,543,321 participants, were included for meta-analysis. Pooled results by using random-effects models suggested that maternal RA was associated with an increased risk for ASDs [odds ratio (OR) 1.39, 95% confidence interval (CI) 1.16-1.67], while maternal SLE was associated with an increased risk for ASDs only in western population (OR 1.91, 95% CI 1.02-3.57). Further study is warranted to confirm these results.

Maternal obesity modulates sexually dimorphic epigenetic regulation and expression of leptin receptor in offspring hippocampus

Maternal obesity during pregnancy is associated with a greater risk for obesity and neurodevelopmental deficits in offspring. This developmental programming of disease is proposed to involve neuroendocrine, inflammatory, and epigenetic factors during gestation that disrupt normal fetal brain development. The hormones leptin and insulin are each intrinsically linked to metabolism, inflammation, and neurodevelopment, which led us to hypothesise that maternal obesity may disrupt leptin or insulin receptor signalling in the developing brain of offspring. Using a C57BL/6 mouse model of high fat diet-induced maternal obesity (mHFD), we performed qPCR to examine leptin receptor (Lepr) and insulin receptor (Insr) gene expression in gestational day (GD) 17.5 fetal brain. We found a significant effect of maternal diet and offspring sex on Lepr regulation in the developing hippocampus, with increased Lepr expression in female mHFD offspring (p < 0.05) compared to controls. Maternal diet did not alter hippocampal Insr in the fetal brain, or Lepr or Insr in prefrontal cortex, amygdala, or hypothalamus of female or male offspring. Chromatin immunoprecipitation revealed decreased binding of histones possessing the repressive histone mark H3K9me3 at the Lepr promoter (p < 0.05) in hippocampus of female mHFD offspring compared to controls, but not in males. Sex-specific deregulation of Lepr could be reproduced in vitro by exposing female hippocampal neurons to the obesity related proinflammatory cytokine IL-6, but not IL-17a or IFNG. Our findings indicate that the obesity-related proinflammatory cytokine IL-6 during pregnancy leads to sexually dimorphic changes in the modifications of histones binding at the Lepr gene promoter, and concomitant changes to Lepr transcription in the developing hippocampus. This suggests that exposure of the fetus to metabolic inflammatory molecules can impact epigenetic regulation of gene expression in the developing hippocampus.

Bridging the Gap Between Physical Health and Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a highly complex and heterogeneous developmental disorder that affects how individuals communicate with other people and relate to the world around them. Research and clinical focus on the behavioural and cognitive manifestations of ASD, whilst important, have obscured the recognition that ASD is also commonly associated with a range of physical and mental health conditions. Many physical conditions appear with greater frequency in individuals with ASD compared to non-ASD populations. These can contribute to a worsening of social communication and behaviour, lower quality of life, higher morbidity and premature mortality. We highlight some of the key physical comorbidities affecting the immune and the gastrointestinal systems, metabolism and brain function in ASD. We discuss how healthcare professionals working with individuals with ASD and parents/carers have a duty to recognise their needs in order to improve their overall health and wellbeing, deliver equality in their healthcare experiences and reduce the likelihood of morbidity and early mortality associated with the condition.

Relationship of prenatal maternal obesity and diabetes to offspring neurodevelopmental and psychiatric disorders: a narrative review

Obesity and diabetes is a worldwide public health problem among women of reproductive age. This narrative review highlights recent epidemiological studies regarding associations of maternal obesity and diabetes with neurodevelopmental and psychiatric disorders in offspring, and provides an overview of plausible underlying mechanisms and challenges for future human studies. A comprehensive search strategy selected terms that corresponded to the domains of interest (maternal obesity, different types of diabetes, offspring cognitive functions and neuropsychiatric disorders). The databases searched for articles published between January 2010 and April 2019 were PubMed, Web of Science and CINAHL. Evidence from epidemiological studies strongly suggests that maternal pre-pregnancy obesity is associated with increased risks for autism spectrum disorder, attention-deficit hyperactivity disorder and cognitive dysfunction with modest effect sizes, and that maternal diabetes is associated with the risk of the former two disorders. The influence of maternal obesity on other psychiatric disorders is less well studied, but there are reports of associations with increased risks for offspring depression, anxiety, schizophrenia and eating disorders, at modest effect sizes. It remains unclear whether these associations are due to intrauterine mechanisms or explained by confounding family-based sociodemographic, lifestyle and genetic factors. The plausible underlying mechanisms have been explored primarily in animal models, and are yet to be further investigated in human studies.

Maternal obesity and long-term neuropsychiatric morbidity of the offspring

OBJECTIVE

To evaluate the long-term pediatric neuropsychiatric morbidity of children born to obese patients.

STUDY DESIGN

A population-based cohort analysis was performed comparing all deliveries of obese (maternal pre-pregnancy body mass index of 30 kg/m² or more) and non-obese patients between 1991 and 2014 at a single tertiary medical center. Hospitalizations of the offspring up to the age of 18 years involving neuropsychiatric morbidities were evaluated according to a pre-defined set of ICD-9 codes, including autistic, eating, sleeping and movement disorders, cerebral palsy, developmental disorders, and more. A Kaplan-Meier survival curve was used to compare cumulative hospitalization rate in exposed and unexposed offspring. A Cox regression model was used to control for confounders.

RESULTS

During the study period, 242,342 deliveries met the inclusion criteria. Of them, 3290 were children of obese mothers. Hospitalizations involving neuropsychiatric morbidities were higher in children born to obese mothers compared with those born to non-obese mothers (3.95% vs. 3.10%, p < 0.01). Specifically, offspring of obese mothers had higher rates of autism spectrum disorders and psychiatric disorders. The Kaplan-Meier survival curve demonstrated a significantly higher cumulative incidence of neuropsychiatric-related hospitalizations in the obese group (Fig. 1, log rank p < 0.05). Using a cox proportional hazard model, controlling for maternal age, preterm labor, maternal diabetes, hypertensive disorders of pregnancy, and birthweight, maternal obesity was found to be independently associated with long-term neuropsychiatric morbidity of the offspring (adjusted HR 1.24, 95% CI 1.04-1.47, p < 0.05).

CONCLUSION

Maternal obesity is an independent risk factor for long-term neuropsychiatric morbidity of the offspring.

Maternal Overweight, Inflammation and Neurological Consequences for the Preterm Child: Results of the ELGAN Study

Maternal overweight and obesity are prenatal risk factors for obstetrical complications, preterm birth, neonatal morbidity as well as cognitive and behavioural developmental disorders in children. Paediatric morbidity and mortality as well as child development disorders are significantly associated with maternal obesity. Particularly in the neurodevelopmental and psychiatric area, it is becoming increasingly clear that, in children of mothers with an increased body mass index (BMI), there is a high correlation with childhood cognitive disabilities, attention disorders, and diseases on the autistic spectrum. The ELGAN (Extremely Low Gestational Age Newborn) study is a multicentre study which has been supported since 2000 by the National Institutes of Health (NIH) and whose objective is to research predictors for neonatal brain damage and neurological-cognitive sequelae in premature infants. The areas of focus are the connection between maternal overweight and obesity and pregnancy complications, APGAR scores and systemic inflammatory markers. In this overview, our aim is to summarise the work in this area and discuss it critically on the basis of current literature. We will examine the hypothesis whether maternal overweight and obesity in terms of a chronic inflammatory state is associated with neonatal inflammation which in turn is associated with an unfavourable development prognosis.

Association of Genetic and Environmental Factors With Autism in a 5-Country Cohort

IMPORTANCE

The origins and development of autism spectrum disorder (ASD) remain unresolved. No individual-level study has provided estimates of additive genetic, maternal, and environmental effects in ASD across several countries.

OBJECTIVE

To estimate the additive genetic, maternal, and environmental effects in ASD.

DESIGN, SETTING, AND PARTICIPANTS

Population-based, multinational cohort study including full birth cohorts of children from Denmark, Finland, Sweden, Israel, and Western Australia born between January 1, 1998, and December 31, 2011, and followed up to age 16 years. Data were analyzed from September 23, 2016 through February 4, 2018.

MAIN OUTCOMES AND MEASURES

Across 5 countries, models were fitted to estimate variance components describing the total variance in risk for ASD occurrence owing to additive genetics, maternal, and shared and nonshared environmental effects.

RESULTS

The analytic sample included 2 001 631 individuals, of whom 1 027 546 (51.3%) were male. Among the entire sample, 22 156 were diagnosed with ASD. The median (95% CI) ASD heritability was 80.8% (73.2%-85.5%) for country-specific point estimates, ranging from 50.9% (25.1%-75.6%) (Finland) to 86.8% (69.8%-100.0%) (Israel). For the Nordic countries combined, heritability estimates ranged from 81.2% (73.9%-85.3%) to 82.7% (79.1%-86.0%). Maternal effect was estimated to range from 0.4% to 1.6%. Estimates of genetic, maternal, and environmental effects for autistic disorder were similar with ASD.

CONCLUSIONS AND RELEVANCE

Based on population data from 5 countries, the heritability of ASD was estimated to be approximately 80%, indicating that the variation in ASD occurrence in the population is mostly owing to inherited genetic influences, with no support for contribution from maternal effects. The results suggest possible modest differences in the sources of ASD risk between countries.

Environmental risk factors and biomarkers for autism spectrum disorder: an umbrella review of the evidence

BACKGROUND

Numerous studies have identified potential risk factors and biomarkers for autism spectrum disorder. We aimed to study the strength and validity of the suggested environmental risk factors or biomarkers of autism spectrum disorder.

METHODS

We did an umbrella review and systematically appraised the relevant meta-analyses of observational studies. We searched PubMed, Embase, and the Cochrane Database of Systematic Reviews for papers published between database inception and Oct 17, 2018, and screened the reference list of relevant articles. We obtained the summary effect, 95% CI, heterogeneity, and 95% prediction intervals. We examined small study effects and excess significance. We did analyses under credibility ceilings. This review is registered with PROSPERO, number CRD42018091704.

FINDINGS

46 eligible articles yielded data on 67 environmental risk factors (544 212 cases, 81 708 787 individuals) and 52 biomarkers (15 614 cases, 15 433 controls). Evidence of association was convincing for maternal age of 35 years or over (relative risk [RR] 1·31, 95% CI 1·18-1·45), maternal chronic hypertension (odds ratio [OR] 1·48, 1·29-1·70), maternal gestational hypertension (OR 1·37, 1·21-1·54), maternal overweight before or during pregnancy (RR 1·28, 1·19-1·36), pre-eclampsia (RR 1·32, 1·20-1·45), prepregnancy maternal antidepressant use (RR 1·48, 1·29-1·71), and maternal selective serotonin reuptake inhibitor (SSRI) use during pregnancy (OR 1·84, 1·60-2·11). Only two associations, maternal overweight before or during pregnancy and SSRI use during pregnancy, retained their high level of evidence under subset sensitivity analyses. Evidence from biomarkers was scarce, being supported by p values close to the significance threshold and too few cases.

INTERPRETATION

Convincing evidence suggests that maternal factors, such as age and features of metabolic syndrome, are associated with risk of autism spectrum disorder. Although SSRI use during pregnancy was also associated with such risk when exposed and non-exposed groups were compared, this association could be affected by other confounding factors, considering that prepregnancy maternal antidepressant use was also convincingly associated with higher risk of autism spectrum disorder. Findings from previous studies suggest that one possible confounding factor is underlying maternal psychiatric disorders.

FUNDING

None.

Impact of parental over- and underweight on the health of offspring

Parental excess weight and especially pregestational maternal obesity and excessive weight gain during pregnancy have been related to an increased risk of metabolic (obesity, type 2 diabetes, cardiovascular disease, metabolic syndrome) and nonmetabolic (cancer, osteoporosis, asthma, neurologic alterations) diseases in the offspring, probably mediated by epigenetic mechanisms of fetal programming. Maternal underweight is less common in developed societies, but the discrepancy between a poor nutritional environment in utero and a normal or excessive postnatal food supply with rapid growth catch-up appears to be the main candidate mechanism of the development of chronic diseases during the offspring's adulthood. The role of the postnatal environment in both scenarios (parental overweight or underweight) also seems to influence the offspring's health. Lifestyle interventions before and during pregnancy in both parents, but especially in the mother, as well as in children after birth, are advisable to counteract the many undesirable chronic conditions described.

Neurological Diseases With Autism Spectrum Disorder: Role of ASD Risk Genes

Autism spectrum disorder (ASD) is frequently comorbid with other neurological disorders such as intellectual disability (ID) or global development delay (GDD) and epilepsy. The pathogenesis of ASD is complex. So far, studies have identified more than 1000 ASD risk genes. Most of them were also reported to relate with other neurological diseases, and only several of them have been confirmed as pathogenic genes for autism. Little is known about the roles of these risk genes in neurological diseases with ASD. In the present study, we recruited a cohort of 158 neurological disorder probands with 163 variants of 48 ASD risk genes. Of these, 50 individuals (31.6%) were diagnosed with ASD. In the ASD patient subset, we identified several rarely reported candidate genes including DOLK, USH2A, and HUWE1. In a comparison of patients with neurological disorders with and without ASD, we found that ID/GDD was frequently comorbid with ASD whereas epilepsy was more common in the non-ASD group. Statistical analyses of all possible risk factors implicated that variants in synaptic genes, especially non-voltage-gated ion channel genes and in transcriptional and chromosome genes were related to ASD, but none of the investigated environmental factors was. Our results are useful for the future diagnosis and prognosis of patients with neurological disorders and emphasize the utility of genetic screening.

Maternal obesity and risk of cerebral palsy in children: a systematic review and meta-analysis

AIM

Several studies have examined the links between maternal obesity and the risk of cerebral palsy (CP) in children, with inconsistent results. The aim of our study was to investigate whether maternal obesity is associated with increased risk of CP in offspring by using meta-analysis.

METHOD

PubMed and Web of Science were searched until August 2017. Observational studies relevant to the maternal obesity and risk of CP in children were extracted and compiled. Meta-analyses were performed for different obesity levels and pooled odds ratios (ORs) and 95% confidence intervals (CIs) were reported.

RESULTS

A total of five cohort studies involving 12 324 cases and 7 919 288 participants were included in our meta-analysis. The pooled crude and adjusted ORs (95% CIs) were 1.65 (1.38-1.98) and 1.51 (1.24-1.84) respectively. Additionally, the pooled OR (95% CI) for CP in offspring in relation to maternal obesity class I (body mass index [BMI] 30.0-34.9), class II (BMI 35.0-39.9), and class III (BMI≥40.0) compared with normal weight during prepregnancy or pregnancy was 1.31 (1.15-1.50), 1.65 (1.34-2.02), and 2.37 (1.91-2.94) respectively.

INTERPRETATION

This meta-analysis demonstrated that increasing grades of maternal obesity are associated with a higher risk of CP in offspring.

WHAT THIS PAPER ADDS

Meta-analysis demonstrates a significant positive association between maternal obesity and the risk of cerebral palsy (CP) in children. Subgroup analysis indicates that higher grades of maternal obesity are associated with increasing risk of CP.

Maternal chorioamnionitis and neurodevelopmental outcomes in preterm and very preterm neonates: A meta-analysis

Context

No consensus exists regarding the association between maternal chorioamnionitis and neurodevelopmental outcomes in preterm and very preterm neonates.

Objectives

To investigate whether maternal chorioamnionitis affects neurodevelopmental outcomes and to identify the factors that may explain these effects.

Data sources

We used Ovid Medline, EMBASE and Web of Science to conduct a meta-analysis of studies published in English before August 25, 2017, with titles or abstracts that discussed an association between maternal chorioamnionitis and mental/motor development.

Study selection

Among the 603 initially identified studies, we selected those that addressed an association between maternal chorioamnionitis and mental/motor development according to our preselected inclusion criteria as follows: (1) the study compared infants with and without exposure to maternal chorioamnionitis and (2) the neurodevelopmental outcome was followed up using the Bayley Scales of Infant Development 2^nd edition.

Data synthesis

Our meta-analysis included 10 studies. According to a random effect model, infants with maternal chorioamnionitis exposure had poorer mental development (d = -2.25 [95%CI, -4.33, -0.17], p<0.05) than infants without maternal chorioamnionitis, and infants with maternal clinical chorioamnionitis exposure had poorer motor development (d = -2.37 [95%CI, -4.62 to -0.12], p<0.05) than infants without maternal clinical chorioamnionitis exposure. Factors in the meta-analysis that showed differences between the two patient groups included an MDI assessment blinded to medical history, MDI assessment at the correct age, and time of the MDI assessment.

Conclusion

This study suggests that maternal chorioamnionitis may affect mental development in preterm and very preterm neonates, and that maternal clinical chorioamnionitis may affect motor development in offspring. Further studies are required to confirm these results and to detect the influence of variables across studies.

Maternal smoking and high BMI disrupt thyroid gland development

BACKGROUND

Maternal lifestyle factors, including smoking and increased body weight, increase risks of adult diseases such as metabolic syndrome and infertility. The fetal thyroid gland is essential for the control of fetal metabolic rate, cardiac output, and brain development. Altered fetal thyroid function may contribute to increased disease onset later in life. Here, we investigated the impact of maternal smoking and high maternal weight on human fetal thyroid function during the second trimester.

METHODS

Thyroid glands and plasma were collected from fetuses electively terminated in the second trimester (normally progressing pregnancies). Plasma total triiodothyronine (T3) and total thyroxine (T4) were measured by solid-phase extraction-liquid chromatography-tandem mass spectrometry. Fetal plasma thyroid-stimulating hormone (TSH) levels were measured using a multiplex assay for human pituitary hormones. Histology and immunolocalization of thyroid developmental markers were examined in thyroid sections. Transcript levels of developmental, functional, apoptotic, and detoxification markers were measured by real-time PCR. Statistical analyses were performed using multivariate linear regression models with fetal age, sex, and maternal smoking or maternal body mass index (BMI) as covariates.

RESULTS

Maternal smoking was associated with significant changes in fetal plasma T4 and TSH levels during the second trimester. Smoke-exposed thyroids had reduced thyroid GATA6 and NKX2-1 transcript levels and altered developmental trajectories for ESR2 and AHR transcript levels. Maternal BMI > 25 was associated with increased fetal thyroid weight, increased plasma TSH levels, and abnormal thyroid histology in female fetuses. Normal developmental changes in AHR and ESR1 transcript expression were also abolished in fetal thyroids from mothers with BMI > 25.

CONCLUSIONS

For the first time, we show that maternal smoking and high maternal BMI are associated with disturbed fetal thyroid gland development and endocrine function in a sex-specific manner during the second trimester. These findings suggest that predisposition to post-natal disease is mediated, in part, by altered fetal thyroid gland development.

Association between maternal overweight or obesity and cerebral palsy in children: A meta-analysis

CONTEXT

There is no consensus regarding the association between maternal obesity or overweight and cerebral palsy (CP) in children.

OBJECTIVES

To investigate whether maternal obesity or overweight is associated with CP and identify the factors that explain the differences in the study results.

DATA SOURCES

We conducted a meta-analysis of studies published in English with titles or abstracts that discussed the relationships between maternal obesity or overweight and CP before August 23, 2017, using Ovid Medline, EMBASE and Web of Science.

STUDY SELECTION

Of 2699 initially identified studies, 8 studies that addressed the association between maternal obesity and CP met our final inclusion criteria.

DATA EXTRACTION

Information from the individual studies was abstracted using standardized forms by 2 independent observers who were blinded to the authors' names and journal titles.

DATA SYNTHESIS

According to a random effects model, maternal overweight was significantly associated with CP in offspring [RR = 1.29 (95% CI, 1.04-1.60), heterogeneity (I2 = 45.5%, P = 0.103)]; maternal obesity was significantly associated with CP in offspring [RR = 1.45 (95% CI, 1.25-1.69), heterogeneity (I2 = 24.1%, P = 0.253)]; and maternal obesity III was significantly associated with CP in offspring [RR = 2.25 (95% CI, 1.82-2.79), heterogeneity (I2 = 0%, P = 0.589)]. However, maternal underweight was not significantly associated with CP in offspring [RR = 1.11 (95% CI, 0.88-1.38), low heterogeneity (I2 = 0%, P = 0.435)]. Factors that explained the differences in the meta-analysis results included study design, study location, and whether individual studies adjusted for potential confounders.

CONCLUSION

This study suggests that maternal obesity and overweight increase the risk of CP in offspring. Further studies are required to confirm these results and determine the influence of variables across studies.

Association between bronchopulmonary dysplasia and cerebral palsy in children: a meta-analysis

OBJECTIVE

To investigate the association between bronchopulmonary dysplasia (BPD) and the risk of cerebral palsy (CP) in children.

DATA SOURCES

We used EMBASE, PubMed and Web of Science to conduct a meta-analysis of studies published before 1 September 2017, written in English whose titles or abstracts discussed an association between BPD and CP.

STUDY SELECTION

Observational studies, for example, case-control and cohort studies were included.

DATA EXTRACTION AND SYNTHESIS

All review stages were conducted by two reviewers independently. Data synthesis was undertaken via meta-analysis of available evidence.

MAIN OUTCOMES AND MEASURES

The prevalence of developing CP was measured after exposure to BPD.

RESULTS

Among 1234 initially identified studies, we selected those that addressed an association between BPD and CP according to our preselected inclusion criteria. Our meta-analysis included 11 studies. According to a random effect model, BPD was significantly associated with CP (ORs 2.10; 95% CI 1.57 to 2.82) in preterm infants. Factors explaining differences in the study results included study design, the definition of BPD, the time of diagnosis of CP and whether the studies adjusted for potential confounders.

CONCLUSION

This study suggests that BPD is a risk factor for CP. Further studies are required to confirm these results and to detect the influence of variables across studies.

Maternal pre-pregnancy weight and autistic-like traits among offspring in the general population

There is an emerging body of evidence demonstrating that maternal obesity at the time of conception increases the risk for Autism Spectrum Disorders (ASD) among offspring. We explored whether pre-pregnancy weight was related to autistic-like traits among offspring not diagnosed with ASD. A large sample of women, recruited during the second trimester of pregnancy, had their height measured and reported their pre-pregnancy weight. These measurements were then converted to a Body Mass Index (BMI) using the formula: (weight in kilograms)/(height in metres² ). At 19-20 years of age, 1238 offspring of these women completed a measure of autistic-like traits, the Autism-Spectrum Quotient (AQ). Regression analyses identified a positive association between increasing maternal pre-pregnancy BMI and increasing AQ Total Score amongst offspring; this association was maintained even after controlling for a range of variables including maternal/obstetric factors (age at conception, education, smoking, alcohol consumption, hypertensive diseases, diabetes, threatened abortion), paternal BMI at pregnancy, and child factors (parity, sex) (P < .01, R² =.03). Chi-square analyses found that women with pre-pregnancy obesity (BMI ≥ 30) were more likely to have offspring with high scores (≥26) on the AQ (P = .01). Follow-up binary logistic regression analyses also accounting for the same obstetric and sociodemographic variables found that the offspring of women with pre-pregnancy obesity were at a statistically significantly increased risk of having high scores (≥26) on the AQ (OR: 2.80; 95% CI: 1.06, 7.43). This study provides further evidence that maternal pre-pregnancy obesity is associated with autism-like behaviors in offspring. Autism Research 2019, 12: 80-88. © 2018 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: The current study explored whether pre-pregnancy weight was related to autistic-like traits among offspring not diagnosed with ASD. We found that pre-pregnancy body mass index in women is associated with the amount of autistic-like traits in their children in early adulthood. Specifically, women who were obese at the time of conception were more likely to have a child who had high levels of autistic-like traits in early adulthood.

The adipocyte hormone leptin sets the emergence of hippocampal inhibition in mice

Brain computations rely on a proper balance between excitation and inhibition which progressively emerges during postnatal development in rodent. γ-Aminobutyric acid (GABA) neurotransmission supports inhibition in the adult brain but excites immature rodent neurons. Alterations in the timing of the GABA switch contribute to neurological disorders, so unveiling the involved regulators may be a promising strategy for treatment. Here we show that the adipocyte hormone leptin sets the tempo for the emergence of GABAergic inhibition in the newborn rodent hippocampus. In the absence of leptin signaling, hippocampal neurons show an advanced emergence of GABAergic inhibition. Conversely, maternal obesity associated with hyperleptinemia delays the excitatory to inhibitory switch of GABA action in offspring. This study uncovers a developmental function of leptin that may be linked to the pathogenesis of neurological disorders and helps understanding how maternal environment can adversely impact offspring brain development.

Maternal cytomegalovirus sero-positivity and autism symptoms in children

PROBLEM

Autism spectrum disorder (ASD) is one of the most commonly diagnosed neurodevelopmental disorders in the United States. While ASD can be significantly influenced by genetics, prenatal exposure to maternal infections has also been implicated in conferring risk. Despite this, the effects of several important maternal pathogens, such as cytomegalovirus (CMV) and herpes simplex virus 2 (HSV2), remain unknown.

METHOD OF STUDY

We tested whether maternal CMV and/or HSV2 sero-positivity was associated with ASD symptoms in children. ELISA was used to assay for CMV IgG and HSV2 IgG in serum from the mothers of 82 children whose ASD symptoms were assessed at 3-6 years of age using the Social Responsiveness Scale version 2 (SRS-2).

RESULTS

Associations between maternal viral serostatus and SRS-2 scores were estimated using linear regression with covariate adjustments. The children of mothers sero-positive for CMV, but not for HSV2, had SRS-2 scores 3.6-4.2 points higher, depending on the adjustment model, than sero-negative women, a significant finding, robust to several statistical adjustments.

CONCLUSION

Our results suggest that maternal CMV infections may influence ASD symptoms. These findings are being further evaluated in ongoing prospective studies with larger population samples.

[Association between overweight/obesity in parents and autism spectrum disorders in offspring]

OBJECTIVE

To study the association between overweight/obesity in parents before maternal pregnancy and the development of autism spectrum disorders (ASD) in offspring.

METHODS

A total of 36 children who were diagnosed with ASD (ASD group) and 72 normal children matched for sex and age (control group) were enrolled. A questionnaire survey was performed to collect the general information, including body height and body weight of parents before maternal pregnancy and maternal weight gain during pregnancy. Univariate and multivariate logistic regression analyses were used to investigate the association between overweight/obesity in parents before maternal pregnancy and ASD in offspring.

RESULTS

The ASD group had a significantly higher detection rate of overweight/obesity in the father than the control group (56% vs 32%; P=0.018) before maternal pregnancy. The univariate and multivariate logistic regression analyses showed that overweight/obesity of the father before maternal pregnancy was a risk factor for ASD in offspring (OR=2.66 and 2.58 respectively; P<0.05).

CONCLUSIONS

Overweight/obesity of the father before maternal pregnancy is an independent risk factor for ASD in offspring, and therefore, it is important for the father to control his body mass index within the normal range before maternal pregnancy.

[Association between overweight/obesity in parents and autism spectrum disorders in offspring]

OBJECTIVE

To study the association between overweight/obesity in parents before maternal pregnancy and the development of autism spectrum disorders (ASD) in offspring.

METHODS

A total of 36 children who were diagnosed with ASD (ASD group) and 72 normal children matched for sex and age (control group) were enrolled. A questionnaire survey was performed to collect the general information, including body height and body weight of parents before maternal pregnancy and maternal weight gain during pregnancy. Univariate and multivariate logistic regression analyses were used to investigate the association between overweight/obesity in parents before maternal pregnancy and ASD in offspring.

RESULTS

The ASD group had a significantly higher detection rate of overweight/obesity in the father than the control group (56% vs 32%; P=0.018) before maternal pregnancy. The univariate and multivariate logistic regression analyses showed that overweight/obesity of the father before maternal pregnancy was a risk factor for ASD in offspring (OR=2.66 and 2.58 respectively; P&lt;0.05).

CONCLUSIONS

Overweight/obesity of the father before maternal pregnancy is an independent risk factor for ASD in offspring, and therefore, it is important for the father to control his body mass index within the normal range before maternal pregnancy.