Anesthesia, sex and miscarriage history may influence the association between cesarean delivery and autism spectrum disorder

Childhood anaesthesia and autism risk: population and murine study

Early childhood exposure to general anaesthesia has been linked to potential changes in infant brain morphology and behaviour in preclinical studies, contributing to long-term behaviours associated with autism spectrum disorder. This study investigates the association between early childhood exposure to general anaesthesia and the risk of autism, using a population-based cohort study with matching for baseline characteristics and evaluates the effect of sevoflurane exposure on autism-like behaviour in mice, using the Taiwan Maternal and Child Health Database. Children aged 0-3 who received at least one exposure to general anaesthesia between 2004 and 2014 were matched 1:1 with children who were not exposed. Risk ratios and confidence intervals were used to assess the relationship between general anaesthesia and the occurrence of autism. Additionally, mice were exposed to sevoflurane for 2 h on postnatal days 5-7, and changes in behaviour related to autism were evaluated. Propensity score matching resulted in 7530 children in each group. The incidence rates (IRs) of autism were 11.26 and 6.05 per 100 000 person-years in the exposed and unexposed groups, respectively. The incidence ratio for autism following exposure to general anaesthesia was 1.86 (95% confidence interval, 1.34-2.59). In mice, sevoflurane exposure induced autism-like behaviours and led to the downregulation of high-risk autism genes, including ARID1B, GABRA5, GABRB3, GRIN2B, SHANK3 and SUV420H1. Early childhood exposure to general anaesthesia is associated with an increased risk of autism. Repeated exposure to sevoflurane in mice induces autism-like behaviours, suggesting a potential link between anaesthesia and the development of autism.

Between Dysbiosis, Maternal Immune Activation and Autism: Is There a Common Pathway?

Autism spectrum disorder (ASD) is a neuropsychiatric condition characterized by impaired social interactions and repetitive stereotyped behaviors. Growing evidence highlights an important role of the gut-brain-microbiome axis in the pathogenesis of ASD. Research indicates an abnormal composition of the gut microbiome and the potential involvement of bacterial molecules in neuroinflammation and brain development disruptions. Concurrently, attention is directed towards the role of short-chain fatty acids (SCFAs) and impaired intestinal tightness. This comprehensive review emphasizes the potential impact of maternal gut microbiota changes on the development of autism in children, especially considering maternal immune activation (MIA). The following paper evaluates the impact of the birth route on the colonization of the child with bacteria in the first weeks of life. Furthermore, it explores the role of pro-inflammatory cytokines, such as IL-6 and IL-17a and mother's obesity as potentially environmental factors of ASD. The purpose of this review is to advance our understanding of ASD pathogenesis, while also searching for the positive implications of the latest therapies, such as probiotics, prebiotics or fecal microbiota transplantation, targeting the gut microbiota and reducing inflammation. This review aims to provide valuable insights that could instruct future studies and treatments for individuals affected by ASD.

Effect of cesarean section on the risk of autism spectrum disorders/attention deficit hyperactivity disorder in offspring: a meta-analysis

PURPOSE

This study was conducted to investigate the relationship between cesarean section (CS) offspring and autism spectrum disorders (ASD)/attention deficit hyperactivity disorder (ADHD).

METHODS

Searching of the databases (PubMed, Web of Science, Embase, and Cochrane Library) for studies on the relationship between mode of delivery and ASD/ADHD until August 2022. The primary outcome was the incidence of ASD/ADHD in the offspring.

RESULTS

This meta-analysis included 35 studies (12 cohort studies and 23 case-control studies). Statistical results showed a higher risk of ASD (odds ratio (OR) = 1.25, P < 0.001) and ADHD (OR = 1.11, P < 0.001) in CS offspring compared to the VD group. Partial subgroup analysis showed no difference in ASD risk between CS and VD offspring in sibling-matched groups (OR = 0.98, P = 0.625). The risk of ASD was higher in females (OR = 1.66, P = 0.003) than in males (OR = 1.17, P = 0.004) in the CS offspring compared with the VD group. There was no difference in the risk of ASD between CS under regional anesthesia group and VD group (OR = 1.07, P = 0.173). However, the risk of ASD was higher in the CS offspring under general anesthesia than in the VD offspring (OR = 1.62, P < 0.001). CS offspring developed autism (OR = 1.38, P = 0.011) and pervasive developmental disorder-not otherwise specified (OR = 1.46, P = 0.004) had a higher risk than VD offspring, but there was no difference in Asperger syndrome (OR = 1.19, P = 0.115). Offspring born via CS had a higher incidence of ADHD in different subgroup analyses (sibling-matched, type of CS, and study design).

CONCLUSIONS

In this meta-analysis, CS was a risk factor for ASD/ADHD in offspring compared with VD.

Association between Cesarean section and neurodevelopmental disorders in a Japanese birth cohort: the Japan Environment and Children's Study

BACKGROUND

The long-term effects of a Cesarean section (CS) birth on child neurodevelopment are of increasing interest. In this study, we examined the associations between mode of delivery and presence of neurodevelopmental disorders in toddlers. Moreover, given that the prevalence of several neurodevelopmental disorders such as autism spectrum disorder (ASD) is known to differ by sex, we also investigated these associations separately in male and female toddlers.

METHODS

We investigated 65,701 mother-toddler pairs from the Japan Environment and Children's Study, a nationally representative children's cohort study. To investigate the associations between mode of delivery (CS or vaginal delivery) and neurodevelopmental disorders (motor delay, intellectual disability, and ASD) in 3-year-old toddlers as a whole and stratified by sex, we used logistic regression models to calculate adjusted odds ratios (aORs) with 95% confidence intervals (CIs).

RESULTS

The morbidity of ASD at age 3 years was higher for children delivered by CS than those delivered vaginally (aOR 1.38, 95% CI 1.04-1.83). However, no such difference was evident in the case of motor delay or intellectual disability (aOR 1.33, 95% CI 0.94-1.89; aOR 1.18, 95% CI 0.94-1.49, respectively). In the analysis by sex, CS was not associated with increased risk of any of the neurodevelopmental disorders in males, but it was associated with increased risks of motor delay (aOR 1.88, 95% CI 1.02-3.47) and ASD (aOR 1.82, 95% CI 1.04-3.16) in females.

CONCLUSIONS

This study provides evidence of significant associations between mode of delivery and neurodevelopmental disorders in early childhood. Females may be more sensitive to the effects of CS than males.

Association between previous abortion history and risk of autism spectrum disorders among offspring: a meta-analysis

BACKGROUND

Previous studies have been showed an association between previous abortion history and risk of Autism spectrum disorders (ASD). However, there is still controversy about true effect estimate of the association.

PURPOSE

This meta-analysis aimed to evaluate the association between previous abortion history and the risk of ASD.

METHODS

A systematic search was performed using PubMed, Scopus, and Web of Sciences databases to identify potential studies published until December 2021. The presence of statistical heterogeneity was determined using the I2 value. In the case of substantial heterogeneity, the random-effects model meta-analysis was used to estimate the pooled relative risks. The publication bias was assessed using the Egger and Begg tests.

RESULTS

Thirteen studies with a total of 331,779 children remained in the present meta-analysis. The estimated odds ratio of the risk of ASD associated with previous abortion history was 1.64 (95% confidence interval [CI], 1.28-2.0; I2=61.7%) in adjusted studies and 1.10 (95% CI, 1.01-1.20; I2=0.0%) in crude studies, based on the random effect model. There was moderate heterogeneity in adjusted studies. The p values for Egger and Begg regression among children with ASD were 0.393 and 0.056, respectively.

CONCLUSION

This meta-analysis suggests that children born from mothers with a history of previous abortion have an increased risk of development of ASD compared to children of mothers without a history of previous abortion.

Beyond Genes: Germline Disruption in the Etiology of Autism Spectrum Disorders

Investigations into the etiology of autism spectrum disorders have been largely confined to two realms: variations in DNA sequence and somatic developmental exposures. Here we suggest a third route-disruption of the germline epigenome induced by exogenous toxicants during a parent's gamete development. Similar to cases of germline mutation, these molecular perturbations may produce dysregulated transcription of brain-related genes during fetal and early development, resulting in abnormal neurobehavioral phenotypes in offspring. Many types of exposures may have these impacts, and here we discuss examples of anesthetic gases, tobacco components, synthetic steroids, and valproic acid. Alterations in parental germline could help explain some unsolved phenomena of autism, including increased prevalence, missing heritability, skewed sex ratio, and heterogeneity of neurobiology and behavior.

A National Population Cohort Study Showed That Exposure to General Anesthesia in Early Childhood Is Associated with an Increase in the Risk of Developmental Delay

This study investigated the relationship between exposure to general anesthesia (GA) and the risk of cognitive and mental disorders. This study has thus investigated the relationships between exposure to GA before the age of 3 and subsequent cognitive and mental disorders in a national-wide research sample. We obtained our subjects from the National Health Insurance Research Database (NHIRD) of Taiwan, which was based on the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). Children in the hospital aged less than 3 years old were included if there was GA exposure or not during the period of year 1997 to 2008. Cox proportional hazard regression models adjusted for potential confounding factors were used to estimate the relative magnitude of the risk associated with GA exposure. The cohort contained 2261 subjects with GA and 4522 children without GA as a comparison group. GA exposure group had a higher rate of developmental delay than in the without GA group (hazard ratio 1.46, p < 0.0001). There was no significant difference in the overall incidence of ADHD, autism and intellectual disability between the GA-exposed group and the comparison cohort. In conclusion, this study reported that children exposed to GA early before the age of three had a small association with increased risk of development delay thereafter.