Elective Deliveries and the Risk of Autism

Regional differences in autism and intellectual disability risk associated with cesarean section delivery

Prior epidemiological studies investigating the association between delivery mode (i.e., vaginal birth and cesarean section [C-section]) and autism spectrum disorder (ASD) and intellectual disability (ID) risk have reported mixed findings. This study examined ASD and ID risks associated with primary and repeat C-section within diverse US regions. During even years 2000-2016, 8-years-olds were identified with ASD and/or ID and matched to birth records [ASD only (N = 8566, 83.6% male), ASD + ID (N = 3445, 79.5% male), ID only (N = 6158, 60.8% male)] using the Centers for Disease Control and Prevention's Autism and Developmental Disabilities Monitoring Network methodology. The comparison birth cohort (N = 1,456,914, 51.1% male) comprised all births recorded in the National Center for Health Statistics corresponding to birth years and counties in which surveillance occurred. C-section rates in the birth cohort demonstrated significant regional variation with lowest rates in the West. Overall models demonstrate increased odds of disability associated with primary and repeat C-section. Adjusted models, stratified by region, identified significant variability in disability likelihood associated with repeat C-section: increased odds occurred for all case groups in the Southeast, for ASD only and ID only in the Mid-Atlantic, and no case groups in the West. Regional variability in disability risk associated with repeat C-section coincides with differences in birth cohorts' C-section rates. This suggests increased likelihood of disability is not incurred by the procedure itself, but rather C-section serves as a proxy for exposures with regional variability that influence fetal development and C-section rates.

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.

Trends in Elective Deliveries in California and New Jersey

Introduction

Cesarean section deliveries in the U.S. increased from 5% of births in 1970 to 32% in 2020. Little is known about trends in cesarean sections and inductions in low-risk pregnancies (i.e., those for which interventions would not be medically necessary). This study addresses the following questions: (1) what is the prevalence of elective deliveries at the population level?, (2) how has that changed over time?, and (3) to what extent do the rates of elective deliveries vary across the population?

Methods

We first documented long-term trends in cesarean sections in the U.S., California, and New Jersey. We then used linked birth and hospital discharge records and an algorithm based on Joint Commission guidelines to identify low-risk pregnancies and document trends in cesarean sections and inductions in low-risk pregnancies in California and New Jersey over a recent 2-decade period, overall and by maternal characteristics and gestational age.

Results

In low-risk pregnancies in California and New Jersey, rates of cesarean sections and inductions increased sharply from the early 1990s through the mid-2000s, peaked at 33% in California and 41% in New Jersey in 2007, and then declined somewhat, and the proportions of inductions that were followed by cesarean sections increased from fewer than 1 in 5 to about 1 in 4. More education, non-Hispanic White race/ethnicity, U.S.-born status, and non-Medicaid were associated with higher rates of interventions. Trends were similar across all socioeconomic groups, but differences have been narrowing in California. Among early-term (gestational age of 37-38 weeks) births in low-risk pregnancies, the rates of elective deliveries increased substantially in both states until the mid/late-2000s, peaked at about 35% in California and over 40% in New Jersey, and then decreased in both states to about 20%.

Conclusions

Given established health risks of nonmedically necessary cesarean sections, that a nontrivial share of induced deliveries in low-risk pregnancies result in cesarean sections, and that interventions in low-risk pregnancies have not substantially declined since their peak in the mid-2000s, the trends documented in this paper suggest that sustained, even increased, public health attention is needed to address the still-too-high rates of cesarean sections and inductions in the U.S.