Does Autism Diagnosis Age or Symptom Severity Differ Among Children According to Whether Assisted Reproductive Technology was Used to Achieve Pregnancy?

Assessing the impact of medically assisted reproduction on autism spectrum disorder risk

PURPOSE

Techniques of medically assisted reproduction interact with the embryo at crucial developmental stages, yet their impact on the fetus and subsequent child's health remains unclear. Given rising infertility rates and more frequent use of fertility treatments, we aimed to investigate if these methods heighten the risk of autism spectrum disorder (ASD) in children.

METHODS

A population-based cohort study was conducted at Soroka University Medical Center, a tertiary referral hospital, encompassing singleton births. The incidence of ASD in offspring, incorporating either hospital or community-based diagnoses, was compared in relation to the conception method. To examine the cumulative incidence of ASD, a Kaplan-Meier survival curve was utilized. Cox proportional hazards model was employed to adjust for confounders.

RESULTS

Among 115,081 pregnancies, 0.5% involved ovulation induction (OI) and 1.7% in vitro fertilization (IVF), with the rest conceived naturally. Fertility treatments were more common in older patients and linked to more diabetes, hypertensive disorders, preterm, and cesarean deliveries. Out of 767 ASD diagnoses, offspring from OI and IVF had higher initial ASD rates (2.1% and 1.3%) than natural conceptions (0.6%). In a Cox model accounting for maternal age, ethnicity, and gender, neither OI nor IVF was significantly associated with ASD. The adjusted hazard ratios were 0.83 (95% CI 0.48-1.43) for OI and 1.34 (95% CI 0.91-1.99) for IVF. When considering fertility treatments combined, the association with ASD remained non-significant (aHR 1.11, 95% CI 0.80-1.54, p = 0.52).

CONCLUSION

Fertility treatments, including OI and IVF, do not exhibit a significant association with heightened ASD risk in offspring.

Assisted reproductive technology and neurodevelopment in children at 1 year of age: a longitudinal birth cohort study

BACKGROUND

With remarkable advancements in assisted reproductive technology (ART), the number of ART-conceived children continues to increase. Despite increased research investigating the outcomes of ART children, evidence on neurodevelopment remains controversial.

OBJECTIVE

The aim of this study was to investigate the association between ART use and neurodevelopment in children at 1 year of age and to determine whether the characteristics of parental infertility and specific ART procedures affect neurodevelopment in children.

STUDY DESIGN

The Jiangsu Birth Cohort enrolled couples who received ART treatment and who conceived spontaneously (2014-2020) in Jiangsu Province, China. In this study, we included 3531 pregnancies with 3840 cohort children who completed neurodevelopment assessment at 1 year of age, including 1906 infants conceived by ART (including 621 twins). Poisson regressions were fitted to estimate unadjusted and adjusted risk ratios (RRs) and 95% confidence intervals (CIs) for ART use with neurodevelopmental outcomes (cognition, receptive communication, expressive communication, fine motor, and gross motor) in children.

RESULTS

Among singletons, ART use was associated with a 24% to 34% decrease in the risk for noncompetent development in 3 domains (cognition, adjusted RR, 0.66; 95% CI, 0.53-0.82; receptive communication, 0.76; 0.64-0.91; expressive communication, 0.69; 0.51-0.93) after adjustment for conventional covariates. However, an inverse association was observed in the gross motor domain, with ART singletons having a greater risk of being noncompetent in gross motor development than their non-ART counterparts (adjusted RR, 1.41; 95% CI, 1.11-1.79). Compared with singletons, twins resulting from ART treatment demonstrated compromised neurodevelopment in several domains. Furthermore, we continued to observe that the transfer of 'poor' quality embryos was associated with greater risks for noncompetent development in receptive communication (adjusted RR, 1.50; 95% CI, 1.05-2.14) and gross motor domains (1.55; 1.02-2.36) among ART singletons.

CONCLUSION

These results generally provide reassuring evidence among singletons born after ART in the cognition, communication, and fine motor domains, but drawn attention to their gross motor development. The quality of transferred embryos in ART treatment might be associated with offspring neurodevelopment; however, the potential associations warrant further validation in independent studies, and the clinical significance needs careful interpretation.

Environmental Risk Factors in Autism Spectrum Disorder: A Narrative Review

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

Infertility treatment and autism risk using the Modified Checklist for Autism in Toddlers (M-CHAT)

STUDY QUESTION

Are toddlers conceived by fertility treatment at higher risk of failing a screening tool for autism spectrum disorders (ASD) than toddlers not conceived by treatment?

SUMMARY ANSWER

Compared with children not conceived by infertility treatment, children conceived by any infertility treatment, ovulation induction with or without intrauterine insemination (OI/IUI), or assisted reproductive technologies (ART) appeared to have had higher odds of failing an ASD screening; however, results were inconclusive and need replication.

WHAT IS KNOWN ALREADY

Although most of the studies which have examined risk of ASD after ART show no association, the results are mixed. Thus, further studies are needed to clarify this association.

STUDY DESIGN SIZE, DURATION

The Upstate KIDS Study is a population-based, prospective cohort study of children born in New York State between 2008 and 2010. Children were screened for ASD using the Modified Checklist for Autism in Toddlers (M-CHAT) at ages 18 and 24 months.

PARTICIPANTS/MATERIALS, SETTING, AND METHODS

The New York State live-birth registry was used to identify newborns conceived with and without fertility treatment with a 1:3 ratio, frequency matched on region of birth. At 18 and 24 months, 3183 and 3063 mothers, respectively, completed the M-CHAT questionnaire. The current analysis included 2586 singletons and 1296 twins with M-CHAT information at 18 and/or 24 months. Multivariable logistic regression with generalized estimating equations (GEE) was used to estimate odds ratios (aOR) and 95% confidence intervals (CI) after adjustment for covariates such as maternal age, education and plurality.

MAIN RESULTS AND THE ROLE OF CHANCE

We found that 200 (5.2%) and 115 (3.0%) children failed the M-CHAT at 18 and 24 months, respectively. The associations between use of infertility treatment and failing the M-CHAT at 18 and/or 24 months were positive but inconclusive as they failed to exclude no association (18 months aOR 1.71, 95% CI: 0.81-3.61; 24 months aOR 1.78, 95% CI: 0.66-4.81; and both 18 and 24 months aOR 1.53, 95% CI: 0.78-2.99). The relationships between OI/IUI and ART with M-CHAT failure at 18 and/or 24 months were similar to those of using any fertility treatment. In vitro fertilization with intracytoplasmic sperm injection was not consistently positively or inversely associated with M-CHAT failure at each time point (18 months aOR 1.20, 95% CI: 0.51-2.83; 24 months aOR 0.93, 95% CI: 0.37-2.31; and both 18 and 24 months aOR 1.09, 95% CI: 0.50-2.60).

LIMITATIONS REASONS FOR CAUTION

The M-CHAT is a screening tool used for ASD risk assessment, and therefore, M-CHAT failure does not indicate ASD diagnosis. In addition, we did not have power to detect associations of small magnitude. Finally, non-response to follow-up may bias the results.

WIDER IMPLICATIONS OF THE FINDINGS

Despite lack of precision, the positive associations between ART and M-CHAT failure suggest that larger population-based studies with longer follow-up are needed.

STUDY FUNDING/COMPETING INTEREST(S)

Supported by the Intramural Research Program of the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD; contracts HHSN275201200005C, HHSN267200700019C). The sponsor played no role in the study design, data collection, data analysis or interpretation, writing of the manuscript or decision to submit the article for publication. There are no conflicts of interest to declare.

TRIAL REGISTRATION NUMBER

Not applicable.

Maternal and Paternal Infertility Disorders and Treatments and Autism Spectrum Disorder: Findings from the Study to Explore Early Development

Previous studies of associations between ASD and conception using assisted reproductive technology (ART) are inconsistent and few studies have examined associations with other infertility treatments or infertility disorders. We examined associations between ASD and maternal/paternal infertility disorders and numerous maternal treatments among 1538 mother-child pairs in the Study to Explore Early Development, a population-based case-control study. ASD was associated with any female infertility diagnosis and several specific diagnoses: blocked tubes, endometriosis, uterine-factor infertility, and polycystic ovarian syndrome. Stratified analyses suggested associations were limited to/much stronger among second or later births. The findings were not explained by sociodemographic factors such as maternal age or education or multiple or preterm birth. ASD was not associated with ART or non-ART infertility treatments.

Epigenetics of Autism Spectrum Disorder

Autism spectrum disorder (ASD), one of the most common childhood neurodevelopmental disorders (NDDs), is diagnosed in 1 of every 68 children. ASD is incredibly heterogeneous both clinically and aetiologically. The etiopathogenesis of ASD is known to be complex, including genetic, environmental and epigenetic factors. Normal epigenetic marks modifiable by both genetics and environmental exposures can result in epigenetic alterations that disrupt the regulation of gene expression, negatively impacting biological pathways important for brain development. In this chapter we aim to summarize some of the important literature that supports a role for epigenetics in the underlying molecular mechanism of ASD. We provide evidence from work in genetics, from environmental exposures and finally from more recent studies aimed at directly determining ASD-specific epigenetic patterns, focusing mainly on DNA methylation (DNAm). Finally, we briefly discuss some of the implications of current research on potential epigenetic targets for therapeutics and novel avenues for future work.

The Changing Epidemiology of Autism Spectrum Disorders

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

Examining Infertility Treatment and Early Childhood Development in the Upstate KIDS Study

IMPORTANCE

An increasing percentage of births are conceived with assisted reproductive technology (ART) and other infertility treatment. Despite findings that such treatments may be associated with diminished gestation and birth size, scarce data exist regarding infertility treatments and children's development in the United States.

OBJECTIVE

To assess the use and type of infertility treatment in relation to children's development through age 36 months.

DESIGN, SETTING, AND PARTICIPANTS

Prospective cohort study (conducted 2008-2014) that sampled based on infertility treatment and plurality. Included in the study were infants born between 2008 and 2010 in New York state (excluding New York City) whose parents completed developmental screening instruments through 36 months of age. A total of 4824 mothers (97% of 4989) completed 1 or more developmental screening instruments for 5841 children, including 1830 conceived with infertility treatment and 2074 twins.

EXPOSURES

Maternal self-report of any infertility treatment was further categorized into ART and ovulation induction/intrauterine insemination. Assisted reproductive technology use was previously validated by linkage with the Society for Assisted Reproductive Technology-Clinical Outcome Reporting System.

MAIN OUTCOMES AND MEASURES

Five developmental domains (fine motor, gross motor, communication, personal-social functioning, and problem-solving ability), as measured by the parental completion of the Ages and Stages Questionnaires at 4, 8, 12, 18, 24, 30, and 36 months of age. Generalized linear mixed modeling techniques estimated adjusted odds ratios (aORs) and 95% CIs for use and type of infertility treatment in relation to failing a developmental domain. Data were stratified by plurality and weighted for the sampling scheme.

RESULTS

There were 1422 mothers (29.5%; mean [SD], age, 34.1 [5.2] years) who underwent infertility treatment. Infertility treatment was not associated with risk of their children failing any developmental domain (aOR, 1.33; 95% CI, 0.94-1.89). Assisted reproductive technology was associated with increased risk for failing any developmental domain but only when singletons and twins were evaluated together (aOR, 1.81; 95% CI, 1.21-2.72). Adjustment for birth weight further attenuated this estimate (aOR, 1.26; 95% CI, 0.82-1.93). After stratifying by plurality, type of treatment also was not significantly associated with failing any developmental domain for ovulation induction/intrauterine insemination (aOR, 1.00; 95% CI, 0.57-1.77 for singletons and aOR, 1.30; 95% CI, 0.76-2.21 for twins) or ART (aOR, 1.38; 95% CI, 0.78-2.43 for singletons and aOR, 1.58; 95% CI, 0.94-2.65 for twins).

CONCLUSIONS AND RELEVANCE

After considering plurality, children's development through age 3 years was similar irrespective of infertility treatment or specific type. To our knowledge, these findings are among the first to focus on non-ART treatments in the United States.