Association of Labor Induction With Offspring Risk of Autism Spectrum Disorders

A case-control study on pre-, peri-, and neonatal risk factors associated with autism spectrum disorder among Armenian children

We aimed to investigate the role of pre-, peri- and neonatal risk factors in the development of autism spectrum disorder (ASD) among Armenian children with the goal of detecting and addressing modifiable risk factors to reduce ASD incidence. For this purpose a retrospective case-control study using a random proportional sample of Armenian children with ASD to assess associations between various factors and ASD was conducted. The study was approved by the local ethical committee, and parental written consent was obtained. A total of 168 children with ASD and 329 controls were included in the analysis. Multivariable logistic regression analysis revealed that male gender, maternal weight gain, use of MgB6, self-reported stress during the pregnancy, pregnancy with complications, as well as use of labor-inducing drugs were associated with a significant increase in the odds of ASD, whereas Duphaston use during pregnancy, the longer interpregnancy interval and birth height were associated with decreased odds of ASD. These findings are pertinent as many identified factors may be preventable or modifiable, underscoring the importance of timely and appropriate public health strategies aimed at disease prevention in pregnant women to reduce ASD incidence.

Intrapartum exposure to synthetic oxytocin, maternal BMI, and neurodevelopmental outcomes in children within the ECHO consortium

BACKGROUND

Synthetic oxytocin (sOT) is frequently administered during parturition. Studies have raised concerns that fetal exposure to sOT may be associated with altered brain development and risk of neurodevelopmental disorders. In a large and diverse sample of children with data about intrapartum sOT exposure and subsequent diagnoses of two prevalent neurodevelopmental disorders, i.e., attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), we tested the following hypotheses: (1) Intrapartum sOT exposure is associated with increased odds of child ADHD or ASD; (2) associations differ across sex; (3) associations between intrapartum sOT exposure and ADHD or ASD are accentuated in offspring of mothers with pre-pregnancy obesity.

METHODS

The study sample comprised 12,503 participants from 44 cohort sites included in the Environmental Influences on Child Health Outcomes (ECHO) consortium. Mixed-effects logistic regression analyses were used to estimate the association between intrapartum sOT exposure and offspring ADHD or ASD (in separate models). Maternal obesity (pre-pregnancy BMI ≥ 30 kg/m2) and child sex were evaluated for effect modification.

RESULTS

Intrapartum sOT exposure was present in 48% of participants. sOT exposure was not associated with increased odds of ASD (adjusted odds ratio [aOR] 0.86; 95% confidence interval [CI], 0.71-1.03) or ADHD (aOR 0.89; 95% CI, 0.76-1.04). Associations did not differ by child sex. Among mothers with pre-pregnancy obesity, sOT exposure was associated with lower odds of offspring ADHD (aOR 0.72; 95% CI, 0.55-0.96). No association was found among mothers without obesity (aOR 0.97; 95% CI, 0.80-1.18).

CONCLUSIONS

In a large, diverse sample, we found no evidence of an association between intrapartum exposure to sOT and odds of ADHD or ASD in either male or female offspring. Contrary to our hypothesis, among mothers with pre-pregnancy obesity, sOT exposure was associated with lower odds of child ADHD diagnosis.

Oxytocin-induced birth causes sex-specific behavioral and brain connectivity changes in developing rat offspring

Despite six decades of the use of exogenous oxytocin for management of labor, little is known about its effects on the developing brain. Motivated by controversial reports suggesting a link between oxytocin use during labor and autism spectrum disorders (ASDs), we employed our recently validated rat model for labor induction with oxytocin to address this important concern. Using a combination of molecular biological, behavioral, and neuroimaging assays, we show that induced birth with oxytocin leads to sex-specific disruption of oxytocinergic signaling in the developing brain, decreased communicative ability of pups, reduced empathy-like behaviors especially in male offspring, and widespread sex-dependent changes in functional cortical connectivity. Contrary to our hypothesis, social behavior, typically impaired in ASDs, was largely preserved. Collectively, our foundational studies provide nuanced insights into the neurodevelopmental impact of birth induction with oxytocin and set the stage for mechanistic investigations in animal models and prospective longitudinal clinical studies.

Identifying Novel Drug Targets for Epilepsy Through a Brain Transcriptome-Wide Association Study and Protein-Wide Association Study with Chemical-Gene-Interaction Analysis

Epilepsy is a severe neurological condition affecting 50-65 million individuals worldwide that can lead to brain damage. Nevertheless, the etiology of epilepsy remains poorly understood. Meta-analyses of genome-wide association studies involving 15,212 epilepsy cases and 29,677 controls of the ILAE Consortium cohort were used to conduct transcriptome-wide association studies (TWAS) and protein-wide association studies (PWAS). Furthermore, a protein-protein interaction (PPI) network was generated using the STRING database, and significant epilepsy-susceptible genes were verified using chip data. Chemical-related gene set enrichment analysis (CGSEA) was performed to determine novel drug targets for epilepsy. TWAS analysis identified 21,170 genes, of which 58 were significant (TWASfdr < 0.05) in ten brain regions, and 16 differentially expressed genes were verified based on mRNA expression profiles. The PWAS identified 2249 genes, of which 2 were significant (PWASfdr < 0.05). Through chemical-gene set enrichment analysis, 287 environmental chemicals associated with epilepsy were identified. We identified five significant genes (WIPF1, IQSEC1, JAM2, ICAM3, and ZNF143) that had causal relationships with epilepsy. CGSEA identified 159 chemicals that were significantly correlated with epilepsy (Pcgsea < 0.05), such as pentobarbital, ketone bodies, and polychlorinated biphenyl. In summary, we performed TWAS, PWAS (for genetic factors), and CGSEA (for environmental factors) analyses and identified several epilepsy-associated genes and chemicals. The results of this study will contribute to our understanding of genetic and environmental factors for epilepsy and may predict novel drug targets.

Exogenous oxytocin administration during labor and autism spectrum disorder

BACKGROUND

Oxytocin is a neuropeptide hormone that plays a key role in social behavior, stress regulation, and mental health. Synthetic oxytocin administration is a common obstetrical practice, and importantly, previous research has suggested that intrapartum exposure may increase the risk of neurodevelopmental disorders, such as autism spectrum disorder.

OBJECTIVE

This study aimed to examine the association between synthetic oxytocin exposure during labor and autism spectrum disorder diagnosis in the child.

STUDY DESIGN

This population-based retrospective cohort study compared 2 cohorts of children: (1) all children born in British Columbia, Canada between April 1, 2000 and December 31, 2014 (n=414,336 births), and (2) all children delivered at Soroka University Medical Center in Be'er-Sheva, Israel between January 1, 2011 and December 31, 2019 (n=82,892 births). Nine different exposure groups were examined. Cox proportional hazards models were used to estimate crude and adjusted hazard ratios of autism spectrum disorder in both cohorts on the basis of induction and/or augmentation exposure status. To further control for confounding by indication, we conducted sensitivity analyses among a cohort of healthy, uncomplicated deliveries and among a group that was induced only for postdates. In addition, we stratified our analyses by infant sex to assess for potential sex differences.

RESULTS

In the British Columbia cohort, 170,013 of 414,336 deliveries (41.0%) were not induced or augmented, 107,543 (26.0%) were exposed to oxytocin, and 136,780 (33.0%) were induced or augmented but not exposed to oxytocin. In the Israel cohort, 51,790 of 82,892 deliveries (62.5%) were not induced or augmented, 28,852 (34.8%) were exposed to oxytocin, and 2250 (2.7%) were induced or augmented but not exposed to oxytocin. On adjusting for covariates in the main analysis, significant associations were observed in the Israel cohort, including adjusted hazard ratios of 1.51 (95% confidence interval, 1.20-1.90) for oxytocin-augmented births and 2.18 (95% confidence interval, 1.32-3.57) for those induced by means other than oxytocin and not augmented. However, oxytocin induction was not significantly associated with autism spectrum disorder in the Israel cohort. In the Canadian cohort, there were no statistically significant adjusted hazard ratios. Further, no significant sex differences were observed in the fully adjusted models.

CONCLUSION

This study supports that induction of labor through oxytocin administration does not increase the risk of autism spectrum disorder in the child. Our international comparison of 2 countries with differences in clinical practice regarding oxytocin administration for induction and/or augmentation suggests that previous studies reporting a significant association were likely confounded by the underlying indication for the induction.

Exploring potential impacts of pregnancy-related maternal immune activation and extracellular vesicles on immune alterations observed in autism spectrum disorder

Autism Spectrum Disorder (ASD) is a set of neurodevelopmental disorders usually observed in early life, with impacts on behavioral and social skills. Incidence of ASD has been dramatically increasing worldwide, possibly due to increase in awareness/diagnosis as well as to genetic and environmental triggers. Currently, it is estimated that ∼1% of the world population presents ASD symptoms. In addition to its genetic background, environmental and immune-related factors also influence the ASD etiology. In this context, maternal immune activation (MIA) has recently been suggested as a component potentially involved in ASD development. In addition, extracellular vesicles (EVs) are abundant at the maternal-fetal interface and are actively involved in the immunoregulation required for a healthy pregnancy. Considering that alterations in concentration and content of EVs have also been associated with ASD, this article raises a debate about the potential roles of EVs in the processes surrounding MIA. This represents the major differential of the present review compared to other ASD studies. To support the suggested correlations and hypotheses, findings regarding the roles of EVs during pregnancy and potential influences on ASD are discussed, along with a review and update concerning the participation of infections, cytokine unbalances, overweight and obesity, maternal anti-fetal brain antibodies, maternal fever, gestational diabetes, preeclampsia, labor type and microbiota unbalances in MIA and ASD.

Labor epidural analgesia and subsequent risk of offspring autism spectrum disorder and attention-deficit/hyperactivity disorder: a cross-national cohort study of 4.5 million individuals and their siblings

BACKGROUND

A recent study has suggested that labor epidural analgesia may be associated with increased rates of offspring autism spectrum disorder. Subsequent replication attempts have lacked sufficient power to confidently exclude the possibility of a small effect, and the causal nature of this association remains unknown.

OBJECTIVE

This study aimed to investigate the extent to which exposure to labor epidural analgesia is associated with offspring autism spectrum disorder and attention-deficit/hyperactivity disorder following adjustments for unmeasured familial confounding.

STUDY DESIGN

We identified 4,498,462 singletons and their parents using the Medical Birth Registers in Finland (cohorts born from 1987-2005), Norway (1999-2015), and Sweden (1987-2011) linked with population and patient registries. These cohorts were followed from birth until they either had the outcomes of interest, emigrated, died, or reached the end of the follow-up (at mean ages 13.6-16.8 years), whichever occurred first. Cox regression models were used to estimate country-specific associations between labor epidural analgesia recorded at birth and outcomes (eg, at least 1 secondary care diagnosis of autism spectrum disorder and attention-deficit/hyperactivity disorder or at least 1 dispensed prescription of medication used for the treatment of attention-deficit/hyperactivity disorder). The models were adjusted for sex, birth year, birth order, and unmeasured familial confounders via sibling comparisons. Pooled estimates across all the 3 countries were estimated using inverse variance weighted fixed-effects meta-analysis models.

RESULTS

A total of 4,498,462 individuals (48.7% female) were included, 1,091,846 (24.3%) of which were exposed to labor epidural analgesia. Of these, 1.2% were diagnosed with autism spectrum disorder and 4.0% with attention-deficit/hyperactivity disorder. On the population level, pooled estimates showed that labor epidural analgesia was associated with increased risk of offspring autism spectrum disorder (adjusted hazard ratio, 1.12; 95% confidence interval, 1.10-1.14, absolute risks, 1.20% vs 1.07%) and attention-deficit/hyperactivity disorder (adjusted hazard ratio, 1.20; 95% confidence interval, 1.19-1.21; absolute risks, 3.95% vs 3.32%). However, when comparing full siblings who were differentially exposed to labor epidural analgesia, the associations were fully attenuated for both conditions with narrow confidence intervals (adjusted hazard ratio [autism spectrum disorder], 0.98; 95% confidence interval, 0.93-1.03; adjusted hazard ratio attention-deficit/hyperactivity disorder, 0.99; 95% confidence interval, 0.96-1.02).

CONCLUSION

In this large cross-national study, we found no support for the hypothesis that exposure to labor epidural analgesia causes either offspring autism spectrum disorder or attention-deficit/hyperactivity disorder.

Oxytocin Exposure in Labor and its Relationship with Cognitive Impairment and the Genetic Architecture of Autism

Whether there is a relationship between oxytocin (OXT) use in labor and the risk of autism (ASD), and the nature of such relationship, is unclear. By integrating genetic and clinical data in a sample of 176 ASD participants, we tested the hypothesis that OXT is a marker for abnormal prenatal development which leads to impairments in the process of labor. OXT-exposed ASD had more obstetric complications (P = 0.031), earlier onset of symptoms (P = 0.027), poorer cognitive development (P = 0.011), higher mutation burden across neurodevelopment genes (P = 0.020; OR = 5.33) and lower transmission of polygenic risk for ASD (P = 0.0319), than non-exposed ASD. OXT seems to constitute a risk indicator rather than a risk factor for ASD, which is relevant for diagnostic and genetic counselling.

Elective Deliveries and the Risk of Autism

INTRODUCTION

Cesarean section and induced deliveries have increased substantially in the U.S., coinciding with increases in autism spectrum disorder. Studies have documented associations between cesarean section deliveries and autism spectrum disorder but have not comprehensively accounted for medical risks. This study evaluates the extent to which cesarean section and induced deliveries are associated with autism spectrum disorder in low-risk births.

METHODS

In this retrospective cohort study, California's birth records (1992-2012) were linked to hospital discharge records to identify low-risk births using a stringent algorithm based on Joint Commission guidelines. Autism spectrum disorder status was based on California Department of Developmental Service data. Logistic regression models were used to estimate associations between autism spectrum disorder and induced vaginal deliveries, cesarean section deliveries not following induction, and cesarean section deliveries following induction, with noninduced vaginal deliveries as the reference category.

RESULTS

A total of 1,488,425 low-risk births took place in California from 1992 to 2012. The adjusted odds of autism spectrum disorder were 7% higher for induced vaginal deliveries (AOR=1.07, 95% CI=1.01, 1.14), 26% higher for cesarean section deliveries not following induction (AOR=1.26, 95% CI=1.19, 1.33), and 31% higher for cesarean section deliveries following induction (AOR=1.31, 95% CI=1.18, 1.45) than for noninduced vaginal deliveries. Lower gestational age and neonatal morbidities did not appear to be important underlying pathways. The associations were insensitive to alternative model specifications and across subpopulations. These results suggest that, in low-risk pregnancies, up to 10% of autism spectrum disorder cases are potentially preventable by avoiding cesarean section deliveries.

CONCLUSIONS

After accounting for medical risks, elective deliveries-particularly cesarean section deliveries-were associated with a substantially increased risk of autism spectrum disorder.

Labor induction with oxytocin in pregnant rats is not associated with oxidative stress in the fetal brain

Despite the widespread use of oxytocin for induction of labor, mechanistic insights into fetal/neonatal wellbeing are lacking because of the absence of an animal model that recapitulates modern obstetric practice. Here, we create and validate a hi-fidelity pregnant rat model that mirrors labor induction with oxytocin in laboring women. The model consists of an implantable preprogrammed microprocessor-controlled infusion pump that delivers a gradually escalating dose of intravenous oxytocin to induce birth at term gestation. We validated the model with molecular biological experiments on the uterine myometrium and telemetry-supported assessment of changes in intrauterine pressure. Finally, we applied this model to test the hypothesis that labor induction with oxytocin would be associated with oxidative stress in the newborn brain. Analysis of biomarkers of oxidative stress and changes in the expression of associated genes were no different between oxytocin-exposed and saline-treated pups, suggesting that oxytocin-induced labor was not associated with oxidative stress in the developing brain. Collectively, we provide a viable and realistic animal model for labor induction and augmentation with oxytocin that would enable new lines of investigation related to the impact of perinatal oxytocin exposure on the mother-infant dyad.

Birth Weight and Childhood Psychopathology in the ABCD Cohort: Association is Strongest for Attention Problems and is Moderated by Sex

Many studies have shown low birth weight is associated with psychopathology later in life, particularly attention-deficit/hyperactivity disorder (ADHD). The association is well-replicated, independent from a variety of potential familial confounds, and follows a dose-response curve (decreasing birth weight linked with increasing odds of disorder). However, the specificity of the association to attention problems is called into question by the extent of comorbidity in ADHD, and recent findings that the association is stronger for autism than ADHD. We test the relative dose-response strength of birth weight on multiple aspects of behavior to explore specificity of the effect to attention problems. We also test recent suggestions that the association between birth weight and attention problems is driven by males. Our sample consisted of 9,076 children aged 9-10 from the United States (Adolescent Brain Cognitive Development study). Outcomes included 9 problem-scales and the total problems scale from the Child Behavior Checklist (CBCL). Attention problems were the most strongly associated with birth weight after controlling for gestational age, potential familial confounds, and multiple testing, supporting the outcome-specificity of this association. Contrary to recent registry-based findings, an association between birth weight and an autism scale was not observed. Sex moderated the effect of birth weight on total problems, attention problems and aggressive behavior such that these inverse associations were strongly driven by males. Our findings have strong implications for sex-specific prediction and etiological models of childhood psychopathology.

Rates of Neuropsychiatric Disorders and Gestational Age at Birth in a Danish Population

IMPORTANCE

Nonoptimal gestational durations could be associated with neurodevelopmental disabilities, yet evidence regarding finer classification of gestational age and rates of multiple major neuropsychiatric disorders beyond childhood is limited.

OBJECTIVE

To comprehensively evaluate associations between 6 gestational age groups and rates of 9 major types and 8 subtypes of childhood and adult-onset neuropsychiatric disorders.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study evaluated data from a nationwide register of singleton births in Denmark from January 1, 1978, to December 31, 2016. Data analyses were conducted from October 1, 2019, through November 15, 2020.

EXPOSURES

Gestational age subgroups were classified according to data from the Danish Medical Birth Register: very preterm (20-31 completed weeks), moderately preterm (32-33 completed weeks), late preterm (34-36 completed weeks), early term (37-38 completed weeks), term (39-40 completed weeks, reference), and late or postterm (41-45 completed weeks).

MAIN OUTCOMES AND MEASURES

Neuropsychiatric diagnostic records (International Statistical Classification of Diseases and Related Health Problems, Tenth Revision codes F00-F99) were ascertained from the Danish Psychiatric Central Register up to August 10, 2017. Poisson regression was used to estimate the incidence rate ratio (IRR) and 95% CI for neuropsychiatric disorders, adjusting for selected sociodemographic factors.

RESULTS

Of all 2 327 639 singleton births studied (1 194 925 male newborns [51.3%]), 22 647 (1.0%) were born very preterm, 19 801 (0.9%) were born moderately preterm, 99 488 (4.3%) were born late preterm, 388 416 (16.7%) were born early term, 1 198 605 (51.5%) were born at term, and 598 682 (25.7%) were born late or postterm. A gradient of decreasing IRRs was found from very preterm to late preterm for having any or each of the 9 neuropsychiatric disorders (eg, very preterm: IRR, 1.49 [95% CI, 1.43-1.55]; moderately preterm: IRR, 1.23 [95% CI, 1.18-1.28]; late preterm: IRR, 1.17 [95% CI, 1.14-1.19] for any disorders) compared with term births. Individuals born early term had 7% higher rates (IRR, 1.07 [95% CI, 1.06-1.08]) for any neuropsychiatric diagnosis and a 31% higher rate for intellectual disability (IRR, 1.31 [95% CI, 1.25-1.37]) compared with those born at term. The late or postterm group had lower IRRs for most disorders, except pervasive developmental disorders, for which the rate was higher for postterm births compared with term births (IRR, 1.06 [95% CI, 1.03-1.09]).

CONCLUSIONS AND RELEVANCE

Higher incidences of all major neuropsychiatric disorders were observed across the spectrum of preterm births. Early term and late or postterm births might not share a homogeneous low risk with individuals born at term. These findings suggest that interventions that address perinatal factors associated with nonoptimal gestation might reduce long-term neuropsychiatric risks in the population.

Acupuncture and oxytocinergic system: The promising treatment for autism

Autism spectrum disorder (ASD) is a group of heterogeneous neurodevelopmental disorders characterized by impairments activities without efficient pharmacological therapies in social interaction, speech and stereotypic patterns. Clinical studies have shown the efficacy of acupuncture as an alternative therapy for autism. The effectiveness of acupuncture as an alternative treatment for autism has been demonstrated through clinical trials. However, the molecular mechanisms that underlie these effects remain unclear. Due to its profound pro-social, anxiolytic, stress management effects, and its potential use for the treatment of psychiatric disorders associated with altered socioemotional competence, oxytocin (OT) released from the hypothalamus has attracted considerable interest. In the past decade, a number of clinical and animal studies have shown that OT administration effectively reduces core symptoms of ASD, especially social behavior deficits. Recently, the endocannabinoid system has emerged as a promising target for the treatment of autism. OT was found to facilitate the endocannabinoid-mediated social reward processes in the nucleus accumbens of the mouse brain. Furthermore, serotonin and dopamine are involved in the reward response mediated by OT. In view of these findings, we conclude that acupuncture may produce therapeutic effects on autism by triggering the hypothalamic oxytocin system, which in turn activates the release of neurotransmitters such as endocannabinoids, dopamine and serotonin. This would be a valuable guide for further research on the mechanism of treatment of autism with acupuncture.

Birth with Synthetic Oxytocin and Risk of Childhood Emotional Disorders: A Danish Population-based Study

BACKGROUND

Concerns have been raised that synthetic oxytocin, a widely used obstetric tool for labor induction and augmentation, may have deleterious effects on the neuropsychological development of children. Few studies have examined the relationship between oxytocin-stimulated labor and emotional disorders.

METHODS

We conducted a nationwide register-based cohort study including 677,629 singletons born in Denmark in the years 2000 to 2012 and followed through 2016 (median age = 10.6 years). Data on oxytocin-stimulation were obtained from the Danish Medical Birth Register. Cases of emotional disorders - anxiety, obsessive-compulsive disorder, mood or traumatic stress disorders or a redeemed prescription for a selective serotonin reuptake inhibitor - were identified using Danish patient and prescription registries.

RESULTS

Oxytocin was used to stimulate 31% of births, and oxytocin-stimulated labor was not associated with childhood emotional disorders (HR = 1.05, 95% CI 0.99, 1.11) after adjustment for maternal history of psychopathology, antidepressants during pregnancy, cohabitation status, highest educational attainment, smoking status during pregnancy, birth year, and indications for labor stimulation. The crude cox model was also small and close to unity (HR = 1.09, 95% CI 1.03, 1.15).

LIMITATIONS

About 50% of our population had reached the age of 10 years, but the outcome included disorders with later average debut ages. Oxytocin dosage levels are not recorded in the registers.

CONCLUSIONS

Our small effect size estimates suggest that perinatal synthetic oxytocin does not contribute to the development of emotional disorders. Current evidence does not warrant revision of guidelines for the use of oxytocin in obstetrics.

Early environmental risk factors for neurodevelopmental disorders - a systematic review of twin and sibling studies

While neurodevelopmental disorders (NDDs) are highly heritable, several environmental risk factors have also been suggested. However, the role of familial confounding is unclear. To shed more light on this, we reviewed the evidence from twin and sibling studies. A systematic review was performed on case control and cohort studies including a twin or sibling within-pair comparison of neurodevelopmental outcomes, with environmental exposures until the sixth birthday. From 7,315 screened abstracts, 140 eligible articles were identified. After adjustment for familial confounding advanced paternal age, low birth weight, birth defects, and perinatal hypoxia and respiratory stress were associated with autism spectrum disorder (ASD), and low birth weight, gestational age and family income were associated with attention-deficit/hyperactivity disorder (ADHD), categorically and dimensionally. Several previously suspected factors, including pregnancy-related factors, were deemed due to familial confounding. Most studies were conducted in North America and Scandinavia, pointing to a global research bias. Moreover, most studies focused on ASD and ADHD. This genetically informed review showed evidence for a range of environmental factors of potential casual significance in NDDs, but also points to a critical need of more genetically informed studies of good quality in the quest of the environmental causes of NDDs.

Obstetric oxytocin exposure and ADHD and ASD among Danish and Finnish children

Background

Some studies have indicated an increased risk of attention deficit hyperactivity disorder (ADHD) and a small, sex-specific association with autism spectrum disorder (ASD) among children prenatally exposed to obstetric oxytocin. Since oxytocin is widely used in the obstetric ward, these potentially deleterious effects are of concern. Thus, we aimed to examine whether obstetric oxytocin treatment for labour induction or augmentation is associated with ADHD and ASD in offspring born in a two-country design based on data from Denmark and Finland.

Methods

This population-based study used data from national registers in Denmark and Finland. Singletons born in Denmark 2000–10 (n = 577 380) and Finland 1991–2010 (n = 945 543), who survived infancy, were followed until 31 December 2015. ADHD and ASD were defined using diagnostic codes. For ADHD, we also included information on prescribed and redeemed ADHD medication in the definition. Hazards ratios (HRs) with 95% confidence intervals (CI), modelled with age as the underlying time scale, were calculated to estimate the associations.

Results

Oxytocin was used in 31% and 46% of the included deliveries in Denmark and Finland, respectively. In crude analyses, prenatal oxytocin was associated with an approximately 20% increased risk of ADHD and ASD, but confounder adjustment attenuated the association. The adjusted HR was 1.03, 95% CI 1.01–1.05, for ADHD and 1.05, 95% CI 1.02–1.08, for ASD. The results were similar in across country and gender.

Conclusions

We found an association between synthetic oxytocin and ADHD or ASD which is unlikely to reflect a causal association and thus should not support the concern of clinical use. Our results help to allay concerns of obstetric use of oxytocin causing ADHD or ASD.

An association of intrapartum synthetic oxytocin dosing and the odds of developing autism

A case-control study was performed to determine whether an association exists between exposure to synthetic oxytocin and a subsequent autism spectrum disorder diagnosis; 171 children under age 18 meeting Diagnostic and Statistical Manual of Mental Disorders (5th ed.) autism spectrum disorder criteria were compared to 171 children without autism spectrum disorder diagnosis matched by gender, birth year, gestational age, and maternal age at birth. A conditional logistic regression model was used to examine the association of clinical variables and autism spectrum disorder. Significantly elevated odds ratios for autism spectrum disorder were associated with first-time Cesarean section (odds ratio = 2.56), but not a repeat Cesarean section. Odds ratios were also significantly elevated for subjects whose mother’s body mass index was 35 or higher at birth (odds ratio = 2.34) and subjects in which the reason for delivery was categorized as “fetal indication” (odds ratio = 2.00). When controlling for these and other variables, the odds of developing autism spectrum disorder were significantly elevated in males with long duration of exposure (odds ratio = 3.48) and high cumulative dose of synthetic oxytocin (odds ratio = 2.79). No significant associations of synthetic oxytocin dosing and autism spectrum disorder were noted in female subjects. The association of elevated autism spectrum disorder odds found with high duration and high cumulative dose synthetic oxytocin in male subjects suggests the need for further investigation to fully elucidate any cause and effect relationship.

Mathematical Models for Possible Roles of Oxytocin and Oxytocin Receptors in Autism

This paper develops mathematical models examining possible roles of oxytocin and oxytocin receptors in the development of autism. This is done by demonstrating that mathematical operations on normalized data from the Stanford study, which establishes a correspondence between severity of autism in children and their oxytocin blood levels, generate a graph that is the same as the graph of mathematical operations on a normalized theoretical model for the severity of autism. This procedure establishes the validity of the theoretical model and the significance of oxytocin receptors in autism. A steady-state model follows, explaining the constant baseline concentrations of oxytocin observed in the cerebral spinal fluid and blood in terms of the neuromodulation by oxytocin of oxytocin receptors on the magnocellular neurons that produce oxytocin in nuclei in the hypothalamus. The implications of these models for possible roles of oxytocin and oxytocin receptors in autism are considered for several unrelated conditions that may be associated with autism. These are oxytocin receptor desensitization and downregulation as factors during labor in offspring autism development; reductions in the oxytocin receptor numbers in the fixed oxytocin receptor expression that occurs before birth; MAST Immune System disease; and the excess number of dendritic spines from lack of pruning observed in brains of autistic people. Research into the feasibility of generating magnocellular neurons and other neurons from adult stem cells is suggested as a way of doing in vitro studies of oxytocin and oxytocin receptors to assess the validity of theories presented in this paper.

Identification of Pediatric Autism Spectrum Disorder Cases Using Health Administrative Data

Administrative data are frequently used to identify Autism Spectrum Disorder (ASD) cases in epidemiological studies. However, validation studies on this mode of case ascertainment have lacked access to high-quality clinical diagnostic data and have not followed published reporting guidelines. We report on the diagnostic accuracy of using readily available health administrative data for pediatric ASD case ascertainment. The validation cohort included almost all the ASD-positive children born in British Columbia, Canada from April 1, 2000 to December 31, 2009 and consisted of 8,670 children in total. 4,079 ASD-positive and 2,787 ASD-negative children were identified using Autism Diagnostic Observation Schedule (ADOS) and Autism Diagnostic Interview-Revised (ADI-R) assessments done through the British Columbia Autism Assessment Network (BCAAN). An additional 1,804 ADOS/ADI-R assessed ASD-positive children were identified using Ministry of Education records. This prospectively collected clinical data (the diagnostic gold standard) was then linked to each child's physician billing and hospital discharge data. The diagnostic accuracy of 11 algorithms that used the administrative data to assign ASD case status was assessed. For all algorithms, high positive predictive values (PPVs) were observed alongside low values for other measures of diagnostic accuracy illustrating that PPVs alone are not an adequate measure of diagnostic accuracy. We show that British Columbia's health administrative data cannot reliably be used to discriminate between children with ASD and children with other developmental disorders. Utilizing these data may result in misclassification bias. Methodologically sound, region-specific validation studies are needed to support the use of administrative data for ASD case ascertainment. Autism Res 2020, 13: 456-463. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: Health administrative data are frequently used to identify Autism Spectrum Disorder (ASD) cases for research purposes. However, previous validation studies on this sort of case identification have lacked access to high-quality clinical diagnostic data and have not followed published reporting guidelines. We show that British Columbia's health administrative data cannot reliably be used to discriminate between children with ASD and children with other developmental disorders.

A Mathematical Model Relating Pitocin Use during Labor with Offspring Autism Development in terms of Oxytocin Receptor Desensitization in the Fetal Brain

This paper develops a mathematical model describing the potential buildup of high oxytocin concentrations in the maternal circulation during labor in terms of continuous Pitocin infusion rate, half-life, and maternal weight. Oxytocin override of the degradation of oxytocin by placental oxytocinase is introduced to model the potential transfer of oxytocin from the maternal circulation across the placenta into the fetal circulation and from there into the brain of the fetus. The desensitization unit D equal to 1.8E6 (pg·min)/ml is employed to establish a desensitization threshold and by extension, a downregulation threshold as a function of oxytocin override concentration and continuous Pitocin infusion time, that could be a factor in the subsequent development of autism among offspring. Epidemiological studies by Duke University [1], Yale University [2], and Harvard University [3] are discussed regarding Pitocin use and offspring autism development for an explanation of the weak correlations they identified. The findings of the Harvard epidemiological study are reinterpreted regarding Pitocin use and its conclusion questioned. Further evaluations of the findings of these three epidemiological studies are called for to incorporate medical information on quantity of Pitocin used, continuous Pitocin infusion rate, length of labor, and maternal weight to determine if a correlation can be established with offspring autism development above an empirically determined desensitization threshold for Pitocin use. Suggestions for research are discussed, including an alternative to continuous Pitocin infusion, pulsatile infusion of Pitocin during labor induction, which may mitigate possible offspring autism development.

Use of real-world evidence from healthcare utilization data to evaluate drug safety during pregnancy

PURPOSE

Because preapproval clinical trials typically exclude pregnant women, the evidence on drug safety during pregnancy required to inform drug labeling must come from postapproval controlled observational studies. Common designs have included pregnancy registries and case-control studies. Recently, pregnancy cohorts nested within healthcare utilization databases are increasingly being used. Despite clear advantages, these databases share some important limitations that may threaten the validity of studies emerging from them.

METHODS

This paper describes the distinctive methodological aspects of conducting drug safety studies in healthcare utilization databases with special emphasis on design and analytic approaches to minimize biases.

RESULTS

We describe considerations for study design, cohort definition, and follow-up. We then address issues related to exposure ascertainment based on prescription fills, including the importance of the etiologically relevant window and of properly accounting for preterm births. This is followed by a discussion of advantages and challenges when ascertaining maternal and infant outcomes based on secondary data. We then explore useful approaches to address confounding within the context of pregnancy research and of the potential for selection bias when restricting the cohort to live births. Finally, we consider issues related to external validity and statistical significance. The examples are mainly drawn from a pregnancy cohort nested in the Medicaid Analytic Extract.

CONCLUSIONS

The approaches presented provide guidance regarding the important methodological considerations that need to be attended to in order to generate valid, minimally biased risk when using large healthcare utilization databases for drug safety surveillance in pregnancy.

Cumulative Risk of the Oxytocin Receptor Gene Interacts with Prenatal Exposure to Oxytocin Receptor Antagonist to Predict Children's Social Communication Development

Compelling evidence for the far-reaching role of oxytocin (OT) in social cognition and affiliative behaviors set the basis for examining the association between genetic variation in the OT receptor (OXTR) gene and risk for autism spectrum disorder (ASD). In the current study, gene-environment interaction between OXTR and prenatal exposure to either OT or OXTR antagonist (OXTRA) in predicting early social communication development was examined. One hundred and fifty-three children (age: M = 4.32, SD = 1.07) were assigned to four groups based on prenatal history: children whose mothers prenatally received OXTRA and Nifedipine to delay preterm labor (n = 27); children whose mothers received Nifedipine only to delay preterm labor (n = 35); children whose mothers received OT for labor augmentation (n = 56), and a no intervention group (n = 35). Participants completed a developmental assessment of intelligence quotient (IQ), adaptive behavior, and social communication abilities. DNA was extracted via buccal swab. A genetic risk score was calculated based on four OXTR single nucleotide polymorphisms (rs53576, rs237887, rs1042778, and rs2254298) previously reported to be associated with ASD symptomatology. OXTRrisk-allele dosage was associated with more severe autism diagnostics observation schedule (ADOS) scores only in the OXTRA group. In contrast, in the Nifedipine, OT, and no intervention groups, OXTRrisk-allele dosage was not associated with children's ADOS scores. These findings highlight the importance of both genetic and environmental pathways of OT in signaling early social development and raise the need for further research in this field. Autism Res 2019, 12: 1087-1100. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: In the current study, we examined if the association between prenatal exposure to an oxytocin receptor antagonist (OXTRA) and autism spectrum disorder (ASD) related impairments are dependent on an individual's genetic background for the oxytocin receptor gene (OXTR). Children who carried a greater number of risk alleles for the OXTR gene and whose mothers received OXTRA to delay preterm labor showed more ASD-related impairments. The results highlight the importance of both genetic and environmental pathways of oxytocin in shaping early social development.

Assessing risk of neurodevelopmental disorders after birth with oxytocin: a systematic review and meta-analysis

Experts have raised concerns that oxytocin for labor induction and augmentation may have detrimental effects on the neurodevelopment of children. To investigate whether there is the reason for concern, we reviewed and evaluated the available evidence by searching databases with no language or date restrictions up to 9 September 2018. We included English-language studies reporting results on the association between perinatal oxytocin exposure and any cognitive impairment, psychiatric symptoms or disorders in childhood. We assessed the quality of studies using the Newcastle-Ottawa Quality Assessment Scales. Independent risk estimates were pooled using random-effects meta-analyses when at least two independent datasets provided data on the same symptom or disorder. Otherwise, we provided narrative summaries. Two studies examined cognitive impairment, one examined problem behavior, three examined attention-deficit/hyperactivity disorder (ADHD) and seven focused on autism spectrum disorders (ASD). We provided narrative summaries of the studies on cognitive impairment. For ADHD, the pooled risk estimate was 1.17; 95% confidence interval (CI) 0.77-1.78, based on a pooled sample size of 5 47 278 offspring. For ASD, the pooled risk estimate was 1.10; 95% CI 1.04-1.17, based on 8 87 470 offspring. Conclusions that perinatal oxytocin increases the risks of neurodevelopmental problems are premature. Observational studies of low to high quality comprise the evidence-base, and confounding, especially by the genetic or environmental vulnerability, remains an issue. Current evidence is insufficient to justify modifying obstetric guidelines for the use of oxytocin, which state that it should only be used when clinically indicated.

Moderating effect of mode of delivery on the genetics of intelligence: Explorative genome-wide analyses in ALSPAC

INTRODUCTION

Intelligence is a core construct of individual differences in cognitive abilities and a strong predictor of important life outcomes. Within recent years, rates of cesarean section have substantially increased globally, though little is known about its effect on neurodevelopmental trajectories. Thus, we aimed to investigate the influence of delivery by cesarean section on the genetics of intelligence in children.

METHODS

Participants were recruited through the Avon Longitudinal Study of Parents and Children (ALSPAC). Intelligence was measured by the Wechsler Intelligence Scale for Children (WISC). Genotyping was performed using the Illumina Human Hap 550 quad genome-wide SNP genotyping platform and was followed by imputation using MACH software. Genome-wide interaction analyses were conducted using linear regression.

RESULTS

A total of 2,421 children and 2,141,747 SNPs were subjected to the genome-wide interaction analyses. No variant reached genome-wide significance. The strongest interaction was observed at rs17800861 in the GRIN2A gene (β = -3.43, 95% CI = -4.74 to -2.12, p = 2.98E-07). This variant is predicted to be located within active chromatin compartments in the hippocampus and may influence binding of the NF-kappaB transcription factor.

CONCLUSIONS

Our results may indicate that mode of delivery might have a moderating effect on genetic disposition of intelligence in children. Studies of considerable sizes (>10,000) are likely required to more robustly detect variants governing such interaction. In summary, the presented findings prompt the need for further studies aimed at increasing our understanding of effects various modes of delivery may have on health outcomes in children.

Effects of breast stimulation for spontaneous onset of labor on salivary oxytocin levels in low-risk pregnant women: A feasibility study

Objectives

This preliminary study aimed to 1) determine changes in the salivary oxytocin (OT) level during breast stimulation for promoting the spontaneous onset of labor in low-risk term pregnancies, and 2) clarify the feasibility of the breast stimulation intervention protocol in terms of practicality and acceptability.

Methods

We used a single arm trial design. Sixteen low-risk pregnant women between 38 and 40 weeks of gestation with cephalic presentation participated. They performed breast stimulation for 3 days with an attendant midwife in a single maternity hospital. Each breast was stimulated for 15 minutes for a total of 1 hour per day. Saliva was collected 10 minutes before the intervention and 15, 30, 60, 75, and 90 minutes after the intervention, yielding 18 samples per woman.

Results

Among a total of 282 saliva samples from the 16 participants, OT level was measured in 142 samples (missing rate: 49.6%). The median OT level showed the highest values on day 3 of the breast stimulation, with a marked increase 30 min after the intervention. In the mixed models after multiple imputation for missing data, the OT level on the first day of intervention was significantly lower than that on the third day of intervention. Fatigue from breast stimulation decreased on subsequent days, and most of the women (75%) felt no discomfort with the protocol. Uterine hyperstimulation was not observed.

Conclusion

Following a 3-day breast stimulation protocol for spontaneous onset of labor, the mean OT level showed the highest values on day 3. The breast stimulation intervention protocol showed good feasibility in terms of practicality and acceptability among the pregnant women. Additional large-scale studies are warranted to confirm the protocol’s effectiveness.

Oxytocin for labour induction or augmentation as a risk factor for autism: systematic literature review

Introduction: Some studies have shown a potential association between oxytocin use during labour and autism spectrum disorder in children (ASD). We performed a systematic review of recent studies examining this association. Methods: Boolean operators (AND/OR) were used to search MEDLINE using the following search criteria: Autistic Disorder or Autism Spectrum Disorder or Autism and Labour Induction or Labour Augmentation. Articles published in English in 2013 or later were considered. Additional studies were identified by reviewing citations. Only studies conducted on people were included. Studies not accounting for potential confounding factors were excluded. Results: Four retrospective cohort studies met the inclusion criteria. One showed an association between labour induction and augmentation and ASD, one showed a weak association between labour augmentation in boys and ASD, and one showed no association between labour induction or augmentation and ASD. The largest study showed a weak association between labour induction and ASD, which was not significant when siblings were analyzed separately. Discussion and conclusions: Recently published studies do not support the hypothesis of a causal relationship between oxytocin use during labour and ASD. Benefits of medically indicated induction or augmentation of labour outweigh the theoretical risk of ASD.

A Family-Based Study of the Association Between Labor Induction and Offspring Attention-Deficit Hyperactivity Disorder and Low Academic Achievement

The current study examined associations between labor induction and both (1) offspring attention-deficit hyperactivity disorder (ADHD) diagnosis in a Swedish birth cohort born 1992-2005 (n = 1,085,008) and (2) indices of offspring low academic achievement in a sub-cohort born 1992-1997 (n = 489,196). Associations were examined in the entire sample (i.e., related and unrelated individuals) with adjustment for measured covariates and, in order to account for unmeasured confounders shared within families, within differentially exposed cousins and siblings. We observed an association between labor induction and offspring ADHD diagnosis and low academic achievement in the population. However, these associations were fully attenuated after adjusting for measured covariates and unmeasured factors that cousins and siblings share. The results suggest that observed associations between labor induction and ADHD and low academic achievement may be due to genetic and/or shared environmental factors that influence both mothers' risk of labor induction and offspring neurodevelopment.