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

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.

Maternal oxytocin treatment at birth increases epigenetic age in male offspring

Exogenous oxytocin (OT) is widely used to induce or augment labor with little understanding of the impact on offspring development. In rodent models, including the prairie vole (Microtus ochrogaster), it has been shown that oxytocin administered to mothers can affect the nervous system of the offspring with long lasting behavioral effects especially on sociality. Here, we examined the hypothesis that perinatal oxytocin exposure could have epigenetic and transcriptomic consequences. Prairie voles were exposed to exogenous oxytocin, through injections given to the mother just prior to birth, and were studied at the time of weaning. The outcome of this study revealed increased epigenetic age in oxytocin-exposed animals compared to the saline-exposed group. Oxytocin exposure led to 900 differentially methylated CpG sites (annotated to 589 genes), and 2 CpG sites (2 genes) remained significantly different after correction for multiple comparisons. Differentially methylated CpG sites were enriched in genes known to be involved in regulation of gene expression and neurodevelopment. Using RNA-sequencing we also found 217 nominally differentially expressed genes (p<0.05) in nucleus accumbens, a brain region involved in reward circuitry and social behavior; after corrections for multiple comparisons 6 genes remained significantly differentially expressed. Finally, we found that maternal oxytocin administration led to widespread alternative splicing in the nucleus accumbens. These results indicate that oxytocin exposure during birth may have long lasting epigenetic consequences. A need for further investigation of how oxytocin administration impacts development and behavior throughout the lifespan is supported by these outcomes.

A nationwide, prospective, cohort study on exogenous oxytocin and delays in early child development: the Japan environment and children's study

Although it remains debatable, exogenous oxytocin, commonly used for labour induction and augmentation, reportedly increases risks of neurodevelopment delay, attention-deficit/hyperactivity disorder, and autism spectrum disorder among children prenatally exposed to exogenous oxytocin. However, only few studies have objectively examined exogenous oxytocin's impact on early childhood development through scoring evaluations. This study investigated the association between exogenous oxytocin exposure and neurodevelopment in 3-year-old children using the Ages and Stages Questionnaires, Third Edition. In this nationwide prospective cohort study, we extracted data from 104,062 foetal records regarding exogenous oxytocin use during labour from the Japan Environment and Children's Study. Participants completed questionnaires throughout the pregnancy and postpartum periods. Outcomes comprised the developmental status less than each cut-off value for the five domains of the Ages and Stages Questionnaire, Third Edition. We conducted multivariable logistic regression analyses on the data of 55,400 children after controlling for confounders. Among the 55,400 included women, 19.0% (n = 10,506) used exogenous oxytocin during labour and 81.0% (n = 44,894) did not. Children exposed to exogenous oxytocin showed no significantly increased risk of developmental delay in any domain (communication: odds ratio [OR] 1.04, 95% confidence interval [CI] 0.92-1.16; gross motor: OR 0.97, 95% CI 0.87-1.08; fine motor: OR 1.00, 95% CI 0.92-1.09; problem-solving: OR 1.02, 95% CI 0.94-1.11; personal-social: OR 0.91, 95% CI 0.80-1.03).   Conclusion: Exogenous oxytocin for labour induction did not adversely affect early childhood development. Further studies accounting for the degree of exogenous oxytocin exposure are required to confirm these results. What is Known: • In developed countries, labour is induced in 20-25% of all pregnancies, for which oxytocin is commonly used. • Studies have associated risks of neurodevelopment delay, attention-deficit/hyperactivity disorder, and autism spectrum disorder with exposure to exogenous oxytocin. What is New: • Evaluation with the Ages and Stages Questionnaire, Third Edition, revealed that exogenous oxytocin use did not adversely affect early childhood development. • This prospective study reinforced the lack of evidence of an association between exogenous oxytocin use and early childhood development after adjustment for confounding and rigorous bias elimination.

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.

Neuroanatomical and functional consequences of oxytocin treatment at birth in prairie voles

Birth is a critical period for the developing brain, a time when surging hormone levels help prepare the fetal brain for the tremendous physiological changes it must accomplish upon entry into the 'extrauterine world'. A number of obstetrical conditions warrant manipulations of these hormones at the time of birth, but we know little of their possible consequences on the developing brain. One of the most notable birth signaling hormones is oxytocin, which is administered to roughly 50% of laboring women in the United States prior to / during delivery. Previously, we found evidence for behavioral, epigenetic, and neuroendocrine consequences in adult prairie vole offspring following maternal oxytocin treatment immediately prior to birth. Here, we examined the neurodevelopmental consequences in adult prairie vole offspring following maternal oxytocin treatment prior to birth. Control prairie voles and those exposed to 0.25 mg/kg oxytocin were scanned as adults using anatomical and functional MRI, with neuroanatomy and brain function analyzed as voxel-based morphometry and resting state functional connectivity, respectively. Overall, anatomical differences brought on by oxytocin treatment, while widespread, were generally small, while differences in functional connectivity, particularly among oxytocin-exposed males, were larger. Analyses of functional connectivity based in graph theory revealed that oxytocin-exposed males in particular showed markedly increased connectivity throughout the brain and across several parameters, including closeness and degree. These results are interpreted in the context of the organizational effects of oxytocin exposure in early life and these findings add to a growing literature on how the perinatal brain is sensitive to hormonal manipulations at birth.

Maternal and newborn plasma oxytocin levels in response to maternal synthetic oxytocin administration during labour, birth and postpartum - a systematic review with implications for the function of the oxytocinergic system

BACKGROUND

The reproductive hormone oxytocin facilitates labour, birth and postpartum adaptations for women and newborns. Synthetic oxytocin is commonly given to induce or augment labour and to decrease postpartum bleeding.

AIM

To systematically review studies measuring plasma oxytocin levels in women and newborns following maternal administration of synthetic oxytocin during labour, birth and/or postpartum and to consider possible impacts on endogenous oxytocin and related systems.

METHODS

Systematic searches of PubMed, CINAHL, PsycInfo and Scopus databases followed PRISMA guidelines, including all peer-reviewed studies in languages understood by the authors. Thirty-five publications met inclusion criteria, including 1373 women and 148 newborns. Studies varied substantially in design and methodology, so classical meta-analysis was not possible. Therefore, results were categorized, analysed and summarised in text and tables.

RESULTS

Infusions of synthetic oxytocin increased maternal plasma oxytocin levels dose-dependently; doubling the infusion rate approximately doubled oxytocin levels. Infusions below 10 milliunits per minute (mU/min) did not raise maternal oxytocin above the range observed in physiological labour. At high intrapartum infusion rates (up to 32 mU/min) maternal plasma oxytocin reached 2-3 times physiological levels. Postpartum synthetic oxytocin regimens used comparatively higher doses with shorter duration compared to labour, giving greater but transient maternal oxytocin elevations. Total postpartum dose was comparable to total intrapartum dose following vaginal birth, but post-caesarean dosages were higher. Newborn oxytocin levels were higher in the umbilical artery vs. umbilical vein, and both were higher than maternal plasma levels, implying substantial fetal oxytocin production in labour. Newborn oxytocin levels were not further elevated following maternal intrapartum synthetic oxytocin, suggesting that synthetic oxytocin at clinical doses does not cross from mother to fetus.

CONCLUSIONS

Synthetic oxytocin infusion during labour increased maternal plasma oxytocin levels 2-3-fold at the highest doses and was not associated with neonatal plasma oxytocin elevations. Therefore, direct effects from synthetic oxytocin transfer to maternal brain or fetus are unlikely. However, infusions of synthetic oxytocin in labour change uterine contraction patterns. This may influence uterine blood flow and maternal autonomic nervous system activity, potentially harming the fetus and increasing maternal pain and stress.

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.

Peripartum effects of synthetic oxytocin: The good, the bad, and the unknown

The first clinical applications of oxytocin (OT) were in obstetrics as a hormone to start and speed up labor and to control postpartum hemorrhage. Discoveries in the 1960s and 1970s revealed that the effects of OT are not limited to its peripheral actions around birth and milk ejection. Indeed, OT also acts as a neuromodulator in the brain affecting fear memory, social attachment, and other forms of social behaviors. The peripheral and central effects of OT have been separately subject to extensive scrutiny. However, the effects of peripheral OT-particularly in the form of administration of synthetic OT (synOT) around birth-on the central nervous system are surprisingly understudied. Here, we provide a narrative review of the current evidence, suggest putative mechanisms of synOT action, and provide new directions and hypotheses for future studies to bridge the gaps between neuroscience, obstetrics, and psychiatry.

Effects of different doses of synthetic oxytocin on neonatal instinctive behaviors and breastfeeding

Synthetic oxytocin is the current domestic first-line agent of induced labor and labor augmentation, and its potential effects on neonatal neurobehavioral development is currently attracting increased attention. To explore the effect of different doses of synthetic oxytocin on neonatal instinctive breastfeeding behavior and breastfeeding by observing neonatal behaviors during skin-to-skin contact with mothers after delivery. Observations and comparisons of neonatal instinctive behaviors were conducted by using Widström's 9 Stages method. According to the total dosage of oxytocin administered during labor, participants were divided into a low dose group (≤ 2.5 U) of 39 pairs, a medium dose group (> 2.5 U) of 38 pairs, a high dose group (> 7.5 U) of 38 pairs and a control group (no synthetic oxytocin use) of 39 pairs. The occurrence time of newborns' instinctive movements and the duration of each behavior stage for the four groups were also analyzed. The number of exclusive breastfeeding sessions within 3 days after birth and the rate of exclusive breastfeeding at 3 months were collected and compared. There were significant differences among the four groups in the occurrence time of raising head or turning head (p = 0.004), eating hands (p = 0.011), moving body (p = 0.001), locating areola (p < 0.001), licking nipples (p = 0.002), containing nipple (p = 0.001), sucking (p < 0.001). There were significant differences among the four groups in the duration of activity (p = 0.004), clawing (p = 0.001), familiarization (p = 0.001), and sucking (p < 0.001). There was also a significant difference in the number of exclusive breastfeeding sessions of 24 h (p = 0.011), 48 h (p < 0.001), 72 h (p = 0.001) after birth among the four groups, but there was no statistical difference in the rate of exclusive breastfeeding at 3 months after birth. The intrapartum administration of synthetic oxytocin was associated with the expression of neonatal instinctive breastfeeding. With increases in drug dose, the effect of breast seeking activity and breast attachment was more significant, and the association of synthetic oxytocin on sucking and breastfeeding was dose-dependent.

Birth with synthetic oxytocin and the risk of being overweight or obese during childhood

BACKGROUND

Despite the importance of oxytocinergic signalling for satiety regulation and energy balance, the impact of exposure to synthetic oxytocin during childbirth on obesity during childhood remains unknown.

OBJECTIVES

To examine the association between oxytocin exposure during labour and the risk of being overweight or obese during childhood.

METHODS

Synthetic oxytocin exposure data of mothers from the Danish Medical Birth Registry were linked with self-reported anthropometric data of their children from the Danish National Birth Cohort (5 months-11 years of age). Multinomial logistic regression and latent class growth analyses were performed to determine the association between oxytocin exposure and obesity during childhood.

RESULTS

With the exception of the normal weight-to-overweight group between ages 5 and 12 months, none of the other analyses revealed a significant association between synthetic oxytocin use and the risk of being overweight until the age of 11 years. Furthermore, latent class growth analysis did not reveal an association between oxytocin exposure at birth and the risk of being overweight or obese during childhood.

CONCLUSIONS

Our analysis of a large cohort of children who varied in their synthetic oxytocin exposure status at childbirth did not reveal an association between oxytocin exposure and the risk of childhood overweight/obesity.

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.

Prenatal Progestin Exposure-Mediated Oxytocin Suppression Contributes to Social Deficits in Mouse Offspring

Epidemiological studies have shown that maternal hormone exposure is associated with autism spectrum disorders (ASD). The hormone oxytocin (OXT) is a central nervous neuropeptide that plays an important role in social behaviors as well as ASD etiology, although the detailed mechanism remains largely unknown. In this study, we aim to investigate the potential role and contribution of OXT to prenatal progestin exposure-mediated mouse offspring. Our in vitro study in the hypothalamic neurons that isolated from paraventricular nuclei area of mice showed that transient progestin exposure causes persistent epigenetic changes on the OXT promoter, resulting in dissociation of estrogen receptor β (ERβ) and retinoic acid-related orphan receptor α (RORA) from the OXT promoter with subsequent persistent OXT suppression. Our in vivo study showed that prenatal exposure of medroxyprogesterone acetate (MPA) triggers social deficits in mouse offspring; prenatal OXT deficiency in OXT knockdown mouse partly mimics, while postnatal ERβ expression or postnatal OXT peptide injection partly ameliorates, prenatal MPA exposure-mediated social deficits, which include impaired social interaction and social abilities. On the other hand, OXT had no effect on prenatal MPA exposure-mediated anxiety-like behaviors. We conclude that prenatal MPA exposure-mediated oxytocin suppression contributes to social deficits in mouse offspring.

Oxytocin administration for induction and augmentation of labour in polish maternity units - an observational study

BACKGROUND

There is not enough data regarding practices and protocols on the dose of oxytocin administrated to women during labour. Empirical evidence indicates that compliance with the guidelines improves the quality of healthcare and reduces adverse effects. The study aimed to evaluate practices of oxytocin provision for labour induction and augmentation in two maternity units in Poland.

METHODS

The article presents a prospective observational study. Data from 545 (n = 545) labours was collected in two maternity units. First, the total dose (the total amount of oxytocin provided from the beginning in the labour ward until delivery including the III and IV stage of labour) and cumulative dose of oxytocin (the amount of oxytocin given until the birth of the neonate) administered to women during labour was calculated. Then, the relationship between the cumulative dose of oxytocin and short term perinatal outcomes (mode of delivery, use of epidural anaesthesia, Apgar scores, birth weight and postpartum blood loss) was analysed. Finally, the compliance of oxytocin supply during labour with national guidelines in the following five criteria: medium, start dose, escalation rate, interval, the continuation of infusion after established labour was examined.

RESULTS

The average cumulative dose of oxytocin administrated to women before birth was 4402 mU following labour induction and 2366 mU following labour augmentation. The actual administration of oxytocin deviated both from the unit and national guidelines in 93.6% of all observed labours (mainly because of continuation of infusion after established labour). We found no statistically significant correlation between the cumulative dose of oxytocin administered and mode of delivery, immediate postpartum blood loss or Apgar scores. There was no observed effect of cumulative dose oxytocin on short-term perinatal outcomes. The two units participating in the study had similar protocols and did not differ significantly in terms of total oxytocin dose, rates of induction and augmentation - the only observed difference was the mode of delivery.

CONCLUSIONS

The study showed no effect of the mean cumulative oxytocin dose on short-term perinatal outcomes and high rate of non-compliance of the practice of oxytocin administration for labour induction and augmentation with the national recommendations. Cooperation between different professional groups of maternity care providers should be considered in building national guidelines for maternity care.. Further studies investigating possible long-term effects of the meant cumulative dose of oxytocin and the reasons for non-compliance of practice with guidelines should be carried out.

The oxytocin system and early-life experience-dependent plastic changes

Early-life experience influences social and emotional behaviour in adulthood. Affiliative tactile stimuli in early life facilitate the development of social and emotional behaviour, whereas early-life adverse stimuli have been shown to increase the risk of various diseases in later life. On the other hand, oxytocin has been shown to have organizational actions during early-life stages. However, the detailed mechanisms of the effects of early-life experience and oxytocin remain unclear. Here, we review the effects of affiliative tactile stimuli during the neonatal period and neonatal oxytocin treatment on the activity of the oxytocin-oxytocin receptor system and social or emotional behaviour in adulthood. Both affiliative tactile stimuli and early-life adverse stimuli in the neonatal period acutely activate the oxytocin-oxytocin receptor system in the brain but modulate social behaviour and anxiety-related behaviour apparently in an opposite direction in adulthood. Accumulating evidence suggests that affiliative tactile stimuli and exogenous application of oxytocin in early-life stages induce higher activity of the oxytocin-oxytocin receptor system in adulthood, although the effects are dependent on experimental procedures, sex, dosages and brain regions examined. On the other hand, early-life stressful stimuli appear to induce reduced activity of the oxytocin-oxytocin receptor system, possibly leading to adverse actions in adulthood. It is possible that activation of a specific oxytocin system can induce beneficial actions against early-life maltreatments and thus could be used for the treatment of developmental psychiatric disorders.

Oxytocin: at birth and beyond. A systematic review of the long-term effects of peripartum oxytocin

Oxytocin is one of the most commonly used medications during labour and delivery. Recent insights from basic neuroscience research suggest that the uterotonic effects of oxytocin may arguably be trivial when compared with its profound effects on higher-order human behaviour. The purpose of this review is to highlight the potential consequences of manipulating oxytocinergic signalling during the peripartum period and its long-term impact on the maternal-infant dyad. We identified four domains where modulation of oxytocinergic signalling might be consequential: postpartum depression; breastfeeding; neurodevelopment; and chronic pain, and performed a literature search to address the impact of peripartum oxytocin administration. We have shown modest, but inconsistent, evidence linking peripartum oxytocin administration with postpartum depression. Breastfeeding success appeared to be negatively correlated with peripartum oxytocin exposure, perhaps secondary to impaired primitive neonatal reflexes and maternal-infant bonding. The association between perinatal oxytocin exposure and subsequent development of neurodevelopmental disorders such as autism in the offspring was weak, but these studies were limited by the lack of information on the cumulative dose. Finally, we identified substantial evidence for analgesic and anti-hypersensitivity effects of oxytocin which might partly explain the low incidence of chronic pain after caesarean birth. Although most data presented here are observational, our review points to a compelling need for robust clinical studies to better dissect the impact of peripartum oxytocin administration, and as stewards of its use, increase the precision with which we administer oxytocin to prevent overuse of the drug.

H2S and Oxytocin Systems in Early Life Stress and Cardiovascular Disease

Today it is well established that early life stress leads to cardiovascular programming that manifests in cardiovascular disease, but the mechanisms by which this occurs, are not fully understood. This perspective review examines the relevant literature that implicates the dysregulation of the gasomediator hydrogen sulfide and the neuroendocrine oxytocin systems in heart disease and their putative mechanistic role in the early life stress developmental origins of cardiovascular disease. Furthermore, interesting hints towards the mutual interaction of the hydrogen sulfide and OT systems are identified, especially with regards to the connection between the central nervous and the cardiovascular system, which support the role of the vagus nerve as a communication link between the brain and the heart in stress-mediated cardiovascular disease.

Maternal Diabetes-Induced Suppression of Oxytocin Receptor Contributes to Social Deficits in Offspring

Autism spectrum disorders (ASD) are a group of neurodevelopmental disorders characterized by impaired skills in social interaction and communication in addition to restricted and repetitive behaviors. Many different factors may contribute to ASD development; in particular, oxytocin receptor (OXTR) deficiency has been reported to be associated with ASD, although the detailed mechanism has remained largely unknown. Epidemiological study has shown that maternal diabetes is associated with ASD development. In this study, we aim to investigate the potential role of OXTR on maternal diabetes-mediated social deficits in offspring. Our in vitro study of human neuron progenitor cells showed that hyperglycemia induces OXTR suppression and that this suppression remains during subsequent normoglycemia. Further investigation showed that OXTR suppression is due to hyperglycemia-induced persistent oxidative stress and epigenetic methylation in addition to the subsequent dissociation of estrogen receptor β (ERβ) from the OXTR promoter. Furthermore, our in vivo mouse study showed that maternal diabetes induces OXTR suppression; prenatal OXTR deficiency mimics and potentiates maternal diabetes-mediated anxiety-like behaviors, while there is less of an effect on autism-like behaviors. Additionally, postnatal infusion of OXTR partly, while infusion of ERβ completely, reverses maternal diabetes-induced social deficits. We conclude that OXTR may be an important factor for ASD development and that maternal diabetes-induced suppression of oxytocin receptor contributes to social deficits in offspring.

Is Oxytocin "Nature's Medicine"?

Oxytocin is a pleiotropic, peptide hormone with broad implications for general health, adaptation, development, reproduction, and social behavior. Endogenous oxytocin and stimulation of the oxytocin receptor support patterns of growth, resilience, and healing. Oxytocin can function as a stress-coping molecule, an anti-inflammatory, and an antioxidant, with protective effects especially in the face of adversity or trauma. Oxytocin influences the autonomic nervous system and the immune system. These properties of oxytocin may help explain the benefits of positive social experiences and have drawn attention to this molecule as a possible therapeutic in a host of disorders. However, as detailed here, the unique chemical properties of oxytocin, including active disulfide bonds, and its capacity to shift chemical forms and bind to other molecules make this molecule difficult to work with and to measure. The effects of oxytocin also are context-dependent, sexually dimorphic, and altered by experience. In part, this is because many of the actions of oxytocin rely on its capacity to interact with the more ancient peptide molecule, vasopressin, and the vasopressin receptors. In addition, oxytocin receptor(s) are epigenetically tuned by experience, especially in early life. Stimulation of G-protein–coupled receptors triggers subcellular cascades allowing these neuropeptides to have multiple functions. The adaptive properties of oxytocin make this ancient molecule of special importance to human evolution as well as modern medicine and health; these same characteristics also present challenges to the use of oxytocin-like molecules as drugs that are only now being recognized.