Cognitive Outcomes of Young Children After Prenatal Exposure to Medications for Opioid Use Disorder: A Systematic Review and Meta-analysis

Impact of exposure to opioids in pregnancy on offspring developmental outcomes in the preschool years: an umbrella review

BACKGROUND

Early child development sets the course for optimal outcomes across life. Increasing numbers of children worldwide are exposed to opioids in pregnancy and frequently live in environments associated with adverse developmental outcomes. Although multiple systematic reviews have been published in this area, they use different exposures and different types of outcomes. This umbrella review aims to bring together these systematic reviews to provide a comprehensive overview of the evidence around the association between prenatal opioid exposure and preschool developmental outcomes.

METHODS

PubMed, MedLine, PsycInfo and Google Scholar were searched up to July 2024. Eligible studies were systematic reviews, meta-analyses or scoping reviews exploring prenatal opioid exposure (illicit opioids and prescribed treatments for opioid dependence) and developmental outcomes up to age 5. Reviews were screened by two authors. Quality assessment was undertaken using the Joanna Briggs Institute checklist for umbrella reviews. Degree of overlap was examined. Due to heterogeneity within the sample, no meta-analyses were undertaken and results were synthesised narratively.

RESULTS

11 reviews were included containing 478 individual papers. The overlap was slight (corrected cover area=5%). Developmental outcomes associated with prenatal opioid exposure included visual function, motor skills, externalising problems and language difficulties. No conclusive evidence was available for cognitive development or internalising symptoms. In cognitive, and motor, skills, findings differed by age, with later preschool findings being weaker. Authors frequently highlighted issues with poor quality research in the original studies, including small sample sizes and lack of controlling for confounding.

CONCLUSIONS

Multiple areas of child development were associated with prenatal opioid exposure; however, evidence was weak. Robust research, with larger sample sizes and adequate accounting for confounding, is needed to provide accurate information for women of childbearing age and practitioners to guide policy and ensure that appropriate funding, support and follow-up are in place.

PROSPERO REGISTRATION NUMBER

CRD42022307992.

Beyond a simple cause and effect relationship: Exploring the long-term outcomes of children prenatally exposed to opioids and other substances

The long-term outcomes of children exposed to opioids and other substances in utero, specifically those diagnosed with Neonatal Abstinence Syndrome (NAS), present a complex interaction of different factors. First, NAS and its clinical presentation will be defined, then summarized will be an overview of NAS prevalence, recent trends, and significance of NAS in the context of the rising synthetic opioid and polysubstance use. Highlighted will also be the identified risk factors for NAS, especially regarding the role of environmental and psychosocial stressors during pregnancy. Finally, reviewed will be the existing NAS literature, including its gaps and limitations, and suggested recommendations for future research and policy considerations for improving care for children and families impacted by NAS.

The Association Between Prenatal Maternal Stress and Adolescent Affective Outcomes is Mediated by Childhood Maltreatment and Adolescent Behavioral Inhibition System Sensitivity

Prenatal maternal stress is linked to offspring outcomes; however, there is little research on adolescents, behavioral, transdiagnostic outcomes, or the mechanisms through which relations operate. We examined, in N = 268 adolescents (Mage = 15.31 years; SD = 1.063; 57.8% boys) whether prenatal maternal stress is associated with adolescent affective outcomes; whether this association is mediated, serially, by childhood home atmosphere and adolescent behavioral inhibition system (BIS) sensitivity; and whether mediational effects are moderated by adolescent attention-deficit/hyperactivity disorder or maternal internalizing symptomology. Prenatal maternal daily stress and major life events were associated with adolescent outcomes through childhood negative atmosphere/neglect and BIS sensitivity, with no evidence of moderation. Results have implications regarding the effect of prenatal maternal stress on offspring outcomes and regarding corresponding sensitive periods.

Neurodevelopmental outcomes in children prenatally exposed to opioid maintenance treatment: A population-based study

BACKGROUND AND OBJECTIVES

Opioid maintenance treatment (OMT), with methadone or buprenorphine, is a key approach for managing opioid use disorder (OUD) during pregnancy. Despite buprenorphine's superior short-term outcomes, its long-term effects remain understudied. This study aims to evaluate the effects of prenatal OMT exposure on the incidence of childhood neurodevelopmental disorders (NDDs) considering timing effect.

METHODS

A retrospective cohort study using Rhode Island Medicaid data linked to vital statistics from 2008 to 2018 was conducted. The study included pregnancies having live birth from 2008 to 2016 with continuous Medicaid insurance and OUD diagnosis within 3 months preceding conception until delivery. At least one buprenorphine dispensing or a claim of methadone was required for exposure definition. Exposure was evaluated during early (0-90 days) or late (>90 days) gestation, or at any pregnancy phase. NDDs, including autism, attention-deficit/hyperactivity disorder (ADHD), learning disabilities, speech/language disorders, developmental coordination disorder, intellectual disability, and behavioral disorders, were identified using validated algorithms. Applying Cox proportional-hazard models with propensity score overlap weighting, adjusted hazard ratios (aHR) were calculated, mitigating potential confounders. Children were followed up from birth until NDD diagnosis, disenrollment, or study end.

RESULTS

Of 416 mother-child dyads with OUD, 40% used methadone and 20% had buprenorphine exposure during pregnancy. NDDs were observed in 36% of children with early methadone exposure compared to 17% in the early buprenorphine exposed group (aHR: 2.75; 95% confidence interval [CI]: 1.42-5.35). Further comparison to late buprenorphine exposure, late methadone exposure was associated with higher NDD risk (aHR: 2.05; 95% CI: 1.09-3.86). Compared to unexposed group, children exposed to methadone during early and late periods showed higher NDD incidences (aHR: 2.33; 95% CI: 1.51-3.60 and aHR: 2.42; 95% CI: 1.54-3.80, respectively).

DISCUSSION

The study suggests that buprenorphine is a good treatment option for OUD during pregnancy due to minimal long-term neurodevelopmental impacts on children. However, further extensive research is necessary to rule-out potential confounding.

An introduction to the HEALthy Brain and Child Development Study (HBCD) study

The fundamental organization of the human brain is established before birth, with rapid growth continuing over the first postnatal years. Children exposed before or after birth to various biological (e.g., substance exposure) or psychosocial hazards (e.g., maltreatment) are at elevated likelihood of deviating from a typical developmental trajectory, which in turn can be associated with psychological, behavioral, and physical health sequelae. In the HEALthy Brain and Child Development (HBCD) Study, a multi-site prospective longitudinal cohort study, brain, physical, biological, cognitive, behavioral, social, and emotional development is being examined starting in pregnancy and planned through age 10 (data are sampled at varying degrees of granularity depending on age, with more dense sampling earlier in life). HBCD aims to determine the short- and long-term impacts of a variety of both harmful and protective factors, including prenatal substance use, on developmental trajectories through early childhood. Organized as a nationwide consortium across 27 sites, the HBCD Study will collect multimodal data that will be made publicly available on a yearly basis, through a data use application and approval process. Here we provide an overview of the HBCD Study design, sampling, protocol development, and data management. Data collected through HBCD will be fundamental to informing future prenatal and early childhood interventions and policies to promote wellbeing and resilience in all children.

The effects of prenatal exposure to opioids on early childhood development: context matters most

INTRODUCTION

The opioid crisis has brought an increasing focus on the long-term outcomes of children following prenatal opioid exposure. Evidence to date has been conflicting, which has caused confusion and concern amongst parents, caregivers, social service providers, medical providers and policy makers.

METHODS

This review systematically evaluated the highest quality studies relating prenatal exposure to opioids with early childhood developmental outcomes. It focused on developmental outcomes as measured by the Bayley Scales of Infant and Toddler Development, encompassing cognitive, motor, and psychosocial domains of child development.

RESULTS

Although several articles reported correlations between prenatal opioid exposure and poor early childhood developmental outcomes, these relationships were no longer statistically significant after adjusting for socio-environmental factors.

CONCLUSION

Additional research is needed to determine the extent of any relationship of socio-environmental factors with early childhood development in children prenatally exposed to opioids. This review suggests that socio-environmental factors may be significantly related to poor early childhood outcomes in the presence of prenatal opioid exposure.

Neuroimaging of opioid effects in humans across conditions of acute administration, chronic pain therapy, and opioid use disorder

Evidence of central nervous system (CNS) exogenous opioid effects in humans has been primarily gained through neuroimaging of three participant populations: individuals after acute opioid administration, those with opioid use disorder (OUD), and those with chronic pain receiving opioid therapy. In both the brain and spinal cord, opioids alter processes of pain, cognition, and reward. Opioid-related CNS effects may persist and accumulate with longer opioid use duration. Meanwhile, opioid-induced benefits versus risks to brain health remain unclear. This review article highlights recent accumulating evidence for how exogenous opioids impact the CNS in humans. While investigation of CNS opioid effects has remained largely disparate across contexts of opioid acute administration, OUD, and chronic pain opioid therapy, integration across these contexts may enable advancement toward effective interventions.

Prenatal Opioid Exposure and Risk for Adverse Brain and Motor Outcomes in Infants Born Premature

OBJECTIVE

To compare brain magnetic resonance imaging (MRI) biomarkers and neurodevelopmental test scores in infants born preterm with and without prenatal opioid exposure (POE).

STUDY DESIGN

We examined 395 preterm infants (≤32 weeks gestational age) who had term-equivalent brain MRIs, composite scores from the Bayley Scales of Infant and Toddler Development-III at 2 years corrected age, and POE data. MRI parameters included total/regional brain volumes and severe punctate white matter lesions (PWMLs). We conducted bivariable analysis and multivariable logistic regression analyses.

RESULTS

The mean ± SD gestational age was 29.3 ± 2.5 weeks; 35 (8.9%) had POE and 20 (5.1%) had severe PWML. Compared with unexposed infants, those with POE exhibited higher rates of severe PWML (17.1% vs 3.9%, respectively; P = .002); findings remained significant with an OR of 4.16 (95% CI, 1.26-13.68) after adjusting for confounders. On mediation analysis, the significant relationship between POE and severe PWML was not indirectly mediated through preterm birth/gestational age (OR, 0.93; 95% CI, 0.78-1.10), thus suggesting the association was largely driven by a direct adverse effect of POE on white matter. In multivariable analyses, POE was associated with a significantly lower score by -6.2 (95% CI, -11.8 to -0.6) points on the Bayley Scales of Infant and Toddler Development-III Motor subscale compared with unexposed infants.

CONCLUSIONS

POE was associated with severe PWML; this outcome may be a direct effect of POE rather than being mediated by premature birth. POE was also associated with worse motor development. Continued follow-up to understand the long-term effects of POE is warranted.

Effects of prenatal opioid exposure on infant sympathetic and parasympathetic nervous system activity

Prenatal opioid exposure has been associated with developmental problems, including autonomic nervous system dysregulation. However, little is known about the effects of prenatal opioid exposure on the autonomic nervous system beyond the first days of life, particularly across both the parasympathetic and sympathetic branches, and when accounting for exposure to other substances. The present study examined the effects of prenatal exposure to opioid agonist therapy (OAT, e.g., methadone) and other opioids on infant autonomic nervous system activity at rest and in response to a social stressor (the Still-Face Paradigm) at six months among 86 infants varying in prenatal opioid and other substance exposure. Results indicated that OAT and other opioids have unique effects on the developing autonomic nervous system that may further depend on subtype (i.e., methadone versus buprenorphine) and timing in gestation. Results are discussed in the context of theoretical models of the developing stress response system.

Opioid-induced dysbiosis of maternal gut microbiota during gestation alters offspring gut microbiota and pain sensitivity

There has been a rapid increase in neonates born with a history of prenatal opioid exposure. How prenatal opioid exposure affects pain sensitivity in offspring is of interest, as this may perpetuate the opioid epidemic. While few studies have reported hypersensitivity to thermal pain, potential mechanisms have not been described. This study posits that alterations in the gut microbiome may underly hypersensitivity to pain in prenatally methadone-exposed 3-week-old male offspring, which were generated using a mouse model of prenatal methadone exposure. Fecal samples collected from dams and their offspring were subjected to 16s rRNA sequencing. Thermal and mechanical pain were assessed using the tail flick and Von Frey assays. Transcriptomic changes in whole brain samples of opioid or saline-exposed offspring were investigated using RNA-sequencing, and midbrain sections from these animals were subjected to qPCR profiling of genes related to neuropathic and inflammatory pain pathways. Prenatal methadone exposure increased sensitivity to thermal and mechanical pain and elevated serum levels of IL-17a. Taxonomical analysis revealed that prenatal methadone exposure resulted in significant alterations in fecal gut microbiota composition, including depletion of Lactobacillus, Bifidobacterium, and Lachnospiracea sp and increased relative abundance of Akkermansia, Clostridium sensu stricto 1, and Lachnoclostridium. Supplementation of the probiotic VSL#3 in dams rescued hypersensitivity to thermal and mechanical pain in prenatally methadone-exposed offspring. Similarly, cross-fostering prenatally methadone-exposed offspring to control dams also attenuated hypersensitivity to thermal pain in opioid-exposed offspring. Modulation of the maternal and neonatal gut microbiome with probiotics resulted in transcriptional changes in genes related to neuropathic and immune-related signaling in whole brain and midbrain samples of prenatally methadone-exposed offspring. Together, our work provides compelling evidence of the gut-brain-axis in mediating pain sensitivity in prenatally opioid-exposed offspring.

Predicting child development and school readiness, at age 5, for Aboriginal and non-Aboriginal children in Australia's Northern Territory

BACKGROUND

Positive early development is critical in shaping children's lifelong health and wellbeing. Identifying children at risk of poor development is important in targeting early interventions to children and families most in need of support. We aimed to develop a predictive model that could inform early support for vulnerable children.

METHODS

We analysed linked administrative records for a birth cohort of 2,380 Northern Territory children (including 1,222 Aboriginal children) who were in their first year of school in 2015 and had a completed record from the Australian Early Development Census (AEDC). The AEDC measures early child development (school readiness) across five domains of development. We fitted prediction models, for AEDC weighted summary scores, using a Partial Least Square Structural Equation Model (PLS-SEM) considering four groups of factors-pre-pregnancy, pregnancy, known at birth, and child-related factors. We first assessed the models' internal validity and then the out-of-sample predictive power (external validity) using the PLSpredict procedure.

RESULT

We identified separate predictive models, with a good fit, for Aboriginal and non-Aboriginal children. For Aboriginal children, a significant pre-pregnancy predictor of better outcomes was higher socioeconomic status (direct, β = 0.22 and indirect, β = 0.16). Pregnancy factors (gestational diabetes and maternal smoking (indirect, β = -0.09) and child-related factors (English as a second language and not attending preschool (direct, β = -0.28) predicted poorer outcomes. Further, pregnancy and child-related factors partially mediated the effects of pre-pregnancy factors; and child-related factors fully mediated the effects of pregnancy factors on AEDC weighted scores. For non-Aboriginal children, pre-pregnancy factors (increasing maternal age, socioeconomic status, parity, and occupation of the primary carer) directly predicted better outcomes (β = 0.29). A technical observation was that variance in AEDC weighted scores was not equally captured across all five AEDC domains; for Aboriginal children results were based on only three domains (emotional maturity; social competence, and language and cognitive skills (school-based)) and for non-Aboriginal children, on a single domain (language and cognitive skills (school-based)).

CONCLUSION

The models give insight into the interplay of multiple factors at different stages of a child's development and inform service and policy responses. Recruiting children and their families for early support programs should consider both the direct effects of the predictors and their interactions. The content and application of the AEDC measurement need to be strengthened to ensure all domains of a child's development are captured equally.

Reproductive and developmental toxicity assessments of LPM3480392, a novel mu opioid receptor biased agonist in rats

Opioids remain the most powerful analgesics for moderate to severe pain but their clinical use, misuse and abuse has been an alarming medical problem, especially for those users at child-bearing age. Mu-opioid receptor (MOR) biased agonists have been suggested as superior alternatives with better therapeutic ratios. We recently discovered and characterized a novel MOR biased agonist, LPM3480392, which demonstrates robust analgesic effect, favorable pharmacokinetic performance, and mild respiratory suppression in vivo. To understand the safety profile of LPM3480392 on the reproductive system and embryonic development, this study evaluated the effects of LPM3480392 on the fertility and early embryonic development, embryo-fetal development, and pre- and postnatal development in rats. Results showed that LPM3480392 had mild effects on parental male and female animals, accompanied by subtle early embryonic loss and delayed ossification of fetal development during organogenesis period. In addition, although minor effects were found on normal developmental milestones and behaviors in the pups, there was no evidence of malformed effect. In conclusion, these results suggest that LPM3480392 has a favorable safety profile with only minor effects on the reproductive and developmental outcomes in animals, which support the development of LPM3480392 as a novel analgesic.

Adverse Childhood Experiences and Prescription Opioid Use During Pregnancy: An Analysis of the North and South Dakota PRAMS, 2019-2020

Objectives: This study assesses the association between adverse childhood experiences (ACEs) and prescription opioid use during pregnancy. Methods: This study uses data on 2,999 individuals from the 2019 and 2020 Pregnancy Risk Assessment Monitoring System (PRAMS) from North Dakota and South Dakota. The relationship between ACEs and prescription opioid use during pregnancy is examined using multiple logistic regression. Results: The prevalence of prescription opioid use increases alongside accumulating ACEs. Compared to those with no ACEs, recent mothers with three or more ACEs have a 2.4 greater odds of prescription opioid use during pregnancy (aOR [adjusted odds ratio] = 2.437; 95% CI [confidence interval] = 1.319, 4.503). Conclusion: Accumulating ACEs are associated with an increased risk of prescription opioid use during pregnancy. Additional research is needed better understand the mechanisms that link ACEs and prescription opioid use during pregnancy, as well as how to best support those with ACEs exposure in a trauma-informed manner to reduce the risk of substance use.

Outcomes of Babies with Opioid Exposure (OBOE): protocol of a prospective longitudinal cohort study

BACKGROUND

While the health, social, and economic impacts of opioid addiction on adults and their communities are well known, the impact of maternal opioid use on the fetus exposed in utero is less well understood.

METHODS

This paper presents the protocol of the ACT NOW Outcomes of Babies with Opioid Exposure (OBOE) Study, a multi-site prospective longitudinal cohort study of infants with antenatal opioid exposure and unexposed controls. Study objectives are to determine the impact of antenatal opioid exposure on brain development and neurodevelopmental outcomes over the first 2 years of life and explore whether family, home, and community factors modify developmental trajectories during this critical time period.

RESULTS

Primary outcomes related to brain development include cortical volumes, deep cerebral gray matter volumes, resting-state functional connectivity measures, and structural connectivity measures using diffusion tensor imaging. Primary neurodevelopmental outcomes include visual abnormalities, cognitive, language, and motor skills measured using the Bayley Scales of Infant Development and social-emotional and behavioral problems and competence measured by the Brief Infant-Toddler Social and Emotional Assessment.

CONCLUSIONS

The OBOE study has been designed to overcome challenges of previous studies and will help further understanding of the effects of antenatal opioid exposure on early infant development.

IMPACT

This study will integrate MRI findings and comprehensive neurodevelopmental assessments to provide early insights into the functional topography of the brain in this high-risk population and assess MRI as a potential biomarker. Rather than conducting neuroimaging at a single time point, the study will include serial MRI assessments from birth to 2 years, allowing for the examination of trajectories throughout this period of rapid brain development. While previous studies often have had limited information on exposures, this study will use umbilical cord assays to accurately measure amounts of opioids and other substances from 20 weeks of gestation to birth.

A 12-month follow-up of infant neurodevelopmental outcomes of prenatal opioid exposure and polysubstance use

BACKGROUND

Prenatal opioid exposure has been associated with developmental deficits during infancy, but the literature is limited by simple group comparisons and lack of appropriate controls. Previously published research with the current sample documented unique associations between prenatal opioid exposure and developmental outcomes at three and six months, but less is known about associations later in infancy.

METHOD

The current study examined pre- and postnatal opioid and polysubstance exposure as predictors of parent-reported developmental status at 12 months of age. Participants were 85 mother-child dyads, oversampled for mothers taking opioid treatment medications during pregnancy. Maternal opioid and polysubstance use were reported using the Timeline Follow-Back Interview during the third trimester of pregnancy or up to one month postpartum and updated through the child's first year of life. Seventy-eight dyads participated in a 12-month assessment, including 68 with parent-reported developmental status on Ages and Stages Questionnaire.

RESULTS

At 12 months, average developmental scores fell within normal ranges and prenatal opioid exposure was not significantly related to any developmental outcomes. However, more prenatal alcohol exposure was significantly related to worse problem-solving scores, and this relationship remained after controlling for adjusted age and other substance exposure.

CONCLUSION

Although findings await replication with larger samples and more comprehensive measures, results suggest that unique developmental risks of prenatal opioid exposure may not persist through the first year of life. Effects of prenatal exposure to co-occurring teratogens, such as alcohol, may become apparent as children exposed to opioids develop.

Prenatal anesthetic exposure and offspring neurodevelopmental outcomes—A narrative review

While it is common for pregnant women to take anesthesia during surgery, the effects of prenatal anesthesia exposure (PAE) on the long-term neurodevelopment of the offspring remain to be clarified. Preclinical animal research has shown that in utero anesthetic exposure causes neurotoxicity in newborns, which is mainly characterized by histomorphological changes and altered learning and memory abilities. Regional birth cohort studies that are based on databases are currently the most convenient and popular types of clinical studies. Specialized questionnaires and scales are usually employed in these studies for the screening and diagnosis of neurodevelopmental disorders in the offspring. The time intervals between the intrauterine exposure and the onset of developmental outcomes often vary over several years and accommodate a large number of confounding factors, which have an even greater impact on the neurodevelopment of the offspring than prenatal anesthesia itself. This narrative review summarized the progress in prenatal anesthetic exposure and neurodevelopmental outcomes in the offspring from animal experimental research and clinical studies and provided a brief introduction to assess the neurodevelopment in children and potential confounding factors.

Prenatal Opioid Exposure and Neurodevelopmental Outcomes

The opioid epidemic in the United States has resulted in a significant increase in opioid use disorder among pregnant women and a concomitant increase in the incidence of neonatal opioid withdrawal syndrome. The long-term consequences of prenatal opioid exposure on neurodevelopmental outcomes are not fully understood. Animal studies indicate increased neuronal apoptosis and decreased neuronal proliferation and myelination with opioid exposure in-utero. Meta-analyses of human studies suggest decreased cognition and psychomotor performance in infancy and deficits in cognition and language in preschool. However, current studies have primarily focused on heroin or methadone exposure and have been limited by small sample size, inadequate comparison groups, and the inability to account for additional risk factors and exposures such as polysubstance abuse, poor prenatal care, neonatal withdrawal and treatment with opioids, and unsupportive home environment. Future studies should aim to better understand the potential impact of these confounding factors on the neurodevelopmental trajectory of exposed infants. This review discusses the up-to-date literature, current gaps in knowledge, and considerations for future studies in the arena of prenatal opioid exposure and neurodevelopmental outcomes.

Stressful life events and prescription opioid use during pregnancy: findings from the 2019 pregnancy risk assessment monitoring system

OBJECTIVE

Prescription opioid use during pregnancy poses risk to maternal and infant health. However, there is limited research on proximate risk factors for prescription opioid use during pregnancy. This study aimed to evaluate the relationship between stressful life events experienced in the 12 months prior to birth and prescription opioid use during pregnancy.

METHODS

Data from the 2019 Pregnancy Risk Assessment Monitoring System were analyzed (N = 17,812 women who delivered a live birth in 2019). Logistic regression and multinomial logistic regression analyses were used to assess the association between levels of stressful life events (0, 1-2, 3-5, or 6+) on (1) prescription opioid use, (2) combined opioid use (mono- or poly-opioid use), and (3) patterns of opioid use (pain management, opioid misuse) during pregnancy while controlling for socio-demographic characteristics, patterns of substance use prior to pregnancy, and pregnancy-related characteristics.

RESULTS

Women with a greater accumulation of stressful life events in the 12 months prior to birth-especially 6 or more-had increased likelihood of prescription opioid use. Accumulating stressful life events were also associated with a higher risk of poly-opioid use, as well as using prescription opioids for pain management and patterns of opioid misuse.

CONCLUSION

Stressful life events are a risk factor for prescription opioid use during pregnancy. Considering the harms posed by both stressors and opioid use for maternal and infant wellbeing, future research should assess efforts to prevent and manage stressful life events to reduce opioid use during pregnancy.

Alterations of brain microstructures in a mouse model of prenatal opioid exposure detected by diffusion MRI

Growing opioid use among pregnant women is fueling a crisis of infants born with prenatal opioid exposure. A large body of research has been devoted to studying the management of opioid withdrawal during the neonatal period in these infants, but less substantive work has explored the long-term impact of prenatal opioid exposure on neurodevelopment. Using a translationally relevant mouse model of prenatal methadone exposure (PME), the aim of the study is to investigate the cerebral microstructural differences between the mice with PME and prenatal saline exposure (PSE). The brains of eight-week-old male offspring with either PME (n = 15) or PSE (n = 15) were imaged using high resolution in-vivo diffusion magnetic resonance imaging on a 9.4 Tesla small animal scanner. Brain microstructure was characterized using diffusion tensor imaging (DTI) and Bingham neurite orientation dispersion and density imaging (Bingham-NODDI). Voxel-based analysis (VBA) was performed using the calculated microstructural parametric maps. The VBA showed significant (p < 0.05) bilateral alterations in fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), radial diffusivity (RD), orientation dispersion index (ODI) and dispersion anisotropy index (DAI) across several cortical and subcortical regions, compared to PSE. Particularly, in PME offspring, FA, MD and AD were significantly higher in the hippocampus, dorsal amygdala, thalamus, septal nuclei, dorsal striatum and nucleus accumbens. These DTI-based results suggest widespread bilateral microstructural alterations across cortical and subcortical regions in PME offspring. Consistent with the observations in DTI, Bingham-NODDI derived ODI exhibited significant reduction in PME offspring within the hippocampus, dorsal striatum and cortex. NODDI-based results further suggest reduction in dendritic arborization in PME offspring across multiple cortical and subcortical regions. To our best knowledge, this is the first study of prenatal opioid exposure to examine microstructural organization in vivo. Our findings demonstrate perturbed microstructural complexity in cortical and subcortical regions persisting into early adulthood which could interfere with critical neurodevelopmental processes in individuals with prenatal opioid exposure.

Cerebral perfusion and neurological examination characterise neonatal opioid withdrawal syndrome: a prospective cohort study

OBJECTIVE

To test the hypothesis that cerebral blood flow (CBF) assessed with arterial spin labelling (ASL) MRI is increased and standardised neurological examination is altered in infants with neonatal opioid withdrawal syndrome (NOWS) compared with those without.

DESIGN

Prospective cohort study.

SETTING

Level IV neonatal intensive care unit and outpatient primary care centre.

PARTICIPANTS

Infants with NOWS receiving pharmacological treatment and unexposed controls matched for gestational age at birth and post-menstrual age at MRI.

MAIN OUTCOMES

CBF assessed by ASL on non-sedated 3-Tesla MRI and standardised Hammersmith Neonatal Neurological Examination (HNNE) within 14 days of birth.

RESULTS

Thirty infants with NOWS and 31 control infants were enrolled and included in the final analysis. Global CBF across the brain was higher in the NOWS group compared with controls (14.2 mL/100 g/min±5.5 vs 10.7 mL/100 g/min±4.3, mean±SD, Cohen's d=0.72). HNNE total optimality score was lower in the NOWS group compared with controls (25.9±3.6 vs 28.4±2.4, mean±SD, Cohen's d=0.81). A penalised logistic regression model including both CBF and HNNE items discriminated best between the two groups.

CONCLUSIONS

Increased cerebral perfusion and neurological examination abnormalities characterise infants with NOWS compared with those without intrauterine drug exposure and suggest prenatal substance exposure affects fetal brain development. Identifying neurological and neuroimaging characteristics of infants with NOWS can contribute to understanding mechanisms underlying later outcomes and to designing potential new treatments.

Evidence for the Normalization Effects of Medication for Opioid Use Disorder on Functional Connectivity in Neonates with Prenatal Opioid Exposure

Altered functional connectivity has been reported in infants with prenatal exposure to opioids, which significantly interrupts and influences endogenous neurotransmitter/receptor signaling during fetal programming. Better birth outcomes and long-term developmental outcomes are associated with medication for opioid use disorder (MOUD) during pregnancy, but the neural mechanisms underlying these benefits are largely unknown. We aimed to characterize effects of prenatal opioid/other drug exposure (PODE) and the neural basis for the reported beneficial effects of MOUD by examining neonatal brain functional organization. A cohort of 109 human newborns, 42 PODE, 39 with prenatal exposure to drugs excluding opioids (PDE), 28 drug-free controls (males and females) underwent resting-state fMRI at 2 weeks of age. To examine neural effects of MOUD, PODE infants were separated into subgroups based on whether mothers received MOUD (n = 31) or no treatment (n = 11). A novel heatmap analysis was designed to characterize PODE-associated functional connectivity alterations and MOUD-related effects, and permutation testing identified regions of interest with significant effects. PODE neonates showed alterations beyond those associated with PDE, particularly in reward-related frontal-sensory connectivity. MOUD was associated with a significant reduction of PODE-related alterations in key regions of endogenous opioid pathways including limbic and frontal connections. However, significant residual effects in limbic and subcortical circuitry were observed. These findings confirm altered brain functional organization associated with PODE. Importantly, widespread normalization effects associated with MOUD reveal, for the first time, the potential brain basis of the beneficial effects of MOUD on the developing brain and underscore the importance of this treatment intervention for better developmental outcomes.SIGNIFICANCE STATEMENT This is the first study to reveal the potential neural mechanisms underlying the beneficial effects on the neonate brain associated with MOUD during pregnancy. We identified both normalization and residual effects of MOUD on brain functional architecture by directly comparing neonates prenatally exposed to opioids with MOUD and those exposed to opioids but without MOUD. Our findings confirm altered brain functional organization associated with prenatal opioid exposure and demonstrate that although significant residual effects remain in reward circuitry, MOUD confers significant normalization effects on functional connectivity of regions associated with socioemotional development and reward processing. Together, our results highlight the importance of MOUD intervention for better neurodevelopmental outcomes.

Neural alterations in opioid-exposed infants revealed by edge-centric brain functional networks

Prenatal opioid exposure has been linked to adverse effects spanning multiple neurodevelopmental domains, including cognition, motor development, attention, and vision. However, the neural basis of these abnormalities is largely unknown. A total of 49 infants, including 21 opioid-exposed and 28 controls, were enrolled and underwent MRI (43 ± 6 days old) after birth, including resting state functional MRI. Edge-centric functional networks based on dynamic functional connections were constructed, and machine-learning methods were employed to identify neural features distinguishing opioid-exposed infants from unexposed controls. An accuracy of 73.6% (sensitivity 76.25% and specificity 69.33%) was achieved using 10 times 10-fold cross-validation, which substantially outperformed those obtained using conventional static functional connections (accuracy 56.9%). More importantly, we identified that prenatal opioid exposure preferentially affects inter- rather than intra-network dynamic functional connections, particularly with the visual, subcortical, and default mode networks. Consistent results at the brain regional and connection levels were also observed, where the brain regions and connections associated with visual and higher order cognitive functions played pivotal roles in distinguishing opioid-exposed infants from controls. Our findings support the clinical phenotype of infants exposed to opioids in utero and may potentially explain the higher rates of visual and emotional problems observed in this population. Finally, our findings suggested that edge-centric networks could better capture the neural differences between opioid-exposed infants and controls by abstracting the intrinsic co-fluctuation along edges, which may provide a promising tool for future studies focusing on investigating the effects of prenatal opioid exposure on neurodevelopment.

Ophthalmic outcomes in children exposed to opioid maintenance treatment in utero: A systematic review and meta-analysis

Opioid use disorder is a significant global issue and the rate of opioid use in women of childbearing age and pregnant women is on the rise. Whilst the adverse general health, cognitive, and neurodevelopmental outcomes of in utero exposure to opioids have been explored, there is a lack of prospective, controlled, longitudinal research into the ophthalmic outcomes. Existing research suggests that there is an association between prenatal exposure and future risk of abnormalities in visual functioning. This systematic review and meta-analysis analysed studies that measured eye abnormalities in infants or children exposed to opioid maintenance therapy in utero and compared them to non-opioid exposed controls. After considering the clinical findings, limitations of the studies, confounding factors, and quantitative analysis, a causal relationship between in utero opioid exposure and future eye abnormalities could not be confirmed. The implications of the findings and their clinical relevance, in addition to identified gaps for future research are also discussed in this paper.

Intrauterine drug exposure as a risk factor for cerebral palsy

AIM

To determine whether infants with intrauterine drug exposure (IUDE) are similarly at risk for cerebral palsy (CP) as other high-risk populations, whether CP classification differs based on IUDE status, and describe the association of CP with specific substances among exposed infants.

METHOD

This was a retrospective analysis of infants in a high-risk follow-up program (n=5578) between January 2014 and February 2018 with a history of IUDE or who received a CP diagnosis. CP rates were compared using two-sample z-tests. CP classification was assessed using Fisher's exact, Cochran-Armitage, and Wilcoxon rank-sum tests. Models for CP risk were assessed using multivariable logistic regression.

RESULTS

Among all infants with IUDE (n=1086), 53.8% were male with a mean (SD) birth gestational age of 36.8 (3.6) weeks. Among unexposed infants with CP (n=259), 54.4% were male with a mean (SD) birth gestational age of 29.9 (5.7) weeks. Opioids were the most common exposure (93.7%) of all infants with IUDE. The CP rate in the IUDE (5.2%) and unexposed (5.7%) high-risk populations were not significantly different (p=0.168), nor were there differences in CP typology, topography, or severity between exposed (n=57) and unexposed (n=259) infants (all p>0.05). In patients with IUDE and after controlling for established CP risk factors, the observed odds of CP varied among substances.

INTERPRETATION

We suggest that IUDE should be considered a 'newborn-detectable risk' in the guidelines for the early detection of CP.

Substance Use in Pregnancy: Identifying Stigma and Improving Care

This review examines the impact of stigma on pregnant people who use substances. Stigma towards people who use drugs is pervasive and negatively impacts the care of substance-using people by characterizing addiction as a weakness and fostering beliefs that undermine the personal resources needed to access treatment and recover from addiction, including self-efficacy, help seeking and belief that they deserve care. Stigma acts on multiple levels by blaming people for having a problem and then making it difficult for them to get help, but in spite of this, most pregnant people who use substances reduce or stop using when they learn they are pregnant. Language, beliefs about gender roles, and attitudes regarding fitness for parenting are social factors that can express and perpetuate stigma while facilitating punitive rather than therapeutic approaches. Because of stigmatizing attitudes that a person who uses substances is unfit to parent, pregnant people who use substances are at heightened risk of being screened for substance use, referred to child welfare services, and having their parental rights taken away; these outcomes are even more likely for people of color. Various treatment options can successfully support recovery in substance-using pregnant populations, but treatment is underutilized in all populations including pregnant people, and more knowledge is needed on how to sustain engagement in treatment and recovery activities. To combat stigma when working with substance-using pregnant people throughout the peripartum period, caregivers should utilize a trauma-informed approach that incorporates harm reduction and motivational interviewing with a focus on building trust, enhancing self-efficacy, and strengthening the personal skills and resources needed to optimize health of the parent-baby dyad.

Co-occurrence of preconception maternal childhood adversity and opioid use during pregnancy: Implications for offspring brain development

Understanding of the effects of in utero opioid exposure on neurodevelopment is a priority given the recent dramatic increase in opioid use among pregnant individuals. However, opioid abuse does not occur in isolation-pregnant individuals abusing opioids often have a significant history of adverse experiences in childhood, among other co-occurring factors. Understanding the specific pathways in which these frequently co-occurring factors may interact and cumulatively influence offspring brain development in utero represents a priority for future research in this area. We highlight maternal history of childhood adversity (CA) as one such co-occurring factor that is more prevalent among individuals using opioids during pregnancy and which is increasingly shown to affect offspring neurodevelopment through mechanisms beginning in utero. Despite the high incidence of CA history in pregnant individuals using opioids, we understand very little about the effects of comorbid prenatal opioid exposure and maternal CA history on fetal brain development. Here, we first provide an overview of current knowledge regarding effects of opioid exposure and maternal CA on offspring neurodevelopment that may occur during gestation. We then outline potential mechanistic pathways through which these factors might have interactive and cumulative influences on offspring neurodevelopment as a foundation for future research in this area.

Improving translational relevance: The need for combined exposure models for studying prenatal adversity

Prenatal environmental adversity is a risk factor for neurodevelopmental disorders (NDDs), with the neuroimmune environment proposed to play a role in this risk. Adverse maternal exposures are associated with cognitive consequences in the offspring that are characteristics of NDDs and simultaneous neuroimmune changes that may underlie NDD risk. In both animal models and human studies the association between prenatal environmental exposure and NDD risk has been shown to be complex. Maternal overnutrition/obesity and opioid use are two different examples of complex exposure epidemics, each with their own unique comorbidities. This review will examine maternal obesity and maternal opioid use separately, illustrating the pervasive comorbidities with each exposure to argue a need for animal models of compound prenatal exposures. Many of these comorbidities can impact neuroimmune function, warranting systematic investigation of combined exposures to begin to understand this complexity. While traditional approaches in animal models have focused on modeling a single prenatal exposure or second exposure later in life, a translational approach would begin to incorporate the most prevalent co-occurring prenatal exposures. Long term follow-up in humans is extremely challenging, so animal models can provide timely insight into neurodevelopmental consequences of complex prenatal exposures. Animal models that represent this translational context of comorbid exposures behind maternal obesity or comorbid exposures behind maternal opioid use may reveal potential synergistic neuroimmune interactions that contribute to cognitive consequences and NDD risk. Finally, translational co-exposure models can identify concerning exposure combinations to guide treatment in complex cases, and identify high risk children starting in the prenatal period where early interventions improve prognosis.

The harms of punishing substance use during pregnancy

As rates of substance use have increased in the United States, rates of substance-involved pregnancies have also been on the rise, inspiring new civil policies designed to punish pregnant and parenting individuals who engage in substance use or are living with an untreated substance use disorder. Proponents of punitive civil policies argue that such policies will deter substance use behaviors and/or that substance use during pregnancy deserves punishment for harming the fetus. Current scientific evidence invalidates both claims, offering compelling evidence that punitive civil policies often worsen the harms of substance use for both parent and child. In this commentary, we review this evidence and explain how punitive policies that threaten child removal and the termination of parental rights exacerbate the very problems they are ostensibly designed to reduce. Rather than coercive and punitive responses, families affected by substance use need greater access to affordable, evidence-based treatment as well as services that address the structural and relational concerns underlying substance use. Above all, responses to perinatal substance use in both policy and practice should prioritize keeping families together.

Prenatal opioid exposure is associated with smaller brain volumes in multiple regions

BACKGROUND

The impact of prenatal opioid exposure on brain development remains poorly understood.

METHODS

We conducted a prospective study of term-born infants with and without prenatal opioid exposure. Structural brain MRI was performed between 40 and 48 weeks postmenstrual age. T2-weighted images were processed using the Developing Human Connectome Project structural pipeline. We compared 63 relative regional brain volumes between groups.

RESULTS

Twenty-nine infants with prenatal opioid exposure and 42 unexposed controls were included. The groups had similar demographics, except exposed infants had lower birth weights, more maternal smoking and maternal Hepatitis C, fewer mothers with a college degree, and were more likely non-Hispanic White. After controlling for sex, postmenstrual age at scan, birth weight, and maternal education, exposed infants had significantly smaller relative volumes of the deep gray matter, bilateral thalamic ventrolateral nuclei, bilateral insular white matter, bilateral subthalamic nuclei, brainstem, and cerebrospinal fluid. Exposed infants had larger relative volumes of the right cingulate gyrus white matter and left occipital lobe white matter.

CONCLUSIONS

Infants with prenatal opioid exposure had smaller brain volumes in multiple regions compared to controls, with two regions larger in the opioid-exposed group. Further research should focus on the relative contributions of maternal opioids and other exposures.

IMPACT

Prenatal opioid exposure is associated with developmental and behavioral consequences, but the direct effects of opioids on the developing human brain are poorly understood. Prior small studies using MRI have shown smaller regional brain volumes in opioid-exposed infants and children. After controlling for covariates, infants with prenatal opioid exposure scanned at 40-48 weeks postmenstrual age had smaller brain volumes in multiple regions compared to controls, with two regions larger in the opioid-exposed group. This adds to the literature showing potential impact of prenatal opioid exposure on the developing brain.

Effects of prenatal opioid exposure on functional networks in infancy

Prenatal opioid exposure has been linked to altered neurodevelopment and visual problems such as strabismus and nystagmus. The neural substrate underlying these alterations is unclear. Resting-state functional connectivity MRI (rsfMRI) is an advanced and well-established technique to evaluate brain networks. Few studies have examined the effects of prenatal opioid exposure on resting-state network connectivity in infancy. In this pilot study, we characterized network connectivity in opioid-exposed infants (n = 19) and controls (n = 20) between 4–8 weeks of age using both a whole-brain connectomic approach and a seed-based approach. Prenatal opioid exposure was associated with differences in distribution of betweenness centrality and connection length, with positive connections unique to each group significantly longer than common connections. The unique connections in the opioid-exposed group were more often inter-network connections while unique connections in controls and connections common to both groups were more often intra-network. The opioid-exposed group had smaller network volumes particularly in the primary visual network, but similar network strength as controls. Network topologies as determined by dice similarity index were different between groups, particularly in visual and executive control networks. These results may provide insight into the neural basis for the developmental and visual problems associated with prenatal opioid exposure.

Infant neurodevelopmental outcomes of prenatal opioid exposure and polysubstance use

BACKGROUND

Prenatal opioid exposure has been linked to adverse birth outcomes and delays in infant development. Existing literature is limited by a simple group-differences approach as well as inadequate controls for sociodemographic factors and polysubstance exposure co-occurring with prenatal opioid use.

METHOD

The current study assessed cumulative opioid exposure (duration of prescribed and illicit opioid use) as a predictor of infant birth outcomes and mother-reported developmental status at three and six months of age, controlling for polysubstance exposure. Participants were predominantly low-income pregnant and peripartum women, oversampled for mothers receiving medication-assisted treatment (MAT) for opioid use disorder. Prenatal opioid and non-opioid substance use were reported by mothers using a Timeline Follow-Back Interview completed during the third trimester and updated postnatally (infant age six months).

RESULTS

Developmental scores were in the normal range. However, total opioid exposure was positively related to premature birth and inversely related to mother-reported developmental status in specific domains. Associations with three-month fine motor skills and six-month communication skills were robust to controls for polysubstance exposure and sociodemographic covariates.

CONCLUSIONS

Results suggest unique effects of prenatal opioid exposure on the early development of fine motor and communication skills. Similar findings were obtained for prescribed and illicit opioid use, underscoring developmental risks of both MAT and untreated substance use. Exploratory analyses investigating type and timing of MAT suggest directions for future research.

Association Between Prenatal Opioid Exposure and Neurodevelopmental Outcomes in Early Childhood: A Retrospective Cohort Study

INTRODUCTION

Several studies have reported increasing prevalence of prescription opioid use among pregnant women. However, little is known regarding the effects of maternal opioid use on neurodevelopmental disorders in early childhood in pregnant women with no evidence of opioid use disorders or drug dependence.

OBJECTIVE

The aim of this study was to quantify the association between prenatal opioid exposure from maternal prescription use and neurodevelopmental outcomes in early childhood.

METHODS

This retrospective study included pregnant women aged 12-55 years and their live-birth infants born from 2010 to 2012 present in Optum's deidentified Clinformatics® Data Mart database. Eligible infants born to mothers without opioid use disorders or drug dependence were followed till occurrence of neurodevelopmental disorders, loss to follow-up, or study end (December 31, 2017), whichever came first. Propensity score by fine stratification was applied to adjust for confounding by demographic characteristics, obstetric characteristics, maternal comorbid mental and pain conditions, and measures of burden of illnesses and to obtain adjusted hazard ratios (HR) and 95% confidence intervals (CI). Exposed and unexposed infants were compared on the incidence of neurodevelopmental disorders.

RESULTS

Of 24,910 newborns, 7.6% (1899) were prenatally exposed to prescription opioids. Overall, 1562 children were diagnosed with neurodevelopmental disorders, with crude incidence rates of 2.9 per 100 person-years in exposed children versus 2.5 per 100 person-years in unexposed children. After adjustment, we observed no association between fetal opioid exposure and the risk of neurodevelopmental disorders (HR 1.10; 95% CI 0.92-1.32). However, increased risk of neurodevelopmental disorders were observed in children with longer cumulative exposure duration (HR 1.70; 95% CI 1.05-2.96) or high cumulative opioid doses (HR 1.22; 95% CI 1.01-1.54).

CONCLUSION AND RELEVANCE

In pregnant women without opioid use disorders or drug dependence, maternal opioid use was not associated with increased risk of neurodevelopmental disorders in early childhood. However, increased risks of early neurodevelopmental disorders were observed in children born to women receiving prescription opioids for longer duration and at higher doses during pregnancy.

Fifty Years of Research on Prenatal Substances: Lessons Learned for the Opioid Epidemic

Current efforts to design research on developmental effects of prenatal opioid exposure can benefit from knowledge gained from 50 years of studies of fetal alcohol and prenatal drug exposures such as cocaine. Scientific advances in neurobiology, developmental psychopathology, infant assessments, genetics, and imaging support the principles of developmental neurotoxicology that guide research in prenatal exposures. Important to research design is accurate assessment of amount, frequency, and timing of exposure which benefits from accurate self-report and biomarkers of exposure. Identifying and control of pre- and postnatal factors that impact development are difficult and dependent on appropriate research design and selection of comparison groups and measurement of confounding, mediating, and moderating variables. Polysubstance exposure has increased due to the number of prescribed and nonprescribed substances used by pregnant women and varying combinations of drugs may have differential effects on the outcome. Multiple experimental and clinical assessments of infant behavior have been developed but predicting outcome before 18-24 months of age remains difficult. With some exceptions, prenatal substance exposure effect sizes have been small, and cognitive and behavioral effects tend to be specific rather than global. Studies require large sample sizes, adequate retention, and support for social services in at-risk samples. The ethical and legal contexts and stigma associated with drug/alcohol use disorder should be considered in order to prevent harm to families in research programs. Recognition of the pervasive use of addictive substances in this nation should lead to broad scientific efforts to understand how substances affect child outcomes and to initiate prevention and intervention where needed.

Principles for Guiding the Selection of Early Childhood Neurodevelopmental Risk and Resilience Measures: HEALthy Brain and Child Development Study as an Exemplar

The vast individual differences in the developmental origins of risk and resilience pathways combined with sophisticated capabilities of big data science increasingly point to the imperative of large, neurodevelopmental consortia to capture population heterogeneity and key variations in developmental trajectories. At the same time, such large-scale population-based designs involving multiple independent sites also must weigh competing demands. For example, the need for efficient, scalable assessment strategies must be balanced with the need for nuanced, developmentally sensitive phenotyping optimized for linkage to neural mechanisms and specification of common and distinct exposure pathways. Standardized epidemiologic batteries designed for this purpose such as PhenX (consensus measures for Phenotypes and eXposures) and the National Institutes of Health (NIH) Toolbox provide excellent "off the shelf" assessment tools that are well-validated and enable cross-study comparability. However, these standardized toolkits can also constrain ability to leverage advances in neurodevelopmental measurement over time, at times disproportionately advantaging established measures. In addition, individual consortia often expend exhaustive effort "reinventing the wheel," which is inefficient and fails to fully maximize potential synergies with other like initiatives. To address these issues, this paper lays forth an early childhood neurodevelopmental assessment strategy, guided by a set of principles synthesizing developmental and pragmatic considerations generated by the Neurodevelopmental Workgroup of the HEALthy Brain and Child Development (HBCD) Planning Consortium. These principles emphasize characterization of both risk- and resilience-promoting processes. Specific measurement recommendations to HBCD are provided to illustrate application. However, principles are intended as a guiding framework to transcend any particular initiative as a broad neurodevelopmentally informed, early childhood assessment strategy for large-scale consortia science.

Prenatal opioid exposure - Increasing evidence of harm

Prenatal opioid exposure adversely impacts upon fetal growth and places the newborn at risk of neonatal opioid withdrawal. The severity and duration of opioid withdrawal cannot be predicted in the individual baby and may be contributed to by other drugs including benzodiazepines and alcohol as well as cigarette smoking. Mitigating factors include breastfeeding, rooming in and absence of maternal polypharmacy. Less well recognised are a variety of other complications associated with prenatal opioid exposure including epigenetic changes, effects on neurophysiological function and structural alterations to the developing brain. The visual system is significantly affected, with changes to both clinical and electrophysiological function persisting at least to mid-childhood. Longer term neurodevelopmental and behavioural outcomes are confounded by multiple factors including poverty, parent-child interaction and small study numbers, but systematic reviews consistently demonstrate poorer outcomes for those children and young people prenatally exposed to opioids. Crucially, manifestation of neonatal withdrawal is not a prerequisite for important long term problems including behavioural, emotional or motor function disorder, sensory or speech disorder, strabismus and nystagmus. A body of evidence supports an independent adverse effect of prenatal opioid exposure upon fetal brain development, mediated via a systemic neuro-inflammatory process. Children prenatally exposed to opioids should remain under appropriate follow up, at least until school entry, as difficulties may only become apparent in mid-childhood. Future studies of the management of opioid use disorder in pregnancy, including maintenance methadone, must include longer term outcomes for the baby.

Prenatal Opioid Exposure Enhances Responsiveness to Future Drug Reward and Alters Sensitivity to Pain: A Review of Preclinical Models and Contributing Mechanisms

The opioid crisis has resulted in an unprecedented number of neonates born with prenatal opioid exposure (POE); however, the long-term effects of POE on offspring behavior and neurodevelopment remain relatively unknown. The advantages and disadvantages of the various preclinical POE models developed over the last several decades are discussed in the context of clinical and translational relevance. Although considerable and important variability exists among preclinical models of POE, the examination of these preclinical models has revealed that opioid exposure during the prenatal period contributes to maladaptive behavioral development as offspring mature including an altered responsiveness to rewarding drugs and increased pain response. The present review summarizes key findings demonstrating the impact of POE on offspring drug self-administration (SA), drug consumption, the reinforcing properties of drugs, drug tolerance, and other reward-related behaviors such as hypersensitivity to pain. Potential underlying molecular mechanisms which may contribute to this enhanced addictive phenotype in POE offspring are further discussed with special attention given to key brain regions associated with reward including the striatum, prefrontal cortex (PFC), ventral tegmental area (VTA), hippocampus, and amygdala. Improvements in preclinical models and further areas of study are also identified which may advance the translational value of findings and help address the growing problem of POE in clinical populations.