Brain morphology in school-aged children with prenatal opioid exposure: A structural MRI study

Neonatal Abstinence Syndrome: Review of Epidemiology, Care Models, and Current Understanding of Outcomes

The incidence of neonatal abstinence syndrome owing to prenatal opioid exposure has grown rapidly in recent decades and it disproportionately affects rural, non-white, and public insurance-dependent populations. Treatment consists of pharmacologic and nonpharmacologic interventions with wide variability in approaches across the United States. Standardizing clinical assessment, minimizing unnecessary interruptions, and prioritizing nonpharmacologic and family-centered care seems to improve hospital outcomes. Neonatal abstinence syndrome may have long-term developmental and biological effects, but understanding is limited owing in part confounding biosocial factors. Early intervention and longitudinal support of the infant and family promote better outcomes.

White Matter Injury and Structural Anomalies in Infants with Prenatal Opioid Exposure

Previous studies have not found structural injury or brain malformations in infants and children with prenatal opioid exposure. As part of an ongoing study evaluating neuroimaging in infants with prenatal opioid exposure, we reviewed structural brain MR imaging in 20 term infants with prenatal opioid exposure and 20 term controls at 4-8 weeks of age. We found that 8 of the 20 opioid-exposed infants had punctate white matter lesions or white matter signal abnormality on structural MR imaging, and 2 of the opioid-exposed infants had a septopreoptic fusion anomaly. No controls had white matter injury or structural malformations. Our findings underscore the importance of clinical neurodevelopmental follow-up and the need for more comprehensive imaging and long-term outcomes research following prenatal opioid exposure.

Educational achievement at age 9.5 years of children born to mothers maintained on methadone during pregnancy

Recent research shows that preschool children born to opioid-dependent mothers are at increased risk for cognitive, psychomotor, attention, and social-emotional adjustment problems. But very little is known about their school-age functioning, particularly their educational achievement. This analysis examined the educational outcomes of a regional cohort of 100 prenatally methadone-exposed children who were prospectively studied from birth to age 9.5 years alongside a comparison group of 110 randomly identified non-exposed children born between 2003 and 2008. At age 9.5, as part of a comprehensive neurodevelopmental evaluation, children's teachers rated their achievement across the school curriculum, and children completed the Woodcock Johnson-III Tests of Achievement (WJ-III). Detailed information about the birth mother's social background, pregnancy substance use, and mental health was also collected during pregnancy/at term. Infant clinical data were collected after birth. Methadone-exposed children performed less well than non-exposed children across seven school curriculum areas rated by teachers (ps ≤.001), performed less well than non-exposed children on all reading and mathematics subtests of the WJ-III, and had higher rates of any educational delay on the WJ-III (57% vs. 15%), OR = 7.47 (3.71-15.02). Results were similar when children with severe intellectual impairment were excluded. After adjusting for confounding factors, methadone-exposed children had increased odds of educational delay, but this was only marginally significant (OR = 3.62, [1.01-13.01], p = .049). Maternal educational attainment level (OR = 0.69, [0.50-0.89], p = .006), and maternal benzodiazepine use during pregnancy (OR = 2.70 [1.03-7.12], p = .044) were also associated with later educational risk. Findings suggest that children born to opioid-dependent women enrolled in methadone maintenance are at high risk of educational delay by age 9.5 years. Children's academic difficulties appeared to reflect the effects of both adverse prenatal exposures and postnatal social risk.

Salivary cortisol levels relate to cognitive performance in children prenatally exposed to methadone or buprenorphine

Opioid maintenance therapy (OMT) is generally recommended for pregnant opioid-dependent women. However, much is still unknown about the potential long-term effects of prenatal methadone and buprenorphine exposure. This study explored the long-term effects of prenatal methadone and buprenorphine exposure in a cohort (n = 41) of children, aged 9-11 years, using the Wechsler Abbreviated Scale of Intelligence (WASI) to measure cognitive development and salivary cortisol samples to measure HPA-axis activity. Prenatally exposed children scored significantly lower on all four subtests of WASI (vocabulary, similarities, block design, and matrix reasoning), compared to a comparison group (all p < .05). No group differences were found for salivary cortisol levels or cortisol reactivity levels (all p > .05). Cortisol levels significantly predicted matrix reasoning scores for the OMT group, β = -65.58, t(20) = 15.70, p = .02. Findings suggest that prenatal exposure to methadone or buprenorphine does not have long-term effects on children's HPA-axis functioning. However, since children of women in OMT scored significantly lower on tasks of cognitive function, careful follow-up throughout the school years and across adolescence is recommended.

Visual and oculomotor outcomes in children with prenatal opioid exposure

PURPOSE OF REVIEW

To summarize the visual and oculomotor outcomes in children with prenatal opioid exposure and review the effects of opioids on the developing central nervous system.

RECENT FINDINGS

Animal models and imaging studies in children suggest that prenatal opioid exposure may affect neuronal survival and result in delayed maturation of white matter tracts and decreased volumes in certain brain areas. Visual evoked potential testing in children demonstrates delayed maturation of the afferent visual system in opioid-exposed groups compared with controls, though 'catch-up' development is seen with longitudinal follow-up. Strabismus and nystagmus are also more common in exposed children, and these findings appear to persist.

SUMMARY

As rates of opioid dependence and prenatal opioid exposure continue to increase, it is important to evaluate the short-term and long-term effects of opioids on the developing visual system. An understanding of these risks is important when counseling the parents or guardians of opioid-exposed children, though larger studies with more long-term follow-up will improve our prognostic abilities.

Novel biomarkers to assess in utero effects of maternal opioid use: First steps toward understanding short- and long-term neurodevelopmental sequelae

Maternal opioid use disorder is common, resulting in significant neonatal morbidity and cost. Currently, it is not possible to predict which opioid-exposed newborns will require pharmacotherapy for neonatal abstinence syndrome. Further, little is known regarding the effects of maternal opioid use disorder on the developing human brain. We hypothesized that novel methodologies utilizing fetal central nervous system-derived extracellular vesicles isolated from maternal blood can address these gaps in knowledge. Plasma from opioid users and controls between 9 and 21 weeks was precipitated and extracellular vesicles were isolated. Mu opioid and cannabinoid receptor levels were quantified. Label-free proteomics studies and unbiased small RNA next generation sequencing was performed in paired fetal brain tissue. Maternal opioid use disorder increased mu opioid receptor protein levels in extracellular vesicles independent of opioid equivalent dose. Moreover, cannabinoid receptor levels in extracellular vesicles were upregulated with opioid exposure indicating cross talk with endocannabinoids. Maternal opioid use disorder was associated with significant changes in extracellular vesicle protein cargo and fetal brain micro RNA expression, especially in male fetuses. Many of the altered cargo molecules and micro RNAs identified are associated with adverse clinical neurodevelopmental outcomes. Our data suggest that assays relying on extracellular vesicles isolated from maternal blood extracellular vesicles may provide information regarding fetal response to opioids in the setting of maternal opioid use disorder. Prospective clinical studies are needed to evaluate the association between extracellular vesicle biomarkers, risk of neonatal abstinence syndrome and neurodevelopmental outcomes.

Prenatal drug exposure from infancy through emerging adulthood: Results from neuroimaging

Prenatal drug exposure may have important repercussions across the lifespan for cognition and behavior. While alcohol is a recognized teratogen, the influences of other substances may also be substantial. The neural underpinnings of the influences of prenatal drug exposure have been examined using longitudinal approaches and multiple imaging techniques. Here we review the existing literature on the neural correlates of prenatal drug exposure. We focused the review on studies that have employed functional neuroimaging and electroencephalography and on substances other than alcohol. We also framed the review through the lens of four developmental life stages (infancy, childhood, adolescence and emerging adulthood). We included papers that have examined any drug use, including tobacco, opiates, cocaine, marijuana, methamphetamines, or polysubstance use. Data suggest that prenatal drug exposure has long-lasting, deleterious influences on cognition and reward processing in infancy and childhood that persist into adolescence and emerging adulthood and may underlie some behavioral tendencies, such as increased externalizing and risk-taking behaviors, seen in these groups.

After NAS

Mothers have used opioids for thousands of years but neonatal abstinence syndrome (NAS) or rather, survivors of NAS, is a modern phenomenon. Unrecognized and/or untreated opioid withdrawal was almost always fatal but with greater awareness and standardization of treatment, NAS is now an uncommon direct cause of infant death. However, opioids are now increasingly accessible and potent and the outcomes of children after the neonatal period are of great concern, especially when coupled with multiple other social and health risks. Complex individual, environmental and genetic factors need to be considered when assessing outcomes or future research for babies with NAS. Any intervention or research efforts must address these multifactorial complexities. This review will discuss pertinent post neonatal outcomes, including mortality, physical and mental health and social functioning of children with a history of NAS.

Early life opioid exposure and potential long-term effects

The long-term consequences of perinatal opioid exposure and subsequent development of neonatal opioid withdrawal syndrome is largely unknown and likely dependent on a multitude of factors, including co-morbid drug use, pre- and post-natal care, and individual factors including the maternal-infant relationship and home environment. This review summarizes the current literature from clinical and preclinical studies on perinatal opioid exposure, focusing on the consequences in the offspring. Although a large number of preclinical studies have been conducted examining the impact of prenatal opioid exposure, the models employed are not necessarily representative of clinical use patterns, making it challenging to translate these results to the impacted population. Use of more clinically-relevant models of perinatal opioid exposure are requisite for the development of improved pharmacological and behavioral treatment strategies to improve quality of life for this vulnerable population.

Prenatal exposures and infant brain: Review of magnetic resonance imaging studies and a population description analysis

Brain development is most rapid during the fetal period and the first years of life. This process can be affected by many in utero factors, such as chemical exposures and maternal health characteristics. The goal of this review is twofold: to review the most recent findings on the effects of these prenatal factors on the developing brain and to qualitatively assess how those factors were generally reported in studies on infants up to 2 years of age. To capture the latest findings in the field, we searched articles from PubMed 2012 onward with search terms referring to magnetic resonance imaging (MRI), brain development, and infancy. We identified 19 MRI studies focusing on the effects of prenatal environment and summarized them to highlight the recent advances in the field. We assessed population descriptions in a representative sample of 67 studies and conclude that prenatal factors that have been shown to affect brain metrics are not generally reported comprehensively. Based on our findings, we propose some improvements for population descriptions to account for plausible confounders and in time enable reliable meta-analyses to be performed. This could help the pediatric neuroimaging field move toward more reliable identification of biomarkers for developmental outcomes and to better decipher the nuances of normal and abnormal brain development.

Educational Disabilities Among Children Born With Neonatal Abstinence Syndrome

BACKGROUND

Neonatal abstinence syndrome (NAS) is a postnatal drug withdrawal syndrome that can occur after intrauterine opioid exposure. Adverse neurobehavioral outcomes have been documented in infants with NAS; however, educational outcomes have not been thoroughly examined. We analyzed Tennessee data to understand the need for special educational services among infants who are born with NAS.

METHODS

By using Tennessee Medicaid and birth certificate data, infants who were born in Tennessee between 2008 and 2011 with a history of NAS were matched (1:3) to infants who were born during the same period without a history of NAS. Groups were matched on the basis of sex, race and/or ethnicity, age, birth region of residence, and Medicaid enrollment status. Data were linked to Tennessee Department of Education special education data during early childhood (3-8 years of age). Conditional multivariable logistic regression was used to assess associations between NAS and selected special education outcomes.

RESULTS

A total of 1815 children with a history of NAS and 5441 children without NAS were assessed. Children with NAS were significantly more likely to be referred for a disability evaluation (351 of 1815 [19.3%] vs 745 of 5441 [13.7%]; P < .0001), to meet criteria for a disability (284 of 1815 [15.6%] vs 634 of 5441 [11.7%]; P < .0001), and to require classroom therapies or services (278 of 1815 [15.3%] vs 620 of 5441 [11.4%]; P < .0001). These findings were sustained in a multivariable analysis, with multiple models controlling for maternal tobacco use, maternal education status, birth weight, gestational age, and/or NICU admission.

CONCLUSIONS

Results of this novel analysis linking health and education data revealed that children with a history of NAS were significantly more likely to have a subsequent educational disability.

Neuroanatomical characteristics of youths with prenatal opioid and poly-drug exposure

Neuroanatomical and cognitive differences have been documented during childhood between children with prenatal opioid- and poly-drug exposure and controls in small samples. We investigated whether these differences persisted in larger samples of youth at older ages. Quantitative MRI and cognitive data were compared between 38 youths in the risk group and 44 youths in the non-exposed group (aged 17 to 22 years) who had been followed prospectively since birth. Most drug-exposed youths (84%) moved to permanent foster or adoptive homes before one year of age. The drug-exposed group displayed smaller neuroanatomical volumes (0.70 SD difference in total brain volume, p = 0.001), smaller cortical surface areas and thinner cortices than the comparison group. The birth weight accounted for some of the intergroup differences. Neuroanatomical characteristics partially mediated group differences in cognitive function. The present study cannot differentiate between causal factors but indicates persistent neurocognitive differences associated with prenatal opioid or poly-drug exposure.