Growth and developmental outcome of infants with in-utero exposure to methadone vs buprenorphine

A protocol for enhancing the diagnostic accuracy and predictive validity of neonatal opioid withdrawal syndrome: The utility of non-invasive clinical markers

Every 15 minutes in the US, an infant exposed to opioids is born. Approximately 50% of these newborns will develop Neonatal Opioid Withdrawal Syndrome (NOWS) within 5 days of birth. It is not known which infants will develop NOWS, therefore, the current hospital standard-of-care dictates a 96-hour observational hold. Understanding which infants will develop NOWS soon after birth could reduce hospital stays for infants who do not develop NOWS and decrease burdens on hospitals and clinicians. We propose noninvasive clinical indicators of NOWS, including newborn neurobehavior, autonomic biomarkers, prenatal substance exposures, and socioeconomic environments. The goals of this protocol are to use these indicators shortly after birth to differentiate newborns who will be diagnosed with NOWS from those who will have mild/no withdrawal, to determine if the indicators predict development at 6 and 18 months of age, and to increase NOWS diagnostic sensitivity for earlier, more accurate diagnoses.

Effects of prenatal exposure to methadone or buprenorphine and maternal separation on anxiety-like behavior in rats

BACKGROUND

The use of medications for opioid use disorder such as methadone or buprenorphine is increasing among pregnant women. However, long-term effects of this treatment on the children's health are not well understood. A key challenge is distinguishing the effects of opioid exposure from other confounding factors associated with human opioid use, such as reduced maternal care. In this study, we therefore used a multi-risk factor design to examine anxiety-like behavior in rats prenatally exposed to methadone or buprenorphine, with or without maternal separation the first two weeks after birth.

METHODS

Female Sprague Dawley rats were exposed to methadone (10mg/kg/day), buprenorphine (1mg/kg/day) or sterile water throughout gestation. Half of the offspring in each litter experienced maternal separation for 3h per day from postnatal day 2 to 12. Male and female offspring (6-9 weeks) were tested in the open field, light-dark transition and elevated plus maze tests to assess anxiety-like behavior.

RESULTS

Offspring exposed to buprenorphine and not subjected to maternal separation displayed increased anxiety-like behavior in 3 out of 6 outcomes in the light-dark transition and elevated plus maze tests. Maternal separation did not exacerbate, but rather diminished this behavior. Males and females responded differently to methadone, with a trend towards reduced anxiety for males and increased anxiety for females.

CONCLUSIONS

Prenatal exposure to methadone or buprenorphine may increase the risk of developing anxiety-like behavior later in life, but the effect depends on specific subgroup characteristics. Further research is required to draw definitive conclusions.

Intrauterine exposure to maternal opioid maintenance treatment and associated risk factors may impair child growth

AIM

How maternal opioid maintenance treatment (OMT) affects children is under-researched. This population-based registry study investigated child growth and somatic health following intrauterine exposure to this treatment.

METHODS

Children born between 1 March 2011 and 30 May 2021 to mothers who used buprenorphine, buprenorphine-naloxone, or methadone throughout their pregnancies were followed for 2 years at the Helsinki University Hospital, Finland. Appropriate statistical tests were used to compare the treatment groups.

RESULTS

Of the 67 neonates, 52% were male, 96% were born full-term and 63% were treated for neonatal opioid withdrawal syndrome. Otherwise, the children were predominantly healthy, although relatively small: 22% were small for gestational age, the methadone group children being the smallest. Foetal exposure to maternal methadone treatment, illicit drugs, hepatitis C and smoking were associated with small for gestational age; the former two were also associated with later slower growth, especially head growth and weight gain (p < 0.001). However, 29% were overweight at 2 years.

CONCLUSION

Using child growth as the outcome, we found that buprenorphine-naloxone and buprenorphine-monotherapy had equal effects as forms of maternal OMT. Exposure to multiple risk factors may harm foetal and subsequent growth. We recommend long-term follow-up of children exposed to maternal OMT.

Developmental Outcomes after Opioid Exposure in the Fetus and Neonate

The overall prevalence of opiate use has been increasing, currently affecting approximately 0.6% of the global population and resulting in a significant proportion of infants being born with prenatal opioid exposure. Animal and human models of prenatal opioid exposure demonstrate detrimental effects on brain anatomy as well as neurodevelopment. Less is known about the neurologic sequelae of postnatal opioid exposure in hospitalized infants. In this review, we summarize our current understanding of the impact of prenatal and postnatal opioid exposure on the brain and on neurodevelopment outcomes. We also identify resources and management strategies that may help mitigate neurodevelopmental delays and deficits associated with opioid exposure in this vulnerable population.

Investigating the neurobiology of maternal opioid use disorder and prenatal opioid exposure using brain organoid technology

Over the past two decades, Opioid Use Disorder (OUD) among pregnant women has become a major global public health concern. OUD has been characterized as a problematic pattern of opioid use despite adverse physical, psychological, behavioral, and or social consequences. Due to the relapsing-remitting nature of this disorder, pregnant mothers are chronically exposed to exogenous opioids, resulting in adverse neurological and neuropsychiatric outcomes. Collateral fetal exposure to opioids also precipitates severe neurodevelopmental and neurocognitive sequelae. At present, much of what is known regarding the neurobiological consequences of OUD and prenatal opioid exposure (POE) has been derived from preclinical studies in animal models and postnatal or postmortem investigations in humans. However, species-specific differences in brain development, variations in subject age/health/background, and disparities in sample collection or storage have complicated the interpretation of findings produced by these explorations. The ethical or logistical inaccessibility of human fetal brain tissue has also limited direct examinations of prenatal drug effects. To circumvent these confounding factors, recent groups have begun employing induced pluripotent stem cell (iPSC)-derived brain organoid technology, which provides access to key aspects of cellular and molecular brain development, structure, and function in vitro. In this review, we endeavor to encapsulate the advancements in brain organoid culture that have enabled scientists to model and dissect the neural underpinnings and effects of OUD and POE. We hope not only to emphasize the utility of brain organoids for investigating these conditions, but also to highlight opportunities for further technical and conceptual progress. Although the application of brain organoids to this critical field of research is still in its nascent stages, understanding the neurobiology of OUD and POE via this modality will provide critical insights for improving maternal and fetal outcomes.

A Prospective Multi-Institutional Study Comparing the Brain Development in the Third Trimester between Opioid-Exposed and Nonexposed Fetuses Using Advanced Fetal MR Imaging Techniques

BACKGROUND AND PURPOSE

While the adverse neurodevelopmental effects of prenatal opioid exposure on infants and children in the United States are well described, the underlying causative mechanisms have yet to be fully understood. This study aims to compare quantitative volumetric and surface-based features of the fetal brain between opioid-exposed fetuses and unexposed controls by using advanced MR imaging processing techniques.

MATERIALS AND METHODS

This is a multi-institutional IRB-approved study in which pregnant women with and without opioid use during the current pregnancy were prospectively recruited to undergo fetal MR imaging. A total of 14 opioid-exposed (31.4 ± 2.3 weeks of gestation) and 15 unexposed (31.4 ± 2.4 weeks) fetuses were included. Whole brain volume, cortical plate volume, surface area, sulcal depth, mean curvature, and gyrification index were computed as quantitative features by using our fetal brain MR imaging processing pipeline.

RESULTS

After correcting for gestational age, fetal sex, maternal education, polysubstance use, high blood pressure, and MR imaging acquisition site, all of the global morphologic features were significantly lower in the opioid-exposed fetuses compared with the unexposed fetuses, including brain volume, cortical volume, cortical surface area, sulcal depth, cortical mean curvature, and gyrification index. In regional analysis, the opioid-exposed fetuses showed significantly decreased surface area and sulcal depth in the bilateral Sylvian fissures, central sulci, parieto-occipital fissures, temporal cortices, and frontal cortices.

CONCLUSIONS

In this small cohort, prenatal opioid exposure was associated with altered fetal brain development in the third trimester. This adds to the growing body of literature demonstrating that prenatal opioid exposure affects the developing brain.

Methadone administered to rat dams during pregnancy and lactation affects the circadian rhythms of their pups

The circadian clock is one of the most important homeostatic systems regulating the majority of physiological functions. Its proper development contributes significantly to the maintenance of health in adulthood. Methadone is recommended for the treatment of opioid use disorders during pregnancy, increasing the number of children prenatally exposed to long-acting opioids. Although early-life opioid exposure has been studied for a number of behavioral and physiological changes observed later in life, information on the relationship between the effects of methadone exposure and circadian system development is lacking. Using a rat model, we investigated the effects of prenatal and early postnatal methadone administration on the maturation of the circadian clockwork in the suprachiasmatic nucleus (SCN) and liver, the rhythm of aralkylamine N-acetyltransferase (AA-NAT) activity in the pineal gland, and gene expression in the livers of 20-day-old rats. Our data show that repeated administration of methadone to pregnant and lactating mothers has significant effect on rhythmic gene expression in the SCN and livers and on the rhythm of AA-NAT in the offspring. Similar to previous studies with morphine, the rhythm amplitudes of the clock genes in the SCN and liver were unchanged or enhanced. However, six of seven specific genes in the liver showed significant downregulation of their expression, compared to the controls in at least one experimental group. Importantly, the amplitude of the AA-NAT rhythm was significantly reduced in all methadone-treated groups. As there is a strong correlation with melatonin levels, this result could be of importance for clinical practice.

Methadone alters transcriptional programs associated with synapse formation in human cortical organoids

Opioid use disorder (OUD) among pregnant women has become an epidemic in the United States. Pharmacological interventions for maternal OUD most commonly involve methadone, a synthetic opioid analgesic that attenuates withdrawal symptoms and behaviors linked with drug addiction. However, evidence of methadone's ability to readily accumulate in neural tissue, and cause long-term neurocognitive sequelae, has led to concerns regarding its effect on prenatal brain development. We utilized human cortical organoid (hCO) technology to probe how this drug impacts the earliest mechanisms of cortico-genesis. Bulk mRNA sequencing of 2-month-old hCOs chronically treated with a clinically relevant dose of 1 μM methadone for 50 days revealed a robust transcriptional response to methadone associated with functional components of the synapse, the underlying extracellular matrix (ECM), and cilia. Co-expression network and predictive protein-protein interaction analyses demonstrated that these changes occurred in concert, centered around a regulatory axis of growth factors, developmental signaling pathways, and matricellular proteins (MCPs). TGFβ1 was identified as an upstream regulator of this network and appeared as part of a highly interconnected cluster of MCPs, of which thrombospondin 1 (TSP1) was most prominently downregulated and exhibited dose-dependent reductions in protein levels. These results demonstrate that methadone exposure during early cortical development alters transcriptional programs associated with synaptogenesis, and that these changes arise by functionally modulating extra-synaptic molecular mechanisms in the ECM and cilia. Our findings provide novel insight into the molecular underpinnings of methadone's putative effect on cognitive and behavioral development and a basis for improving interventions for maternal opioid addiction.

Neonatal Opioid Withdrawal Syndrome: An Update on Developmental Outcomes

Infants and children with prenatal opioid exposure generally have development within the normal range; however, they seem to be at risk for behavioral problems and for lower scores on cognitive, language, and motor assessments than children without prenatal opioid exposure. It is as of yet unclear whether prenatal opioid exposure itself causes issues with development and behavior, or whether it is simply correlated, due to other confounding factors.

Buprenorphine Compared with Methadone in Pregnancy: A Systematic Review and Meta-Analysis

INTRODUCTION

Illicit opioid use in pregnancy is associated with adverse maternal, neonatal, and childhood outcomes. Opioid substitution is recommended, but whether methadone or buprenorphine is the optimal agent remains unclear.

METHODS

We searched EMBASE, PubMed, Web of Science, Scopus, Open Gray, CINAHL and the Cochrane Central Registry of Controlled Trials (CENTRAL) from inception to April 2020 for randomized controlled trials (RCTs) and cohort studies comparing methadone and buprenorphine treatment for opioid-using mothers. Included studies assessed maternal and or neonatal outcomes. We used random-effects meta-analyses to estimate summary measures for outcomes and report these separately for RCTs and cohort studies.

RESULTS

Of 408 abstracts screened, 20 papers were included (4 RCTs, 16 cohort, 223 and 7028 participants respectively). All RCTs (4/4) had a high risk of bias and median (IQR) Newcastle Ottawa Scale for cohort studies was 7.5 (6-9). In both RCTs and cohort studies, buprenorphine was associated with; greater offspring birth weight (weighted mean difference [WMD] 343 g (95% CI: 40-645 g) in RCT and 184 g (95% CI: 121-247 g) in cohort studies); body length at birth (WMD 2.28 cm (95% CI: 1.06-3.49 cm) in RCTs and 0.65 cm (95% CI: 0.31-0.98 cm) in cohort studies); and reduced risk of prematurity (risk ratio [RR] 0.41 (95% CI: 0.18-0.93) in RCTs and 0.63 [95% CI: 0.53-0.75] in cohort studies) when compared to methadone. All other clinical outcomes were comparable.

CONCLUSIONS

Compared to methadone, buprenorphine was consistently associated with improved birthweight and gestational age, however given potential biases, results should be interpreted with caution.

Head Circumference within the Normal Range and Neurodevelopmental Outcomes in Preterm Infants

OBJECTIVE

We sought to determine if variation in head circumference (HC) within the range of normal (5th-10th and 90th-95th percentile) is associated with poor neurodevelopmental outcomes (NDO), which defined as mild or moderate delay by Bayley II psychometrics (BSID-II).

STUDY DESIGN

This is a secondary analysis of a randomized controlled trial assessing the benefits of magnesium for the prevention of cerebral palsy. Fetuses with a normal HC at birth defined as within 5th to 95th percentile were included. NDO were assessed at age 2 with BSID-II. Moderate delay was defined as a score <70 and mild delay as <85. HC was classified as small normal (5th-10th percentile), normal (10th-90th percentile), and large normal (90th-95th percentile). Logistic regression models adjusted for confounding. Linear regression models estimated the impact for every 1 cm of change in HC.

RESULTS

Of 1,236 included infants, 111 (8%) had small normal HC; 1,058 (85%) had normal HC; and 67 (5%) had large normal HC. Baseline characteristics were similar between groups. There was no association with changes in HC within the range of normal and developmental indices. When considered as a continuous variable, every 1 cm increase in HC was also not associated with a significant change in developmental indices.

CONCLUSION

Within the normal range (5th-95th percentile), changes in HC did not correlate with changes in NDO at 2 years as measured by Bayley II scales.

KEY POINTS

· It is unknown if variations in normal HC are associated with poor neurodevelopmental outcomes.. · Alterations in HC within the range of normal (5th-95th percentile) are not associated with adverse NDO.. · When considered as a continuous variable, a 1 cm increase in HC is not associated with adverse NDO.. · Changes in HC within the range of normal do not appear to be a pathologic change altering NDO..

Prenatal methadone exposure and child developmental outcomes in 2-year-old children

AIM

To examine the developmental outcomes of children born to opioid-dependent females enrolled in methadone maintenance and identify pre- and postnatal factors that place these children at developmental risk.

METHOD

Ninety-nine methadone-maintained females and their 100 infants (42 females, 58 males, mean gestational age 38.8wks) were recruited during pregnancy/at birth and studied to age 2 years alongside a regionally representative comparison group of 108 non-methadone-maintained females and their 110 infants (62 females, 48 males, mean gestational age 39.2wks). Information about perinatal exposure was collected from medical records, maternal urine and infant meconium toxicological analysis, maternal interviews (at birth and at 18mo), and a home visit (at 18mo). At age 2 years, child neuromotor function, cognition, language, and emotional/behavioral dysregulation were assessed.

RESULTS

Opioid-exposed children achieved lower motor, cognitive, and language scores and had poorer self, emotional, eating/feeding, and sensory processing regulation than unexposed children. After adjustment for maternal education and other substance use in pregnancy, between-group differences in child motor, cognitive, and overall dysregulation remained. Postnatal parental and family factors explained a further 40% to 52% of between-group differences in child outcomes.

INTERPRETATION

These children and families are extremely high-risk and need antenatal and postnatal support. Children exposed to opioids during pregnancy have pervasive developmental difficulties by age 2 years. These challenges are largely explained by adverse pregnancy and socio-environmental exposures, emphasizing the importance of specialist prenatal care and postnatal intervention support. What this paper adds Children born to opioid-dependent females are at high risk of pervasive developmental problems. These problems span a range of functional domains, including motor, cognitive, language, and behavioral/emotional dysregulation. Contributing factors include other adverse pregnancy exposures, postnatal environmental factors, and the direct effects of prenatal opioid exposure.

Precision dosing of methadone during pregnancy: A pharmacokinetics virtual clinical trials study

BACKGROUND

Methadone use for the management of opioid dependency during pregnancy is commonplace. Methadone levels are altered during pregnancy due to changes in maternal physiology. Despite this, a paucity of data exist regarding the most appropriate optimal dosing regimens during pregnancy.

METHODS

This study applied a pharmacokinetic modeling approach to examine gestational changes in R- and S-methadone concentrations in maternal plasma and fetal (cord) blood. This study did so to derive a theoretical optimal dosing regimen during pregnancy, and to identify the impact of Cytochromes P450 (CYP) 2B6 and 2C19 polymorphisms on methadone maternal and fetal pharmacokinetics.

RESULTS

The study noted significant decreases in maternal R- and S-methadone plasma concentrations during gestation, with concomitant increases in fetal levels. At a dose of 90 mg once daily, 75% (R-) and 94% (S-) of maternal methadone trough levels were below the lower therapeutic window at term (week 40). The developed optimal dosing regimen escalated doses to 110 mg by week 5, followed by 10 mg increments every 5 weeks up to a maximum of 180 mg once daily near term. This increase resulted in 27% (R-) and 11% (S-) of subjects with trough levels below the lower therapeutic window at term. CYP2B6 poor metabolizers (PM) and either CYP2C19 extensive metabolizers (EM), PM, or ultra-rapid (UM) metabolizer phenotypes demonstrated statistically significant increases in concentrations when compared to their matched CYP2B6 EM counterparts.

CONCLUSIONS

Specific and gestation-dependent dose titrations are required during pregnancy to reduce the risks associated with illicit drug use and to maintain fetal safety.

Using buprenorphine to treat neonatal abstinence syndrome: a quality improvement study

OBJECTIVE

To assess if treating neonatal abstinence syndrome (NAS) with sublingual buprenorphine (SLB) would decrease the mean duration of therapy (DOT) and length of birth hospital stay (LOS).

STUDY DESIGN

Conducted at a tertiary hospital with >6000 annual deliveries and a 2% incidence of NAS, a quality improvement study using plan-do-study-act (PDSA) cycles were utilized. Outcomes were measured using statistical process control (SPC) charts.

RESULTS

All NAS patients were treated with SLB, no adverse reactions were reported and the need for an adjunctive agent was static. SPC charts demonstrated decreased variability and special cause variation indicating a reduction in both DOT (from 14.5 to 8.5 days) and LOS (from 18.5 to 13 days).

Neuroimaging in infants with prenatal opioid exposure: Current evidence, recent developments and targets for future research

Prenatal opioid exposure (POE) has shown to be a risk factor for adverse long-term cognitive and behavioral outcomes in offspring. However, the neural mechanisms of these outcomes remain poorly understood. While preclinical and human studies suggest that these outcomes may be due to opioid-mediated changes in the fetal and early postnatal brain, other maternal, social, and environmental factors are also shown to play a role. Recent neuroimaging studies reveal brain alterations in children with POE. Early neuroimaging and novel methodology could provide an in vivo mechanistic understanding of opioid mediated alterations in developing brain. However, this is an area of ongoing research. In this review we explore recent imaging developments in POE, with emphasis on the neonatal and infant brain, and highlight some of the challenges of imaging the developing brain in this population. We also highlight evidence from animal models and imaging in older children and youth to understand areas where future research may be targeted in infants with POE.

Association of Maternal Buprenorphine or Methadone Dose with Fetal Growth Indices and Neonatal Abstinence Syndrome

OBJECTIVE

Our objective was to compare fetal growth and incidence of neonatal abstinence syndrome requiring treatment across pregnant women with opioid use disorders on two types and two dose categories of medication-assisted treatment.

STUDY DESIGN

A retrospective cohort study was conducted in a comprehensive, perinatal program in western North Carolina comparing growth percentiles on third-trimester ultrasound and at birth, and diagnosis of neonatal abstinence syndrome requiring treatment. Singletons were exposed in utero to low- to moderate-dose buprenorphine (≤16 mg/day; n = 70), high-dose buprenorphine (≥17 mg/day; n = 36), low- to moderate-dose methadone (≤89 mg/day; n = 41), or high-dose methadone (≥90 mg/day; n = 74). Multivariate analysis of variance with posthoc Bonferroni comparisons (p ≤ 0.01) and multinomial logistic regressions (adjusted odds ratio, 99% confidence interval) were conducted.

RESULTS

Differences in neonatal outcomes reached statistical significance for larger head circumference for buprenorphine doses (p = 0.01) and for longer length (p < 0.01) and lower odds of neonatal abstinence syndrome requiring treatment (p < 0.01) with low- to moderate-dose buprenorphine versus high-dose methadone.

CONCLUSION

Among pregnant women using medication-assisted treatment for opioid use disorders, low- to moderate-dose buprenorphine (≤16 mg/day) was associated with the most favorable neonatal outcomes. However, more rigorous control of confounders with a larger sample is necessary to determine if low- to moderate-dose buprenorphine is the better treatment choice.

Resting state functional MRI in infants with prenatal opioid exposure-a pilot study

PURPOSE

Exposure to prenatal opioids may adversely impact the developing brain networks. The aim of this pilot study was to evaluate alterations in amygdalar functional connectivity in human infants with prenatal opioid exposure.

METHODS

In this prospective IRB approved study, we performed resting state functional MRI (rs-fMRI) in 10 infants with prenatal opioid exposure and 12 infants without prenatal drug exposure at < 48 weeks corrected gestational age. Following standard preprocessing, we performed seed-based functional connectivity analysis with the right and left amygdala as the regions of interest after correcting for maternal depression and infant sex. We compared functional connectivity of the amygdala network between infants with and without prenatal opioid exposure.

RESULTS

There were significant differences in connectivity of the amygdala seed regions to the several cortical regions including the medial prefrontal cortex in infants who had prenatal opioid exposure when compared with opioid naïve infants.

CONCLUSION

This finding of increased amygdala functional connectivity in infants with in utero opioid exposure suggests a potential role of maternal opioid exposure on infants' altered amygdala function. This association with prenatal exposure needs to be replicated in future larger studies.

Prenatal exposure to methadone or buprenorphine impairs cognitive performance in young adult rats

BACKGROUND

Concerns have been raised about the use of opioid maintenance treatment (OMT) during pregnancy and negative effects for the offspring. While neonatal outcomes and short-term effects are relatively well described, studies examining long-term effects in adolescents and adults are absent. The aim of the present study was to examine effects on learning and memory in young adult rats prenatally exposed to methadone or buprenorphine.

METHODS

Female rats were implanted with a 28-day osmotic minipump delivering methadone (10 mg/kg/day), buprenorphine (1 mg/kg/day) or vehicle 5 days prior to mating. To examine possible effects on cognitive functioning, young adult offspring were included in three different behavioral tests that examine recognition memory, nonspatial, and spatial learning and memory. In addition, offspring growth and maternal behavior after birh were investigated.

RESULTS

Prenatal exposure to methadone or buprenorphine caused impaired recognition memory and nonspatial reference learning and memory in young adult rats compared with the vehicle-treated group. Methadone-exposed offspring, but not the buprenorphine-exposed, also showed reduced long-term spatial memory. We did not observe any changes in maternal behavior or offspring growth after prenatal exposure to methadone or buprenorphine, suggesting that the impaired cognitive functioning is due to the opioid exposure rather than reduced maternal caregiving.

CONCLUSION

The present findings of long-term cognitive impairments in methadone- and buprenorphine-exposed offspring points to a negative impact of OMT on neurobiological development.

The impact of neuropsychiatric disease on fetal growth: a case-control study

PURPOSE

To determine the impact of depression, epilepsy and drug abuse during pregnancy on delivery and fetal outcome. Due to the worldwide increasing prevalence of neurological and psychiatric diseases and drug abuse, the number of affected pregnant women is increasing.

METHODS

A large-scale retrospective case-control analysis of pregnancies affected by depression, epilepsy or drug abuse with and without medication was conducted in two German perinatal centres between 2013 and 2017. The case group consisted of 706 pregnant women who had a diagnosis of depression, epilepsy or drug abuse vs. 12,574 pregnant women without neuropsychiatric diagnosis (control group). The analysis included the rate of intrauterine growth restriction, birth weight and length, neonatal head circumference.

RESULTS

Significant differences in the subgroups were found in the parameters intrauterine growth restriction, birth weight, length and head circumference. Women with epilepsy were affected less often than women with depression and substance abuse. Major differences were found in the group of women with substance abuse. Negative associations were found within the non-pharmacologically managed disease group itself compared to women exposed to medication.

CONCLUSION

The present results demonstrated a negative association between maternal neurological or psychiatric disease and pregnancy outcome in the examined parameters. However, the non-pharmacologically treated maternal disease was identified as a risk factor itself.

High Accumulation of Methadone Compared with Buprenorphine in Fetal Rat Brain after Maternal Exposure

Experimental animal studies are valuable in revealing a causal relationship between prenatal exposure to opioid maintenance treatment (OMT) and subsequent effects; however, previous animal studies of OMT during pregnancy have been criticized for their lack of clinical relevance because of their use of high drug doses and the absence of pharmacokinetic data. Hence, the aim of this study was to determine blood and brain concentrations in rat dams, fetuses, and offspring after continuous maternal exposure to methadone or buprenorphine during gestation and to examine the offspring for neonatal outcomes and withdrawal symptoms. Female rats were implanted with a 28-day osmotic minipump delivering methadone (10 mg/kg per day), buprenorphine (1 mg/kg per day) or vehicle 5 days before mating. Continuous exposure to methadone or buprenorphine induced stable blood concentrations in the dams of 0.25 ± 0.02 µM and 5.65 ± 0.16 nM, respectively. The fetal brain concentration of methadone (1.89 ± 0.35 nmol/g) was twice as high as that in the maternal brain, whereas the fetal brain concentration of buprenorphine (20.02 ± 4.97 pmol/g) was one-third the maternal brain concentration. The opioids remained in the offspring brain several days after the exposure ceased. Offspring prenatally exposed to methadone, but not buprenorphine, displayed reduced body weight and length and increased corticosterone levels. No significant changes in ultrasonic vocalizations were revealed. Our data in rat fetuses and neonates indicate that OMT with buprenorphine may be a better choice than methadone during pregnancy. SIGNIFICANCE STATEMENT: Concern has been raised about the use of opioid maintenance treatment during pregnancy because of the important role of the endogenous opioid system in brain development. Here, we show that the methadone concentration in the fetal rat brain was twice as high as that in the maternal brain, whereas the buprenorphine concentration was one-third the maternal concentration. Furthermore, buprenorphine allowed more favorable birth outcomes, suggesting that buprenorphine may be a better choice during pregnancy.

Prenatal Opioid Exposure: Neurodevelopmental Consequences and Future Research Priorities

Neonatal opioid withdrawal syndrome (NOWS) has risen in prevalence from 1.2 per 1000 births in 2000 to 5.8 per 1000 births in 2012. Symptoms in neonates may include high-pitched cry, tremors, feeding difficulty, hypertonia, watery stools, and breathing problems. However, little is known about the neurodevelopmental consequences of prenatal opioid exposure in infancy, early childhood, and middle childhood. Even less is known about the cognitive, behavioral, and academic outcomes of children who develop NOWS. We review the state of the literature on the neurodevelopmental consequences of prenatal opioid exposure with a particular focus on studies in which NOWS outcomes were examined. Aiming to reduce the incidence of prenatal opioid exposure in the near future, we highlight the need for large studies with prospectively recruited participants and longitudinal designs, taking into account confounding factors such as socioeconomic status, institutional variations in care, and maternal use of other substances, to independently assess the full impact of NOWS. As a more immediate solution, we provide an agenda for future research that leverages the National Institutes of Health Environmental Influences on Child Health Outcomes program to address many of the serious methodologic gaps in the literature, and we answer key questions regarding the short- and long-term neurodevelopmental health of children with prenatal opioid exposure.

Childhood neurodevelopment after prescription of maintenance methadone for opioid dependency in pregnancy: a systematic review and meta-analysis

AIM

To systematically review and meta-analyse studies of neurodevelopmental outcome of children born to mothers prescribed methadone in pregnancy.

METHOD

MEDLINE, Embase, and PsycINFO were searched for studies published from 1975 to 2017 reporting neurodevelopmental outcomes in children with prenatal methadone exposure.

RESULTS

Forty-one studies were identified (2283 participants). Eight studies were amenable to meta-analysis: at 2 years the Mental Development Index weighted mean difference of children with prenatal methadone exposure compared with unexposed infants was -4.3 (95% confidence interval [CI] -7.24 to -1.63), and the Psychomotor Development Index weighted mean difference was -5.42 (95% CI -10.55 to -0.28). Seven studies reported behavioural scores and six found scores to be lower among methadone-exposed children. Twelve studies reported visual outcomes: nystagmus and strabismus were common; five studies reported visual evoked potentials of which four described abnormalities. Factors that limited the quality of some studies, and introduced risk of bias, included absence of blinding, small sample size, high attrition, uncertainty about polydrug exposure, and lack of comparison group validity.

INTERPRETATION

Children born to mothers prescribed methadone in pregnancy are at risk of neurodevelopmental problems but risk of bias limits inference about harm. Research into management of opioid use disorder in pregnancy should include evaluation of childhood neurodevelopmental outcome.

WHAT THIS PAPER ADDS

Children born to opioid-dependent mothers prescribed methadone are at risk of neurodevelopmental impairment. Exposed infants have lower Mental Development Index and Psychomotor Development Index scores than unexposed children. Atypical visual evoked potentials, strabismus, and nystagmus have increased prevalence. Estimates of impairment may be biased by intermediate to poor quality evidence.

"Choose Physical Therapy" for Neonatal Abstinence Syndrome: Clinical Management for Infants Affected by the Opioid Crisis

In response to the opioid crisis, the American Physical Therapy Association has strongly advocated for physical therapy as a safe alternative to pharmacological pain management through the "#ChoosePT" campaign and the dedication of a PTJ special issue to the nonpharmacological management of pain. Physical therapists not only play an important role in the rehabilitation of the nearly 2 million adolescents and adults addicted to prescription opioids but also provide care to infants born to mothers with various drug addictions. This Perspective article explores the incidence, pathophysiology, and risk factors for neonatal abstinence syndrome and describes the clinical presentations of withdrawal and neurotoxicity in infants. Discipline-specific recommendations for the physical therapist examination and plan of care, including pharmacological management considerations, are outlined. Nonpharmacological management, including supportive care, feeding, parent education, social aspects of care, and follow-up services, are discussed from a physical therapy perspective. Finally, this article reviews developmental outcomes in infants with neonatal abstinence syndrome and reflects on challenges and future directions of research in this area.

Implications of perinatal buprenorphine exposure on infant head circumference at birth

Objective: To determine the potential impact of prenatal buprenorphine exposure on head circumference at birth and analyze whether head circumference may be related to maternal buprenorphine dose at delivery, delayed maternal entry into buprenorphine treatment or exposure to a variety of other medications and substances.Methods: A retrospective cohort study was performed of 137 full-term infants exposed to buprenorphine during pregnancy from January 2013 to December 2017. Pearson's correlation was calculated to investigate the potential relationship between head circumference and maternal dose of buprenorphine at delivery. t-tests were conducted to analyze head circumference in relationship to dichotomous variables.Results: Head circumference in infants exposed to buprenorphine during pregnancy was not significantly different from national norms for either male infants (95% CI 28.2-33.5 cm, norm 31.5 cm, and 28.5-34.9 cm, norm 33.1 cm, for the 3rd and 10th percentile, respectively) or female infants (95% CI 28.7-32.8 cm, norm 31.9 cm, and 29.1-34.3, norm 32.8 cm for the 3rd and 10th percentile, respectively). Head circumference was not associated with delayed maternal entry into buprenorphine treatment (t = -1.0715, p = .287) or exposure to psychotropic medications during pregnancy (t = 0.4194, p = .677). There was no relationship between infant head circumference and maternal buprenorphine dose at delivery (r = 0.004, p = .967). Head circumference was not associated with maternal smoking (t = 0.003, p = .998) or exposure to marijuana (t = 0.7277, p = .468), illicit opioids (t = -0.6701, p = .504), illicit amphetamines (t = -0.4062, p = .687) or illicit benzodiazepines (t = -0.6288, p = .535) during pregnancy.Conclusions: Exposure to buprenorphine prenatally does not appear to be associated with reduced head circumference at birth. Head circumference at birth also does not appear related to either maternal buprenorphine dose at delivery or delayed entry into treatment. As previous literature suggests that high dose methadone exposure during pregnancy may be associated with smaller head circumference and that smaller head circumference may be associated with risk of neurocognitive disorders, our results further support the use of buprenorphine as a first line treatment for opioid use disorders during pregnancy.

Association between prenatal opioid exposure, neonatal opioid withdrawal syndrome, and neurodevelopmental and behavioral outcomes at 5-8 months of age

BACKGROUND

While use of prescription opioids and medication assisted therapy (MAT) for opioid use disorder in pregnancy, as well as the incidence of neonatal opioid withdrawal syndrome (NOWS) continue to rise, little is known about outcomes for children with NOWS beyond the newborn period.

METHODS

We examined 1) prenatal MAT exposure vs. unexposed healthy controls [HC]; and 2) treatment for NOWS and NOWS severity on infant neurodevelopmental and behavioral outcomes at 5-8 months of age in 78 maternal-infant pairs from the ENRICH prospective cohort study. Data were obtained from 3 study visits: prenatal, delivery, and neurodevelopmental evaluation at 5-8 months of age. Neurodevelopmental outcomes included the Bayley Scales of Infant Development [BSID-III], caregiver questionnaires (Parenting Stress Index [PSI-SF], Infant Behavior Questionnaire [IBQ-R], Sensory Profile), and the experimental Still-Face Paradigm (SFP).

RESULTS

No differences in the BSID-III, PSI-SF, or IBQ-R scores were observed between MAT and HC groups; however, MAT-exposed and HC infants differed with respect to SFP self-regulation (β = -18.9; p = 0.01) and Sensory Profile sensation seeking (OR = 4.87; 95% CI: 1.55; 15.30) after adjusting for covariates. No significant differences between Treated-for-NOWS vs. not-Treated-for-NOWS were observed. Shorter timing to NOWS treatment initiation was associated with higher Total Stress (β = -9.08; p = 0.035), while longer hospitalization was associated with higher Parent-child dysfunctional interaction (p = 0.018) on PSI-SF.

CONCLUSIONS

Our results provide additional evidence of little-to-no effect of MAT and pharmacological treatment of NOWS on infant neurodevelopmental and behavioral outcomes at 5-8 months of age. However, prolonged hospitalization might increase family psychosocial stress and requires further examination.

Psychological Functioning of Women Taking Illicit Drugs during Pregnancy and the Growth and Development of Their Offspring in Early Childhood

OBJECTIVE

The aim of this research was to assess psychosocial history and psychological functioning in women who use drugs during pregnancy and determine how drug exposure affects child development.

METHODS

Pregnant women using marijuana (n = 38) and cocaine (n = 35) and receiving methadone maintenance (n = 24), along with a control (n = 49) group of pregnant women, were enrolled and followed every six months through 18-24 months postnatally.

RESULTS

There was a significantly higher incidence of mental illness among mothers in the drug-using groups. Prenatal stress and late-term drug severity scores were significantly higher in the mothers who used cocaine and methadone, who were also more likely to have abuse and incarceration histories. At 12 months, there were significantly higher rates of drug use in the marijuana group. Anxiety scores were highest in the methadone group. At 18 to 24 months, the methadone group reported significantly more stress, and methadone and marijuana groups had significantly higher anxiety and depression scores. At birth, neonates from the methadone and marijuana groups had significantly smaller head circumferences, with the smallest values in the methadone group. At one year, children in the cocaine group had significantly lower Bayley Scales of Infant Development-Third Edition (Bayley-III) cognitive and motor scores. At 18 to 24 months, children in the methadone group had significantly smaller head circumferences and Bayley-III cognitive scores. Children in the methadone and cocaine groups had a significantly higher incidence of atypical neurological examinations at 6 to 9 and 18 to 24 months.

CONCLUSIONS

Mothers in the methadone and cocaine groups presented with more severe prenatal drug use and psychosocial risk factors relative to women who used primarily marijuana. Children in the cocaine and methadone groups were neurologically atypical relative to others at study end. Mothers in the marijuana group reported chronic drug use as well as anxiety and depression at follow-up. At birth, children in the marijuana group were smaller, but this resolved with time. Similarly, children in the cocaine group had motor and cognitive delays that resolved by age two. Children in the methadone group had persistent growth and cognitive deficits. Their mothers demonstrated more anxiety, depression, and stress, the combination of which left these women and children liable to face ongoing psychosocial struggle and psychological distress. Dual interventions for mother and child should be considered in attempting to optimize outcome.

Prenatal exposure to methadone or buprenorphine: Early childhood developmental outcomes

BACKGROUND

Methadone and buprenorphine are recommended to treat opioid use disorders during pregnancy. However, the literature on the relationship between longer-term effects of prenatal exposure to these medications and childhood development is both spare and inconsistent.

METHODS

Participants were 96 children and their mothers who participated in MOTHER, a randomized controlled trial of opioid-agonist pharmacotherapy during pregnancy. The present study examined child growth parameters, cognition, language abilities, sensory processing, and temperament from 0 to 36 months of the child's life. Maternal perceptions of parenting stress, home environment, and addiction severity were also examined.

RESULTS

Tests of mean differences between children prenatally exposed to methadone vs. buprenorphine over the three-year period yielded 2/37 significant findings for children. Similarly, tests of mean differences between children treated for NAS relative to those not treated for NAS yielded 1/37 significant finding. Changes over time occurred for 27/37 child outcomes including expected child increases in weight, head and height, and overall gains in cognitive development, language abilities, sensory processing, and temperament. For mothers, significant changes over time in parenting stress (9/17 scales) suggested increasing difficulties with their children, notably seen in increasing parenting stress, but also an increasingly enriched home environment (4/7 scales) CONCLUSIONS: Findings strongly suggest no deleterious effects of buprenorphine relative to methadone or of treatment for NAS severity relative to not-treated for NAS on growth, cognitive development, language abilities, sensory processing, and temperament. Moreover, findings suggest that prenatal opioid agonist exposure is not deleterious to normal physical and mental development.

Opioid dependence and pregnancy: minimizing stress on the fetal brain

Increase in the number of opioid-dependent pregnant women delivering babies at risk for neonatal abstinence syndrome prompted a US Government Accountability Office report documenting deficits in research and provider knowledge about care of the maternal/fetal unit and the neonate. There are 3 general sources of dependence: untreated opioid use disorder, pain management, and medication-assisted treatment with methadone or buprenorphine. A survey of methadone patients' experiences when telling a physician of their pregnancy and opioid dependence demonstrated physician confusion about proper care, frequent negative interactions with the mother, and failures to provide appropriate referral. Patients in pain management were discharged without referral when the physician was told of the pregnancy. Methadone and buprenorphine were frequently seen negatively because they "caused" neonatal abstinence syndrome. Most mothers surveyed had to find opioid treatment on their own. How dependence is managed medically is a critical determinant of the level of stress on both mother and fetus, and therefore another determinant of neonatal health. The effects of both opioid withdrawal stress and maternal emotional stress on neonatal and developmental outcomes are reviewed. Currently, there have been efforts to criminalize maternal opioid dependence and to encourage or coerce pregnant women to undergo withdrawal. This practice poses both acute risks of fetal hypoxia and long-term risks of adverse epigenetic programming related to catecholamine and corticosteroid surges during withdrawal. Contemporary studies of the effects of withdrawal stress on the developing fetal brain are urgently needed to elucidate and quantify the risks of such practices. At birth, inconsistencies in the hospital management of neonates at risk for neonatal abstinence syndrome have been observed. Neglect of the critical role of maternal comforting in neonatal abstinence syndrome management is an iatrogenic and preventable cause of poor outcomes and long hospitalizations. Rooming-in allows for continuous care of the baby and maternal/neonatal attachment, often unwittingly disrupted by the neonatal intensive care unit environment. Recommendations are made for further research into physician/patient interactions and into optimal dosing of methadone and buprenorphine to minimize maternal/fetal withdrawal.