Fetal neurobehavioral effects of exposure to methadone or buprenorphine

Gestational buprenorphine-naloxone exposure and fetal neurobehavior

BACKGROUND

Buprenorphine-naloxone treatment may confer substantial benefits for the treatment of opioid use disorder (OUD) during pregnancy including lower risk for overdose/death, less diversion potential and reduced use of other substances. Treatment may also result in less severe Neonatal Abstinence Syndrome (NAS), but little is known about the effects of this medication on fetal neurodevelopment.

METHODS

The purpose of the current study is to evaluate neurobehaviors among fetuses exposed to buprenorphine-naloxone at four time points over the second and third trimesters of gestation in pregnant women with OUD on buprenorphine-naloxone therapy. Sixty minutes of continuous fetal monitoring via fetal actocardiograph with a single wide array abdominal transducer took place at times of peak and trough buprenorphine-naloxone levels in 24 pregnant women. Data collection, which included measures of fetal heart rate and motor activity, was conducted between 24 and 36 weeks gestation, with the majority (84.6%) monitored at two or more gestational ages. Medication dose and other substance use was monitored throughout the study and infant NAS severity was assessed.

RESULTS

Fetal heart rate (FHR), FHR variability, accelerations in FHR, and motor activity were suppressed when buprenorphine-naloxone levels were at pharmacologic peak as compared to trough concentrations at 36 weeks, but not earlier in gestation. Maternal medication dose was unrelated to infant NAS severity.

CONCLUSIONS

Conclusions: There were evident subclinical fetal neurophysiological responses at times of peak maternal buprenorphine/naloxone levels in later gestation, similar to those previously described for buprenorphine only. Further studies evaluating the effects of these changes in fetal neurobehaviors on the longer-term infant development are needed.

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, methamphetamine, and polysubstance use: perinatal outcomes for the mother and infant

The escalation in opioid pain relief (OPR) medications, heroin and fentanyl, has led to an increased use during pregnancy and a public health crisis. Methamphetamine use in women of childbearing age has now eclipsed the use of cocaine and other stimulants globally. Recent reports have shown increases in methamphetamine are selective to opioid use, particularly in rural regions in the US. This report compares the extent of our knowledge of the perinatal outcomes of OPRs, heroin, fentanyl, two long-acting substances used in the treatment of opioid use disorders (buprenorphine and methadone), and methamphetamine. The methodological limitations of the current research are examined, and two important initiatives that will address these limitations are reviewed. Current knowledge of the perinatal effects of short-acting opioids, OPRs, heroin, and fentanyl, is scarce. Most of what we know about the perinatal effects of opioids comes from research on the long-acting opioid agonist drugs used in the treatment of OUDs, methadone and buprenorphine. Both have better perinatal outcomes for the mother and newborn than heroin, but the uptake of these opioid substitution programs is poor (<50%). Current research on perinatal outcomes of methamphetamine is limited to retrospective epidemiological studies, chart reviews, one study from a treatment center in Hawaii, and the US and NZ cross-cultural infant Development, Environment And Lifestyle IDEAL studies. Characteristics of pregnant individuals in both opioid and MA studies were associated with poor maternal health, higher rates of mental illness, trauma, and poverty. Infant outcomes that differed between opioid and MA exposure included variations in neurobehavior at birth which could complicate the diagnosis and treatment of neonatal opioid withdrawal (NOWs). Given the complexity of OUDs in pregnant individuals and the increasing co-use of these opioids with MA, large studies are needed. These studies need to address the many confounders to perinatal outcomes and employ neurodevelopmental markers at birth that can help predict long-term neurodevelopmental outcomes. Two US initiatives that can provide critical research and treatment answers to this public health crisis are the US Environmental influences on Child Health Outcomes (ECHO) program and the Medication for Opioid Use Disorder During Pregnancy Network (MAT-LINK).

MRI Findings in Third-Trimester Opioid-Exposed Fetuses, With Focus on Brain Measurements: A Prospective Multicenter Case-Control Study

BACKGROUND. The opioid epidemic has profoundly affected infants born in the United States, as in utero opioid exposure increases the risk of cognitive and behavioral problems in childhood. Scarce literature has evaluated prenatal brain development in fetuses with opioid exposure in utero (hereafter opioid-exposed fetuses). OBJECTIVE. The purpose of this study is to compare opioid-exposed fetuses and fetuses without opioid exposure (hereafter unexposed fetuses) in terms of 2D biometric measurements of the brain and additional pregnancy-related assessments on fetal MRI. METHODS. This prospective case-control study included patients in the third trimester of pregnancy who underwent investigational fetal MRI at one of three U.S. academic medical centers from July 1, 2020, through December 31, 2021. Fetuses were classified as opioid exposed or unexposed in utero. Fourteen 2D biometric measurements of the fetal brain were manually assessed and used to derive four indexes. Measurements and indexes were compared between the two groups by use of multivariable linear regression models, which were adjusted for gestational age (GA), fetal sex, and nicotine exposure. Additional pregnancy-related findings on MRI were evaluated. RESULTS. The study included 65 women (mean age, 29.0 ± 5.5 [SD] years). A total of 28 fetuses (mean GA at the time of MRI, 32.2 ± 2.5 weeks) were opioid-exposed, and 37 fetuses (mean GA at the time of MRI, 31.9 ± 2.7 weeks) were unexposed. In the adjusted models, seven measurements were smaller (p < .05) in opioid-exposed fetuses than in unexposed fetuses: cerebral frontooccipital diameter (93.8 ± 7.4 vs 95.0 ± 8.6 mm), bone biparietal diameter (79.0 ± 6.0 vs 80.3 ± 7.1 mm), brain biparietal diameter (72.9 ± 7.7 vs 74.1 ± 8.6 mm), corpus callosum length (37.7 ± 4.0 vs 39.4 ± 3.7 mm), vermis height (18.2 ± 2.7 vs 18.8 ± 2.6 mm), anteroposterior pons measurement (11.6 ± 1.4 vs 12.1 ± 1.4 mm), and transverse cerebellar diameter (40.4 ± 5.1 vs 41.4 ± 6.0 mm). In addition, in the adjusted model, the frontoocccipital index was larger (p = .02) in opioid-exposed fetuses (0.04 ± 0.02) than in unexposed fetuses (0.04 ± 0.02). Remaining measures and indexes were not significantly different between the two groups (p > .05). Fetal motion, cervical length, and deepest vertical pocket of amniotic fluid were not significantly different (p > .05) between groups. Opioid-exposed fetuses, compared with unexposed fetuses, showed higher frequencies of both breech position (21% vs 3%, p = .03) and increased amniotic fluid volume (29% vs 8%, p = .04). CONCLUSION. Fetuses with opioid exposure in utero had a smaller brain size and altered fetal physiology. CLINICAL IMPACT. The findings provide insight into the impact of prenatal opioid exposure on fetal brain development.

Comparative Safety Analysis of Opioid Agonist Treatment in Pregnant Women with Opioid Use Disorder: A Population-Based Study

INTRODUCTION AND OBJECTIVE

Receipt of opioid agonist treatment during early and late pregnancy for opioid use disorder may relate to varying perinatal risks. We aimed to assess the effect of time-varying prenatal exposure to opioid agonist treatment using buprenorphine or methadone on adverse neonatal and pregnancy outcomes.

METHODS

We conducted a retrospective cohort study of pregnant women with opioid use disorder using Rhode Island Medicaid claims data and vital statistics during 2008-16. Time-varying exposure was evaluated in early (0-20 weeks) and late (≥ 21 weeks) pregnancy. Marginal structural models with inverse probability of treatment weighting were applied.

RESULTS

Of 400 eligible pregnancies, 85 and 137 individuals received buprenorphine and methadone, respectively, during early pregnancy. Compared with 152 untreated pregnancies with opioid use disorders, methadone exposure in both periods was associated with an increased risk of preterm birth (adjusted odds ratio [aOR]: 2.52; 95% confidence interval [CI] 1.07-5.95), low birth weight (aOR: 2.99; 95% CI 1.34-6.66), neonatal intensive care unit admission (aOR, 5.04; 95% CI 2.49-10.21), neonatal abstinence syndrome (aOR: 11.36; 95% CI 5.65-22.82), respiratory symptoms (aOR, 2.71; 95% CI 1.17-6.24), and maternal hospital stay > 7 days (aOR, 14.51; 95% CI 7.23-29.12). Similar patterns emerged for buprenorphine regarding neonatal abstinence syndrome (aOR: 10.27; 95% CI 4.91-21.47) and extended maternal hospital stay (aOR: 3.84; 95% CI 1.83-8.07). However, differences were found favoring the use of buprenorphine for preterm birth versus untreated pregnancies (aOR: 0.17; 95% CI 0.04-0.77), and for several outcomes versus methadone.

CONCLUSIONS

Methadone and buprenorphine prescribed for the treatment of opioid use disorder during pregnancy are associated with varying perinatal risks. However, buprenorphine may be preferred in the setting of pregnancy opioid agonist treatment. Further research is necessary to confirm our findings and minimize residual confounding.

Impact of prenatal opioids on cardiac and autonomic development: systematic review and meta-analysis

Prenatal opioid exposure has recently risen four-fold with limited data on the developmental effects on neonatal physiology. The objective of this systematic review is to develop an association between prenatal opioid exposure and fetal and neonatal cardiac and autonomic development and function. The review was conducted in accordance with PRISMA Guidelines, and searches were conducted using PubMed, Embase, CINAHL, and Web of Science between May 25 and October 27, 2020. Twenty studies fit inclusion criteria, in four categories: (1) fetal cardiac outcomes, (2) neonatal cardiac outcomes, (3) noninvasive autonomic outcomes, and (4) clinical and behavioral measures. For the meta-analysis, three studies (total of 210 subjects) were included. Effect sizes were measured as the mean difference in fetal heart rate between opioid-exposed and non-exposed groups. Mothers with prenatal opioid use had a significantly lower fetal heart rate as compared to mothers without prenatal opioid use, requiring further studies to determine clinical significance.

Opioids and the developing brain: time to rethink perinatal care for infants of opioid-dependent mothers

Illicit use of opioids is a global health crisis with major implications for women and children. Strategies for managing opioid use disorder (OUD) in pregnancy have been tested over the past 40 years, but studies have focused on maternal and pregnancy outcomes, with less attention given to long-term follow-up of exposed children. Here, we provide a narrative review of recent advances in the assessment and management of neonatal opioid withdrawal syndrome (NOWS), and we summarise evidence from multiple domains-neuroimaging, electrophysiology, visual development and function, neurodevelopment, behaviour, cognition and education-which suggests that prenatal opioid exposure modifies child development. Further studies are required to determine the optimal management of pregnant women with OUD and babies with NOWS. We identify knowledge gaps and suggest that future study designs should evaluate childhood outcomes, including infant brain development and long-term neurocognitive and visual function.

Oxidative Stress Indices Changes in the Hearts of Rat Pups in Response to Maternal Buprenorphine Treatment during Gestation and Lactation

This study aimed to assess the effects of Buprenorphine (BUP) on oxidative parameters in pups born to mothers exposed to the drug during gestation and lactation. Pregnant and lactating rats received BUP, 0.5 or 0.1 mg/kg subcutaneously for 21 and 28 days, respectively. At the end of the study, the pups were anesthetized, and the hearts were dissected out to measure oxidative stress indices, including the levels of Malondialdehyde (MDA), Nitric oxide (NO), Glutathione (GSH), and the activity of Superoxide dismutase (SOD). Our findings indicated that BUP did not alter MDA, NO, GSH levels, nor SOD activity in the cardiac tissue of pups exposed to this drug during the fetal period and through breast milk. We suggest performing additional studies to determine the association between BUP and oxidative modifications in cardiac tissues of pups born to mothers under BUP therapy during gestation and lactation.

A Review on the Vagus Nerve and Autonomic Nervous System During Fetal Development: Searching for Critical Windows

The autonomic nervous system (ANS) is one of the main biological systems that regulates the body's physiology. Autonomic nervous system regulatory capacity begins before birth as the sympathetic and parasympathetic activity contributes significantly to the fetus' development. In particular, several studies have shown how vagus nerve is involved in many vital processes during fetal, perinatal, and postnatal life: from the regulation of inflammation through the anti-inflammatory cholinergic pathway, which may affect the functioning of each organ, to the production of hormones involved in bioenergetic metabolism. In addition, the vagus nerve has been recognized as the primary afferent pathway capable of transmitting information to the brain from every organ of the body. Therefore, this hypothesis paper aims to review the development of ANS during fetal and perinatal life, focusing particularly on the vagus nerve, to identify possible "critical windows" that could impact its maturation. These "critical windows" could help clinicians know when to monitor fetuses to effectively assess the developmental status of both ANS and specifically the vagus nerve. In addition, this paper will focus on which factors-i.e., fetal characteristics and behaviors, maternal lifestyle and pathologies, placental health and dysfunction, labor, incubator conditions, and drug exposure-may have an impact on the development of the vagus during the above-mentioned "critical window" and how. This analysis could help clinicians and stakeholders define precise guidelines for improving the management of fetuses and newborns, particularly to reduce the potential adverse environmental impacts on ANS development that may lead to persistent long-term consequences. Since the development of ANS and the vagus influence have been shown to be reflected in cardiac variability, this paper will rely in particular on studies using fetal heart rate variability (fHRV) to monitor the continued growth and health of both animal and human fetuses. In fact, fHRV is a non-invasive marker whose changes have been associated with ANS development, vagal modulation, systemic and neurological inflammatory reactions, and even fetal distress during labor.

Prenatal exposure to opioids: Associations between the caregiving environment and externalizing behaviors

Maternal opioid use during pregnancy is a rapidly growing public health crisis and is associated with a range of adverse developmental outcomes including externalizing behaviors among exposed children. Recent work has highlighted the role of indirect pathways from prenatal opioid exposure to behavioral outcomes through aspects of the caregiving environment, including parenting. This review highlights maternal sensitivity and related aspects of the caregiving environment that may impact the development of externalizing behaviors among children with a history of prenatal exposure to opioids. We conclude by providing suggestions for future directions in research examining development among children with prenatal opioid exposure.

Exposures influencing the developing central autonomic nervous system

Autonomic nervous system function is critical for transition from in-utero to ex-utero life and is associated with neurodevelopmental and neuropsychiatric outcomes later in life. Adverse prenatal and neonatal conditions and exposures can impair or alter ANS development and, as a result, may also impact long-term neurodevelopmental outcomes. The objective of this article is to provide a broad overview of the impact of factors that are known to influence autonomic development during the fetal and early neonatal period, including maternal mood and stress during and after pregnancy, fetal growth restriction, congenital heart disease, toxic exposures, and preterm birth. We touch briefly on the typical development of the ANS, then delve into both in-utero and ex-utero maternal and fetal factors that may impact developmental trajectory of the ANS and, thus, have implications in transition and in long-term developmental outcomes. While many types of exposures and conditions have been shown to impact development of the autonomic nervous system, there is still much to be learned about the mechanisms underlying these influences. In the future, more advanced neuromonitoring tools will be required to better understand autonomic development and its influence on long-term neurodevelopmental and neuropsychological function, especially during the fetal period.

Methadone Suppresses Neuronal Function and Maturation in Human Cortical Organoids

Accumulating evidence has suggested that prenatal exposure to methadone causes multiple adverse effects on human brain development. Methadone not only suppresses fetal neurobehavior and alters neural maturation, but also leads to long-term neurological impairment. Due to logistical and ethical issues of accessing human fetal tissue, the effect of methadone on brain development and its underlying mechanisms have not been investigated adequately and are therefore not fully understood. Here, we use human cortical organoids which resemble fetal brain development to examine the effect of methadone on neuronal function and maturation during early development. During development, cortical organoids that are exposed to clinically relevant concentrations of methadone exhibited suppressed maturation of neuronal function. For example, organoids developed from 12th week till 24th week have an about 7-fold increase in AP firing frequency, but only half and a third of this increase was found in organoids exposed to 1 and 10 μM methadone, respectively. We further demonstrated substantial increases in I_Na (4.5-fold) and I_KD (10.8-fold), and continued shifts of Na⁺ channel activation and inactivation during normal organoid development. Methadone-induced suppression of neuronal function was attributed to the attenuated increase in the densities of I_Na and I_KD and the reduced shift of Na⁺ channel gating properties. Since normal neuronal electrophysiology and ion channel function are critical for regulating brain development, we believe that the effect of prolonged methadone exposure contributes to the delayed maturation, development fetal brain and potentially for longer term neurologic deficits.

Maintenance agonist treatments for opiate-dependent pregnant women

BACKGROUND

The prevalence of opiate use among pregnant women can range from 1% to 2% to as high as 21%. Just in the United States alone, among pregnant women with hospital delivery, a fourfold increase in opioid use is reported from 1999 to 2014 (Haight 2018). Heroin crosses the placenta, and pregnant, opiate-dependent women experience a six-fold increase in maternal obstetric complications such as low birth weight, toxaemia, third trimester bleeding, malpresentation, puerperal morbidity, fetal distress and meconium aspiration. Neonatal complications include narcotic withdrawal, postnatal growth deficiency, microcephaly, neuro-behavioural problems, increased neonatal mortality and a 74-fold increase in sudden infant death syndrome. This is an updated version of the original Cochrane Review first published in 2008 and last updated in 2013.

OBJECTIVES

To assess the effectiveness of any maintenance treatment alone or in combination with a psychosocial intervention compared to no intervention, other pharmacological intervention or psychosocial interventions alone for child health status, neonatal mortality, retaining pregnant women in treatment, and reducing the use of substances.

SEARCH METHODS

We updated our searches of the following databases to February 2020: the Cochrane Drugs and Alcohol Group Specialised Register, CENTRAL, MEDLINE, Embase, PsycINFO, CINAHL, and Web of Science. We also searched two trials registers and checked the reference lists of included studies for further references to relevant randomised controlled trials (RCTs).

SELECTION CRITERIA

Randomised controlled trials which assessed the efficacy of any pharmacological maintenance treatment for opiate-dependent pregnant women.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by Cochrane.

MAIN RESULTS

We found four trials with 271 pregnant women. Three compared methadone with buprenorphine and one methadone with oral slow-release morphine. Three out of four studies had adequate allocation concealment and were double-blind. The major flaw in the included studies was attrition bias: three out of four had a high dropout rate (30% to 40%), and this was unbalanced between groups. Methadone versus buprenorphine: There was probably no evidence of a difference in the dropout rate from treatment (risk ratio (RR) 0.66, 95% confidence interval (CI) 0.37 to 1.20, three studies, 223 participants, moderate-quality evidence). There may be no evidence of a difference in the use of primary substances between methadone and buprenorphine (RR 1.81, 95% CI 0.70 to 4.68, two studies, 151 participants, low-quality evidence). Birth weight may be higher in the buprenorphine group in the two trials that reported data MD;-530.00 g, 95%CI -662.78 to -397.22 (one study, 19 particpants) and MD: -215.00 g, 95%CI -238.93 to -191.07 (one study, 131 participants) although the results could not be pooled due to very high heterogeneity (very low-quality of evidence). The third study reported that there was no evidence of a difference. We found there may be no evidence of a difference in the APGAR score (MD: 0.00, 95% CI -0.03 to 0.03, two studies,163 participants, low-quality evidence). Many measures were used in the studies to assess neonatal abstinence syndrome. The number of newborns treated for neonatal abstinence syndrome, which is the most critical outcome, may not differ between groups (RR 1.19, 95% CI 0.87 to1.63, three studies, 166 participants, low-quality evidence). Only one study which compared methadone with buprenorphine reported side effects. We found there may be no evidence of a difference in the number of mothers with serious adverse events (AEs) (RR 1.69, 95% CI 0.75 to 3.83, 175 participants, low-quality evidence) and we found there may be no difference in the numbers of newborns with serious AEs (RR 4.77, 95% CI 0.59, 38.49,131 participants, low-quality evidence). Methadone versus slow-release morphine: There were no dropouts in either treatment group. Oral slow-release morphine may be superior to methadone for abstinence from heroin use during pregnancy (RR 2.40, 95% CI 1.00 to 5.77, one study, 48 participants, low-quality evidence). In the comparison between methadone and slow-release morphine, no side effects were reported for the mother. In contrast, one child in the methadone group had central apnoea, and one child in the morphine group had obstructive apnoea (low-quality evidence).

AUTHORS' CONCLUSIONS

Methadone and buprenorphine may be similar in efficacy and safety for the treatment of opioid-dependent pregnant women and their babies. There is not enough evidence to make conclusions for the comparison between methadone and slow-release morphine. Overall, the body of evidence is too small to make firm conclusions about the equivalence of the treatments compared. There is still a need for randomised controlled trials of adequate sample size comparing different maintenance treatments.

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: The next neonatal neuroinflammatory disease

The rates of opioid use disorder during pregnancy have more than quadrupled in the last decade, resulting in numerous infants suffering exposure to opioids during the perinatal period, a critical period of central nervous system (CNS) development. Despite increasing use, the characterization and definition of the molecular and cellular mechanisms of the long-term neurodevelopmental impacts of opioid exposure commencing in utero remains incomplete. Thus, in consideration of the looming public health crisis stemming from the multitude of infants with prenatal opioid exposure entering school age, we undertook an investigation of the effects of perinatal methadone exposure in a novel preclinical model. Specifically, we examined the effects of opioids on the developing brain to elucidate mechanisms of putative neural cell injury, to identify diagnostic biomarkers and to guide clinical studies of outcome and follow-up. We hypothesized that methadone would induce a pronounced inflammatory profile in both dams and their pups, and be associated with immune system dysfunction, sustained CNS injury, and altered cognition and executive function into adulthood. This investigation was conducted using a combination of cellular, molecular, biochemical, and clinically translatable biomarker, imaging and cognitive assessment platforms. Data reveal that perinatal methadone exposure increases inflammatory cytokines in the neonatal peripheral circulation, and reprograms and primes the immune system through sustained peripheral immune hyperreactivity. In the brain, perinatal methadone exposure not only increases chemokines and cytokines throughout a crucial developmental period, but also alters microglia morphology consistent with activation, and upregulates TLR4 and MyD88 mRNA. This increase in neuroinflammation coincides with reduced myelin basic protein and altered neurofilament expression, as well as reduced structural coherence and significantly decreased fractional anisotropy on diffusion tensor imaging. In addition to this microstructural brain injury, adult rats exposed to methadone in the perinatal period have significant impairment in associative learning and executive control as assessed using touchscreen technology. Collectively, these data reveal a distinct systemic and neuroinflammatory signature associated with prenatal methadone exposure, suggestive of an altered CNS microenvironment, dysregulated developmental homeostasis, complex concurrent neural injury, and imaging and cognitive findings consistent with clinical literature. Further investigation is required to define appropriate therapies targeted at the neural injury and improve the long-term outcomes for this exceedingly vulnerable patient population.

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.

Maternal buprenorphine treatment during pregnancy and maternal physiology

BACKGROUND

Buprenorphine, used for opioid use disorder (OUD) treatment during pregnancy, provides unknown effects on maternal physiological activity. The primary aim of this report is to document acute effects of buprenorphine administration on indicators of maternal autonomic functioning. Effects of maternal buprenorphine dose and other substance exposures on maternal measures were examined, as were neonatal abstinence syndrome (NAS) outcomes.

METHODS

Forty-nine pregnant, buprenorphine-maintained women yielded maternal physiologic information (heart rate and variability, electrodermal activity, and respiratory rate) at 24, 28, 32 and 36 weeks gestation. Monitoring at trough and peak maternal medication levels was implemented to ascertain acute physiologic effects of buprenorphine administration.

RESULTS

Buprenorphine administration accelerated maternal heart rate and reduced variability at two gestational ages (24 and 36 weeks) and suppressed sympathetic (electrodermal) activation at 24, 28 and 32 weeks at times of peak maternal medication levels. Maternal autonomic parameters were unrelated to polysubstance exposure with the exception of cigarette smoking. Heavier smoking dampened maternal heart rate variability across gestation and potentiated reactivity to buprenorphine at 24 and 36 weeks. Heavier smoking was also associated with reduced electrodermal activity at 36 weeks. Buprenorphine dose was unrelated to observed effects. Larger degree of maternal heart rate reactivity to buprenorphine administration was related to more severe NAS expression.

CONCLUSIONS

These findings detail the maternal autonomic response to buprenorphine administration but also illustrate the significant effect of concurrent cigarette use on maternal autonomic regulation. This suggests the importance of smoking-reduction strategies in the comprehensive, medication-assisted treatment of women with OUD.

Obstetric management of women with opioid use disorder

Pregnancy presents a window of opportunity for effecting positive change in the lives of women with opioid use disorder (OUD). Care should be empathetic and nonjudgmental with a focus on counseling for initiation and maintenance of beneficial health behaviors as well as development of a strong patient-provider relationship.¹ These include adherence to treatment of OUD through pharmacotherapy and behavioral counseling, smoking cessation, healthy nutrition, treatment of coexisting medical and psychosocial conditions, as well as preparation for the postpartum period through breastfeeding education and antenatal discussion of contraception. Women will also benefit from anticipatory guidance with regard to neonatal abstinence syndrome (see Chapter 7). This may include a consultation with pediatric or neonatal providers who will be caring for their infants. In the absence of other obstetric indications, minimal additional fetal assessment outside that of standard prenatal care is recommended for OUD.

Early life stress and environmental influences on the neurodevelopment of children with prenatal opioid exposure

Prenatal opioid exposure has reached epidemic proportions. In the last 10 years, there has been a 242% increase in the number of babies born with the drug withdrawal syndrome known as Neonatal Opioid Withdrawal Syndrome (NOWS). Developmental outcome studies of infants with prenatal opioid exposure are limited by methodological issues including small sample sizes and lack of control for confounding variables such as exposure to poverty and maternal psychopathology. Thus, there is a critical gap in the literature that limits our ability to predict short-term effects of opioid exposure. Here we review direct neurotoxic, indirect, and stress-related pathophysiologies of prenatal opioid exposure. We describe the literature on short and long-term neurodevelopmental outcomes of children with prenatal opioid exposure, highlighting sex differences and the role of early life stress. We conclude by prioritizing avenues for future research for this group of underserved women and their children at risk for neurodevelopmental delays.

Fetal assessment in buprenorphine-maintained women using fetal magnetoencephalography: a pilot study

BACKGROUND AND AIMS

In-utero exposure to opioids including buprenorphine (BUP) has been shown to affect fetal activity, specifically heart-rate variability (FHRV) and fetal movement (FM). Our objective was to extract simultaneous recordings of fetal cardiac and brain-related activity in BUP-maintained and non-opioid exposed pregnant women using a novel non-invasive biomagnetic technique.

DESIGN

A pilot study was conducted, recording and analyzing biomagnetic data from fetuses of BUP-maintained and non-opioid exposed pregnant women. Signals were acquired with the non-invasive 151-channel SARA (SQUID-Array for Reproductive Assessment) system. Advanced signal-processing techniques were applied to extract fetal heart and brain activity.

SETTING

University of Arkansas for Medical Sciences (UAMS, Little Rock, Arkansas, USA).

PARTICIPANTS

Eight BUP-maintained pregnant women from UAMS Women's Mental Health Program between gestational ages (GA) of 29-37 weeks who were treated with 8-24 mg of BUP daily. Sixteen pregnant women with no known opioid exposure in the same GA range were also included.

MEASUREMENTS

Outcome measures from the fetal heart and brain signals included: heart rate (FHR), FM, FHR accelerations, FHR-FM coupling, FHRV, fetal behavioral states (FBS) and power spectral density (PSD) of spontaneous brain activity. These measures were analyzed at three GA intervals.

FINDINGS

Fetal heart and brain activity parameters were extracted and quantified successfully from 18 non-opioid and 16 BUP recordings. Overall analysis in both groups show that: FHR and FM ranged from 131 to 141 beats per minute (b.p.m.) and 5 to 11 counts, respectively. In the 35-37 weeks GA, the coupling duration (~9 s) was the shortest, while three of the FHRV parameters were the highest. The PSD of brain activity revealed highest power in 0.5-4 Hz bandwidth. Transitions in FBS from quiet to active sleep were > 50% of sessions.

CONCLUSIONS

This pilot study showed that a novel biomagnetic technique allows simultaneous quantification of cardiac and brain activities of a group of buprenorphine-exposed and non-exposed fetuses in the third trimester.

Expression of kappa opioid receptors in developing rat brain - Implications for perinatal buprenorphine exposure

Buprenorphine, a mu opioid receptor partial agonist and kappa opioid receptor (KOR) antagonist, is an emerging therapeutic agent for maternal opioid dependence in pregnancy and neonatal abstinence syndrome. However, the endogenous opioid system plays a critical role in modulating neurodevelopment and perinatal buprenorphine exposure may detrimentally influence this. To identify aspects of neurodevelopment vulnerable to perinatal buprenorphine exposure, we defined KOR protein expression and its cellular associations in normal rat brain from embryonic day 16 to postnatal day 23 with double-labelling immunohistochemistry. KOR was expressed on neural stem and progenitor cells (NSPCs), choroid plexus epithelium, subpopulations of cortical neurones and oligodendrocytes, and NSPCs and subpopulations of neurones in postnatal hippocampus. These distinct patterns of KOR expression suggest several pathways vulnerable to perinatal buprenorphine exposure, including proliferation, neurogenesis and neurotransmission. We thus suggest the cautious use of buprenorphine in both mothers and infants until its impact on neurodevelopment is better defined.

Prenatal buprenorphine exposure and neonatal neurobehavioral functioning

AIMS

Assessments of effects of prenatal opioid exposure on the neonate have consisted principally of evaluations of neonatal abstinence syndrome (NAS) to determine the need for pharmacotherapy. The purpose of this study was to comprehensively evaluate the effects of gestational maternal buprenorphine maintenance on newborn neurobehavioral functioning.

STUDY DESIGN

Maternal substance use history and psychosocial demographics that can contribute to the neurobehavioral functioning of the infant were explored. Infants were assessed using the NICU Network Neurobehavioral Scale (NNNS) to measure their neurologic and behavioral functioning and signs of stress/abstinence on days 3, 14 and 30 of life.

SUBJECTS

Participants were 41 pregnant buprenorphine-maintained women and their infants.

RESULTS

Maternal buprenorphine dose at delivery was negatively correlated with infant quality of movement and self-regulation, and positively correlated with the central nervous system parameters of stress/abstinence at day 3 of life. As maternal buprenorphine dose increased, the mean morphine dose that the infant required for NAS treatment significantly increased. No differences were found when comparing the NNNS domain scores between infants who required pharmacotherapy for NAS versus those who did not at day 3 of life.

CONCLUSIONS

Buprenorphine exposure during pregnancy can alter neonatal neurobehavioral and physiological responses to stimuli. A systematic evaluation of the newborn's functional domains above NAS assessment alone is crucial to address the challenges created by neurobehavioral dysregulation associated with substance exposure, improve caregiver/infant interaction and developmental trajectory. Comprehensive pre/postnatal treatment of buprenorphine-maintained mothers can lead to healthier outcomes for the dyad.

Treating Women Who Are Pregnant and Parenting for Opioid Use Disorder and the Concurrent Care of Their Infants and Children: Literature Review to Support National Guidance

OBJECTIVES

The prevalence of opioid use disorder (OUD) during pregnancy is increasing. Practical recommendations will help providers treat pregnant women with OUD and reduce potentially negative health consequences for mother, fetus, and child. This article summarizes the literature review conducted using the RAND/University of California, Los Angeles Appropriateness Method project completed by the US Department of Health and Human Services Substance Abuse and Mental Health Services Administration to obtain current evidence on treatment approaches for pregnant and parenting women with OUD and their infants and children.

METHODS

Three separate search methods were employed to identify peer-reviewed journal articles providing evidence on treatment methods for women with OUD who are pregnant or parenting, and for their children. Identified articles were reviewed for inclusion per study guidelines and relevant information was abstracted and summarized.

RESULTS

Of the 1697 articles identified, 75 were included in the literature review. The perinatal use of medication for addiction treatment (MAT, also known as medication-assisted treatment), either methadone or buprenorphine, within comprehensive treatment is the most accepted clinical practice, as withdrawal or detoxification risks relapse and treatment dropout. Medication increases may be needed with advancing pregnancy, and are not associated with more severe neonatal abstinence syndrome (NAS). Switching medication prenatally is usually not recommended as it can destabilize opioid abstinence. Postnatally, breastfeeding is seen as beneficial for the infant for women who are maintained on a stable dose of opioid agonist medication. Less is known about ideal pain management and postpartum dosing regimens. NAS appears generally less severe following prenatal exposure to buprenorphine versus methadone. Frontline NAS medication treatments include protocol-driven methadone and morphine dosing in the context of nonpharmacological supports.

CONCLUSIONS

Women with OUD can be treated with methadone or buprenorphine during pregnancy. NAS is an expected and manageable condition. Although research has substantially advanced, opportunities to guide future research to improve maternal and infant outcomes are provided.

Neonatal abstinence syndrome: Neurobehavior at 6 weeks of age in infants with or without pharmacological treatment for withdrawal

Use and abuse of prescription opioids and concomitant increase in Neonatal Abstinence Syndrome (NAS), a condition that may lead to protracted pharmacological treatment in more than 60% of infants, has tripled since 2000. This study assessed neurobehavioral development using the NICU Network Neurobehavioral Scale in 6-week old infants with prenatal methadone exposure who did (NAS+; n = 23) or did not (NAS-; n = 16) require pharmacological treatment for NAS severity determined by Finnegan Scale. An unexposed, demographically similar group of infants matched for age served as comparison (COMP; n = 21). NAS+, but not NAS- group, had significantly lower scores on the regulation (p < .01) and quality of movement (p < .01) summary scales than the COMP group. The NAS+ and NAS- groups had higher scores on the stress-abstinence scale than the COMP group (p < .05). NAS diagnosis (NAS +) was associated with poorer regulation and quality of movement at 6 weeks of age compared to infants without prenatal methadone exposure from the same demographic.

Maternal buprenorphine treatment and fetal neurobehavioral development

BACKGROUND

Gestational opioid use/misuse is escalating in the United States; however, little is understood about the fetal effects of medications used to treat maternal opioid use disorders.

OBJECTIVE

The purpose of this study was to determine the effect of maternal buprenorphine administration on longitudinal fetal neurobehavioral development.

STUDY DESIGN

Forty-nine buprenorphine-maintained women who attended a substance use disorder treatment facility with generally uncomplicated pregnancies underwent fetal monitoring for 60 minutes at times of trough and peak maternal buprenorphine levels. Data were collected at 24, 28, 32, and 36 weeks gestation. Fetal neurobehavioral indicators (ie, heart rate, motor activity, and their integration [fetal movement-fetal heart rate coupling]) were collected via an actocardiograph, digitized and quantified. Longitudinal data analysis relied on hierarchic linear modeling.

RESULTS

Fetal heart rate, heart rate variability, and heart rate accelerations were significantly reduced at peak vs trough maternal buprenorphine levels. Effects were significant either by or after 28 weeks gestation and tended to intensify with advancing gestation. Fetal motor activity and fetal movement-fetal heart rate coupling were depressed from peak to trough at 36 weeks gestation. Polysubstance exposure did not significantly affect fetal neurobehavioral parameters, with the exception that fetuses of heavier smokers moved significantly less than those of lighter smokers at 36 weeks gestation. By the end of gestation, higher maternal buprenorphine dose was related to depression of baseline fetal cardiac measures at trough.

CONCLUSION

Maternal buprenorphine administration has acute suppressive effects on fetal heart rate and movement, and the magnitude of these effects increases as gestation progresses. Higher dose (≥13 mg) appears to exert greater depressive effects on measures of fetal heart rate and variability. These findings should be balanced against comparisons to gestational methadone effects, relatively good outcomes of buprenorphine-exposed infants, and recognition of the benefits of medication-assisted treatment for pregnant women with opioid use disorders in optimizing pregnancy outcomes.

Maternal-Fetal Monitoring of Opioid-Exposed Pregnancies: Analysis of a Pilot Community-Based Protocol and Review of the Literature

OBJECTIVES

To describe/analyse a novel, community-based prenatal monitoring protocol for opioid-exposed pregnancies developed by our centre in 2014 to optimize prenatal care for this population. A literature review of published monitoring protocols for this population is also presented.

METHODS

Retrospective comparison of pre-protocol (n = 215) and post-protocol (n = 251) cohorts. Medline and Embase were searched between 2000-2016 using MeSH terms: [fetal monitoring OR prenatal care] AND [opioid-related disorders OR substance-related disorders] in Medline and [fetal monitoring OR prenatal care] AND [opiate addiction OR substance abuse] in Embase, producing 518 results. Thirteen studies included protocols for monitoring opioid-exposed pregnancies. No comprehensive monitoring protocols with high-quality supporting evidence were found.

RESULTS

We evaluated 466 opioid-exposed pregnancies, 215 before and 251 after introduction of the protocol. Since implementation, there was a significant increase in the number of opioid-exposed patients who have underwent urine drug screening (72.6% to 89.2%, P < 0.0001); a significant reduction in the number of urine drug screenings positive for illicit opioids (50.2% to 29.1%, P < 0.0001); and a significant increase in the number of patients who discontinued illicit opioid use by the time of delivery (24.7% to 39.4%, P < 0.01). There was no difference in the CS rate (27.4% vs. 26.3%, P > 0.05). There were no observed differences in the rate of preterm birth, birth weight <2500 g, or Apgar score <7 (P > 0.05).

CONCLUSIONS

Care of women with increased opioid use during pregnancy is an important but under-studied health issue. A novel protocol for focused antenatal care provision for women with opioid-exposed pregnancies improves standard of care and maternal/fetal outcomes.

Buprenorphine compared with methadone to treat pregnant women with opioid use disorder: a systematic review and meta-analysis of safety in the mother, fetus and child

AIMS

To assess the safety of buprenorphine compared with methadone to treat pregnant women with opioid use disorder.

METHODS

We searched PubMed, Embase and the Cochrane Library from inception to February 2015 for randomized controlled trials (RCT) and observational cohort studies (OBS) that compared buprenorphine with methadone for treating opioid-dependent pregnant women. Two reviewers assessed independently the titles and abstracts of all search results and full texts of potentially eligible studies reporting original data for maternal/fetal/infant death, preterm birth, fetal growth outcomes, fetal/congenital anomalies, fetal/child neurodevelopment and/or maternal adverse events. We ascertained each study's risk of bias using validated instruments and assessed the strength of evidence for each outcome using established methods. We computed effect sizes using random-effects models for each outcome with two or more studies.

RESULTS

Three RCTs (n = 223) and 15 cohort OBSs (n = 1923) met inclusion criteria. In meta-analyses using unadjusted data and methadone as comparator, buprenorphine was associated with lower risk of preterm birth [RCT risk ratio (RR) = 0.40, 95% confidence interval (CI) = 0.18, 0.91; OBS RR = 0.67, 95% CI = 0.50, 0.90], greater birth weight [RCT weighted mean difference (WMD) = 277 g, 95% CI = 104, 450; OBS WMD = 265 g, 95% CI = 196, 335] and larger head circumference [RCT WMD = 0.90 cm, 95% CI = 0.14, 1.66; OBS WMD = 0.68 cm, 95% CI = 0.41, 0.94]. No treatment differences were observed for spontaneous fetal death, fetal/congenital anomalies and other fetal growth measures, although the power to detect such differences may be inadequate due to small sample sizes.

CONCLUSIONS

Moderately strong evidence indicates lower risk of preterm birth, greater birth weight and larger head circumference with buprenorphine treatment of maternal opioid use disorder during pregnancy compared with methadone treatment, and no greater harms.

Mother-child interaction and cognitive development in children prenatally exposed to methadone or buprenorphine

OBJECTIVE

To assess the influence of mother-child interaction on children's cognitive development in a group of children prenatally exposed to methadone or buprenorphine.

STUDY DESIGN

The study is part of a prospective longitudinal project investigating the development of children born to women in opioid maintenance therapy (OMT). The sample includes 67 children born between 2005 and 2007, 35 of which prenatally exposed to either methadone or buprenorphine and 32 non-exposed comparison children.

RESULTS

Both groups scored within the normal range of development. However, the OMT group scored significantly lower on measures of cognitive development and mother-child interaction compared to the comparison group. Cognitive development was found to be affected by both group status, F(1,54)=5.65, p=0.02, η(2)=0.10 and mother-child interaction F(1,54)=5.26, p=0.03, η(2)=0.09. Behavioral inhibition (statue), sensorimotor function (imitating hand positions), and short-term memory (sentences) was influenced by group status while narrative memory and vocabulary were found to be more influenced by mother-child interaction.

CONCLUSIONS

Different risk factors may influence different cognitive functions in children of women in OMT. Specifically, language-related cognitive skills may be more related to mother-child interaction while performance in higher cognitive functions requiring precise control over sensorimotor responses may be more sensitive to other factors such as prenatal OMT exposure, genetics, and/or prenatal exposure to other substances.

Maintenance agonist treatments for opiate-dependent pregnant women

BACKGROUND

The prevalence of opiate use among pregnant women can range from 1% to 2% to as high as 21%. Heroin crosses the placenta and pregnant, opiate-dependent women experience a six-fold increase in maternal obstetric complications such as low birth weight, toxaemia, third trimester bleeding, malpresentation, puerperal morbidity, fetal distress and meconium aspiration. Neonatal complications include narcotic withdrawal, postnatal growth deficiency, microcephaly, neuro-behavioural problems, increased neonatal mortality and a 74-fold increase in sudden infant death syndrome.

OBJECTIVES

To assess the effectiveness of any maintenance treatment alone or in combination with psychosocial intervention compared to no intervention, other pharmacological intervention or psychosocial interventions for child health status, neonatal mortality, retaining pregnant women in treatment and reducing the use of substances.

SEARCH METHODS

We searched the Cochrane Drugs and Alcohol Group Trials Register (September 2013), PubMed (1966 to September 2013), CINAHL (1982 to September 2013), reference lists of relevant papers, sources of ongoing trials, conference proceedings and national focal points for drug research. We contacted authors of included studies and experts in the field.

SELECTION CRITERIA

Randomised controlled trials assessing the efficacy of any maintenance pharmacological treatment for opiate-dependent pregnant women.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

We found four trials with 271 pregnant women. Three compared methadone with buprenorphine and one methadone with oral slow-release morphine. Three out of four studies had adequate allocation concealment and were double-blind. The major flaw in the included studies was attrition bias: three out of four had a high drop-out rate (30% to 40%) and this was unbalanced between groups.Methadone versus buprenorphine: the drop-out rate from treatment was lower in the methadone group (risk ratio (RR) 0.64, 95% confidence interval (CI) 0.41 to 1.01, three studies, 223 participants). There was no statistically significant difference in the use of primary substance between methadone and buprenorphine (RR 1.81, 95% CI 0.70 to 4.69, two studies, 151 participants). For both, we judged the quality of evidence as low. Birth weight was higher in the buprenorphine group in the two trials that could be pooled (mean difference (MD) -365.45 g (95% CI -673.84 to -57.07), two studies, 150 participants). The third study reported that there was no statistically significant difference. For APGAR score neither of the studies which compared methadone with buprenorphine found a significant difference. For both, we judged the quality of evidence as low. Many measures were used in the studies to assess neonatal abstinence syndrome. The number of newborns treated for neonatal abstinence syndrome, which is the most critical outcome, did not differ significantly between groups. We judged the quality of evidence as very low.Methadone versus slow-release morphine: there was no drop-out in either treatment group. Oral slow-release morphine seemed superior to methadone for abstinence from heroin use during pregnancy (RR 2.40, 95% CI 1.00 to 5.77, one study, 48 participants). We judged the quality of evidence as moderate.Only one study which compared methadone with buprenorphine reported side effects. For the mother there was no statistically significant difference; for the newborns in the buprenorphine group there were significantly fewer serious side effects.In the comparison between methadone and slow-release morphine no side effects were reported for the mother, whereas one child in the methadone group had central apnoea and one child in the morphine group had obstructive apnoea.

AUTHORS' CONCLUSIONS

We did not find sufficient significant differences between methadone and buprenorphine or slow-release morphineto allow us to conclude that one treatment is superior to another for all relevant outcomes. While methadone seems superior in terms of retaining patients in treatment, buprenorphine seems to lead to less severe neonatal abstinence syndrome. Additionally, even though a multi-centre, international trial with 175 pregnant women has recently been completed and its results published and included in this review, the body of evidence is still too small to draw firm conclusions about the equivalence of the treatments compared. There is still a need for randomised controlled trials of adequate sample size comparing different maintenance treatments.

Depression-like effect of prenatal buprenorphine exposure in rats

Studies indicate that perinatal opioid exposure produces a variety of short- and long-term neurobehavioral consequences. However, the precise modes of action are incompletely understood. Buprenorphine, a mixed agonist/antagonist at the opioid receptors, is currently being used in clinical trials for managing pregnant opioid addicts. This study provides evidence of depression-like consequence following prenatal exposure to supra-therapeutic dose of buprenorphine and sheds light on potential mechanisms of action in a rat model involving administration of intraperitoneal injection to pregnant Sprague-Dawley rats starting from gestation day 7 and lasting for 14 days. Results showed that pups at postnatal day 21 but not the dams had worse parameters of depression-like neurobehaviors using a forced swimming test and tail suspension test, independent of gender. Neurobehavioral changes were accompanied by elevation of oxidative stress, reduction of plasma levels of brain-derived neurotrophic factor (BDNF) and serotonin, and attenuation of tropomyosin-related kinase receptor type B (TrkB) phosphorylation, extracellular signal-regulated kinase (ERK) phosphorylation, protein kinase A activity, cAMP response element-binding protein (CREB) phosphorylation, and CREB DNA-binding activity. Since BDNF/serotonin and CREB signaling could orchestrate a positive feedback loop, our findings suggest that the induction of oxidative stress, reduction of BDNF and serotonin expression, and attenuation of CREB signaling induced by prenatal exposure to supra-therapeutic dose of buprenorphine provide evidence of potential mechanism for the development of depression-like neurobehavior.

Prenatal buprenorphine exposure decreases neurogenesis in rats

Perinatal opioid exposure has a negative effect on neurogenesis and produces neurological consequences. However, its mechanisms of action are incompletely understood. Buprenorphine, a mixed opioid agonist/antagonist, is an alternative medication for managing pregnant opioid addicts. This study provides evidence of decreased neurogenesis and depression-like consequences following prenatal exposure to buprenorphine and sheds light on mechanisms of action in a rat model involving administration of intraperitoneal injection to pregnant rats starting from gestation day 7 and lasting for 14 days and a cultured neurosphere model. Results of forced swimming test and tail suspension test showed that pups at postnatal day 21 had worse parameters of depression-like neurobehaviors, independent of gender. Neurobehavioral changes were accompanied by reduction of neuronal composition, biochemical parameters of neural stem/progenitor cells, brain-derived neurotrophic factor (BDNF) expression, tropomyosin-related kinase receptor type B phosphorylation, protein kinase A (PKA) activity, and cAMP response element-binding protein phosphorylation. Results of parallel cell studies further demonstrated a negative impact of buprenorphine on cultured neurospheres, including proliferation, differentiation, BDNF expression and signaling, and PKA activity. Taken together, our results suggest that prenatal exposure to buprenorphine might result in depression-like phenotypes associated with impaired BDNF action and decreased neurogenesis in the developing brain of weanlings.

Perinatal outcomes of Australian buprenorphine-exposed mothers and their newborn infants

AIM

To determine the short-term outcomes of Australian buprenorphine-exposed mother/infant dyads.

METHODS

Retrospective record review of drug-exposed mothers and infants in Australia. Groups were based on drug exposure: buprenorphine (55, 3.8%), non-buprenorphine opiates (O, 686, 48.6%) and non-opiates (NO, 671, 47.5%).

RESULTS

More than 30% of buprenorphine mothers continued to use heroin (21, 38%) and benzodiazepines (16, 29%). They were more likely to have child at risk concerns (29, 52.7%, P = 0.019) and have previous children placed in out-of-home care (9, 16.3%, P = 049). Buprenorphine babies were less likely to be preterm (16% vs. 25% (O), P = 0.001 and 23% (NO), P = 0.004) and had higher birthweights (median: 3165 g vs. 2842.5 g (O), P < 0.001 and 2900 g (NO), P = 0.004). Buprenorphine and non-buprenorphine opioid babies had similar maximum Finnegan scores (median 10 vs. 11(O), P = 0.144). The number of babies needing abstinence treatment (45% vs. 51% (O), P = 0.411) and length of hospital stay (median days 9 vs. 11(O), P = 0.067) were similar, but buprenorphine infants required lower maximum morphine doses (mg/kg/day) (median 0.4 mg vs. 0.5 mg (O), P = 0.009).

CONCLUSIONS

Short-term medical outcomes of infants of buprenorphine-using mothers are similar to those of non-buprenorphine opiate-using mothers, but interpretation of these results is confounded by the high rates of polydrug exposure in the buprenorphine group. This and other social concerns noted in buprenorphine mothers and infants warrant further study.

Buprenorphine use in pregnant opioid users: a critical review

Pregnancy in opioid users poses a number of problems to treating physicians. Most guidelines recommend maintenance treatment to manage opioid addiction in pregnancy, with methadone being the gold standard. More recently, buprenorphine has been discussed as an alternate medication. The use and efficacy of buprenorphine in pregnancy is still controversial. This article reviews the current database on the basis of a detailed and critical literature search performed in MEDLINE (206 counts). Most of the relevant studies (randomised clinical trials and one national cohort sample) were published in the last 2 years and mainly compared buprenorphine with methadone. Some studies are related to maternal outcomes, others to foetal, neonatal or older child outcomes. With respect to maternal outcomes, most studies suggest that buprenorphine has similar effects to methadone. Very few data from small studies discuss an effect of buprenorphine on neurodevelopment of the foetus. Neonatal abstinence syndrome is common in infants of both buprenorphine- and methadone-maintained mothers. As regards neonatal outcomes, buprenorphine has the same clinical outcome as methadone, although some newer studies suggest that it causes fewer withdrawal symptoms. Since hardly any studies have investigated the combination of buprenorphine with naloxone (which has been suggested to possibly have teratogenic effects) in pregnant women, a switch to buprenorphine monotherapy is recommended in women who become pregnant while receiving the combination product. These novel findings indicate that buprenorphine is emerging as a first-line treatment for pregnant opioid users.

The effect of abused substances on antenatal and intrapartum fetal testing and well-being

Recognition that use and abuse of substances by pregnant patients perpetuates, despite ongoing efforts to educate the public, necessitates clinicians to integrate understanding of potential effects on antepartum and intrapartum fetal testing into their interpretation and implementation of clinical findings. This includes acknowledging some anticipated alterations in results and selecting the appropriate type and frequency of testing methods and interventions. Certain substances are well documented in terms of expected variations in test results; others are not as clearly defined. An overview of information that may be helpful to the clinician is presented to promote understanding of fetal evaluation performed through common tests such as contraction stress test, the nonstress test, the biophysical profile, the modified biophysical profile, fetal movement counting, and Doppler velocimetry. What evidence is available should be used to assist in defining the actual status of the fetus as best as possible, even when the effects of substances may be unknown or have obscure results.

Neonatal neurobehavior effects following buprenorphine versus methadone exposure

AIM

To determine the effects of in utero exposure to methadone or buprenorphine on infant neurobehavior.

DESIGN

Three sites from the Maternal Opioid Treatment: Human Experimental Research (MOTHER) study, a double-blind, double-dummy, randomized clinical trial participated in this substudy.

SETTING

Medical Centers that provided comprehensive maternal care to opioid-dependent pregnant women in Baltimore, MD, Providence, RI and Vienna, Austria.

PARTICIPANTS

Thirty-nine full-term infants.

MEASUREMENTS

The Neonatal Intensive Care Unit (NICU) Network Neurobehavioral Scale (NNNS) was administered to a subgroup of infants on postpartum days 3, 5, 7, 10, 14-15 and 28-30.

FINDINGS

While neurobehavior improved for both medication conditions over time, infants exposed in utero to buprenorphine exhibited fewer stress-abstinence signs (P < 0.001), were less excitable (P < 0.001) and less over-aroused (P < 0.01), exhibited less hypertonia (P < 0.007), had better self-regulation (P < 0.04) and required less handling (P < 0.001) to maintain a quiet alert state relative to in utero methadone-exposed infants. Infants who were older when they began morphine treatment for withdrawal had higher self-regulation scores (P < 0.01), and demonstrated the least amount of excitability (P < 0.02) and hypertonia (P < 0.02) on average. Quality of movement was correlated negatively with peak NAS score (P < 0.01), number of days treated with morphine for NAS (P < 0.01) and total amount of morphine received (P < 0.03). Excitability scores were related positively to total morphine dose (P < 0.03).

CONCLUSION

While neurobehavior improves during the first month of postnatal life for in utero agonist medication-exposed neonates, buprenorphine exposure results in superior neurobehavioral scores and less severe withdrawal than does methadone exposure.

Buprenorphine treatment of opioid-dependent pregnant women: a comprehensive review

AIMS

This paper reviews the published literature regarding outcomes following maternal treatment with buprenorphine in five areas: maternal efficacy, fetal effects, neonatal effects, effects on breast milk and longer-term developmental effects.

METHODS

Within each outcome area, findings are summarized first for the three randomized clinical trials and then for the 44 non-randomized studies (i.e. prospective studies, case reports and series and retrospective chart reviews), only 28 of which involve independent samples.

RESULTS

Results indicate that maternal treatment with buprenorphine has comparable efficacy to methadone, although difficulties may exist with current buprenorphine induction methods. The available fetal data suggest buprenorphine results in less physiological suppression of fetal heart rate and movements than methadone. Regarding neonatal effects, perhaps the single definitive conclusion is that prenatal buprenorphine treatment results in a clinically significant less severe neonatal abstinence syndrome (NAS) than treatment with methadone. The limited research suggests that, like methadone, buprenorphine is compatible with breastfeeding. Data available thus far suggest that there are no deleterious effects of in utero buprenorphine exposure on infant development.

CONCLUSIONS

While buprenorphine produces a less severe neonatal abstinence syndrome than methadone, both methadone and buprenorphine are important parts of a complete comprehensive treatment approach for opioid-dependent pregnant women.

Fetal assessment before and after dosing with buprenorphine or methadone

AIM

To determine pre- and post-dosing effects of prenatal methadone compared to buprenorphine on fetal wellbeing.

DESIGN

A secondary analysis of data derived from the Maternal Opioid Treatment: Human Experimental Research (MOTHER) study, a double-blind, double-dummy, randomized clinical trial.

SETTING

Six United States sites and one European site that provided comprehensive opioid-dependence treatment to pregnant women.

PARTICIPANTS

Eighty-one of the 131 opioid-dependent pregnant women completing the MOTHER clinical trial, assessed between 31 and 33 weeks of gestation.

MEASUREMENTS

Two fetal assessments were conducted, once before and once after study medication dosing. Measures included mean fetal heart rate (FHR), number of FHR accelerations, FHR reactivity in the fetal non-stress test (NST) and biophysical profile (BPP) score.

FINDINGS

Significant group differences were found for number of FHR accelerations, non-reactive NST and BPP scores (all Ps < 0.05). There were no significant group differences before time of dosing. Significant decreases (all Ps < 0.05) occurred from pre- to post-dose assessment for mean FHR, FHR accelerations, reactive NST and fetal movement. The decrease in accelerations and reactive NST were significant only for fetuses in the methadone group, and this resulted in a significantly lower likelihood of a reactive NST compared to fetuses in the buprenorphine group.

CONCLUSION

Buprenorphine compared with methadone appears to result in less suppression of mean fetal heart rate, fetal heart rate reactivity and the biophysical profile score after medication dosing and these findings provide support for the relative safety of buprenorphine when fetal indices are considered as part of the complete risk-benefit ratio.

Evaluation and management of opioid dependence in pregnancy

BACKGROUND

Opioid use disorders are a growing public health problem in the United States. Most women who are opioid-dependent are of childbearing age, and management of opioid dependence during pregnancy poses unique challenges. Assessment includes evaluation for addiction, withdrawal syndromes, and comorbid psychiatric diagnoses. Consultation-liaison (C-L) psychiatrists may also be involved in acute pain management, perinatal medication management, buprenorphine induction, and stabilization. For the past four decades, the standard of care has included methadone maintenance, but the increasing use of buprenorphine creates new treatment issues and opportunities.

OBJECTIVE

To educate C-L psychiatrists in emergency and obstetrical settings about the appropriate approach toward the evaluation and basic management of women with opioid dependence in pregnancy.

METHOD

The authors reviewed the consensus literature and all new treatment options on opioid dependence during pregnancy.

DISCUSSION

In this review, the authors summarize known and emerging management strategies for opioid dependence in pregnancy pertinent to C-L psychiatrists.

Neonatal abstinence syndrome

PURPOSE OF REVIEW

This review will discuss the complex nature of maternal and other factors that can affect the infant's display of neonatal abstinence syndrome (NAS), clinical presentation and treatment of NAS, and the impact of recent findings on future directions for research.

RECENT FINDINGS

NAS has traditionally been described as a constellation of signs/symptoms displayed by the neonate upon withdrawal of gestational opioid exposure; however, recent research has advanced our understanding of this disorder. Other psychoactive substances, such as increasingly prescribed serotonin reuptake inhibitors, may produce an independent or synergistic discontinuation syndrome. The wide variability in NAS presentation has generated interest in the interplay of prenatal and postnatal environmental and genetic factors that may moderate or mediate its expression. Finally, recent advances in the treatment of opioid-dependent pregnant women have suggested buprenorphine as an alternative treatment to methadone during pregnancy, largely due to reduced NAS severity in exposed neonates.

SUMMARY

Physicians should be aware of the complexity of the maternal, fetal, and infant factors that combine to create the infant's display of NAS, and incorporate these aspects into comprehensive assessment and care of the dyad. Further research regarding the pathophysiology and treatment of NAS is warranted.

Opioid dependency in pregnancy and length of stay for neonatal abstinence syndrome

OBJECTIVE

To examine opioid replacement therapy in pregnancy and effect on neonatal outcomes, including length of hospital stay for neonatal abstinence syndrome.

DESIGN

Retrospective descriptive study.

SETTING

Labor and delivery unit and neonatal intensive care unit (NICU), Eastern Maine Medical Center, Bangor, Maine.

PARTICIPANTS

One hundred fifty-two opioid-dependent pregnant women on methadone maintenance therapy (MMT) (n = 136) or buprenorphine maintenance therapy (BMT) (n = 16) during pregnancy and their neonates. The neonates were born between January 1, 2005 and December 31, 2007.

METHODS

A review of the electronic medical record (EMR) was conducted of all opioid-dependent women who were maintained on MMT or BMT at the time of admission for labor and delivery and their neonates.

RESULTS

Maternal methadone dose and concomitant in-utero exposure to benzodiazepines prolonged the length of hospital stay for neonates. Length of stay was shorter in breastfed neonates than formula-fed neonates or neonates who received formula and breast milk. Neonates with prenatal exposure to MMT spent more days in the hospital (21 vs. 14 days) for treatment of neonatal abstinence syndrome (NAS) than infants with prenatal exposure to BMT.

CONCLUSION

These findings are consistent with previous research on the simultaneous use of methadone and benzodiazepines during pregnancy and provide further direction for the treatment of opioid dependency during pregnancy. Harm reduction strategies for opioid-dependent pregnant women in substance abuse treatment with MMT may one day include guidance on daily treatment doses and recommendations to avoid the concomitant use of benzodiazepines to lessen NAS. Breastfeeding should be recommended to shorten length of stay. Understanding perinatal and neonatal outcomes of pregnant women on methadone or buprenorphine will help to identify optimal treatment for opioid dependency in pregnancy.

Comparing methadone and buprenorphine maintenance with methadone-assisted withdrawal for the treatment of opioid dependence during pregnancy: maternal and neonatal outcomes

Pregnancy can motivate opioid-dependent women to seek substance abuse treatment. Research has demonstrated that although prenatal exposure to buprenorphine results in less severe neonatal abstinence syndrome (NAS) relative to prenatal methadone exposure, the maternal and other neonatal outcomes are similar for the two medications. Maternal and neonatal outcomes for opioid-dependent pregnant women receiving these medications have not been systematically ompared with methadone-assisted withdrawal. The present study provides an initial assessment of the relative efficacy of both methadone and buprenorphine maintenance versus methadone-assisted withdrawal in terms of neonatal and maternal delivery outcomes. Data were derived from (1) the MOTHER (Maternal Opioid Treatment: Human Experimental Research) study at the Johns Hopkins University Bayview Medical Center (JHBMC), or (2) retrospective records review of women who underwent methadone-assisted withdrawal at the JHBMC during the time period in which participants were enrolled in the MOTHER study. Compared with the methadone maintenance group, the methadone-assisted withdrawal group had a significantly lower mean NAS peak score (Means = 13.7 vs 7.0; P = 0.002), required a significantly lower mean amount of morphine to treat NAS (Means = 82.8 vs 0.2; P < 0.001), had significantly fewer days medicated for NAS (Means = 31.5 vs 3.9; P < 0.001), and remained in the hospital for a significantly fewer number of days, on average (Means = 24.2 vs 7.0; P < 0.019). Compared with the buprenorphine maintenance group, the methadone-assisted withdrawal group required a significantly lower mean amount of morphine to treat NAS (Means = 8.2 vs 0.2; P < 0.001) and significantly fewer days medicated for NAS (Means = 12.0 vs 3.9; P = 0.008). Findings suggest that it is possible for some opioid-dependent pregnant women to succeed with methadone-assisted withdrawal. Future research needs to more fully evaluate the potential benefits and risks of methadone-assisted withdrawal for the maternal-fetal dyad.