Correlations of maternal buprenorphine dose, buprenorphine, and metabolite concentrations in meconium with neonatal outcomes

Is buprenorphine maternal dose associated with neonatal opioid withdrawal syndrome severity?

BACKGROUND

Neonatal opioid withdrawal syndrome (NOWS) is a drug withdrawal syndrome occurring mainly after in utero opioid exposure. Buprenorphine is commonly used for opioid withdrawal. Studies are conflicted about a potential dose effect OBJECTIVE: The aim of our study was to investigate the impact of buprenorphine maternal maintenance therapy on the NOWS based on NOWS duration, birth weight and therapy.

STUDY DESIGN

We conducted a retrospective study analysing data from infants admitted for NOWS in two Neonatal Intensive Care Unit between January 2010 and December 2020.

INCLUSION CRITERIA

Nonpreterm infants born to mothers who were treated with buprenorphine or therapy during pregnancy and who had a Lipsitz score of 4 or higher.

RESULTS

A total of 75 term newborns were hospitalized for the treatment of NOWS from mother substituted with buprenorphine during the study inclusion period. The duration of NOWS differed significantly between all dose cohorts, with higher doses of maternal buprenorphine maintenance correlating with longer length of NOWS duration. Infants exposed to high doses required 17 days [10; 23], while infants exposed to intermediate doses required 7 days [2; 16] and infants exposed to low doses required 3 days [2; 5], with p-values < .003. Infants exposed to high doses required a longer time to regain their birth weight and higher morphine doses as therapy compared to others. Infants exposed to low doses, intermediate doses, and high doses of buprenorphine demonstrated dose-dependent increases in the durations of hospitalization, respectively.

CONCLUSION AND SCIENTIFIC SIGNIFICANCE

Increased doses of maternal buprenorphine during pregnancy are correlated with NOWS severity. Our study shows that increased doses of maternal buprenorphine during pregnancy are correlated with NOWS severity. Exploring low doses and having different ranges are a new argument to define the impact of maternal buprenorphine consumption.

A Pharmacologic Evaluation of Buprenorphine in Pregnancy and the Postpartum Period

BACKGROUND

The dosing regimen in the package insert for sublingual buprenorphine is similar for pregnant and nonpregnant people despite the physiologic changes seen during pregnancy.

AIMS

To compare plasma buprenorphine pharmacokinetics during and after pregnancy and relate buprenorphine concentration to the pharmacodynamic endpoints of pupil diameter, Clinical Opioid Withdrawal Scale (COWS), and craving scores.

STUDY DESIGN

Prospective cohort of 22 pregnant people undergoing 33 pharmacologic studies (6-8 hours each) during pregnancy or postpartum. Participants were on a stable daily dose of 2-8 mg sublingual buprenorphine every 6 or 8 hours. The dosing frequency was selected by the participant. On study day, baseline measurements of plasma buprenorphine, pupil diameter, COWS, and craving scores were obtained, then the usual morning dose was taken, and measurements were repeated several times over 1 dosing interval.

FINDINGS

The dose-normalized area under the plasma buprenorphine concentration time curve was significantly (P = 0.036) lower during pregnancy (155 ± 52 ng × min/mL) than postpartum (218 ± 113 ng × min/mL). Buprenorphine trough concentrations were similar at the start (1.1 ± 0.7 ng/mL) and end of a dosing cycle (1.2 ± 0.8 ng/mL) regardless of dosing frequency. Pupillary diameter, COWS, and craving scores returned to baseline as buprenorphine concentrations approached ~1 ng/mL.

CONCLUSIONS

Pregnant people require a higher dose of buprenorphine to achieve concentrations comparable to nonpregnant people. There is a temporal relationship between the plasma buprenorphine concentration and the pharmacodynamic markers of pupillary diameter, COWS, and craving scores. An average plasma concentration of ~1 ng/mL was associated with the lowest level of COWS and craving scores.

Can umbilical cord testing add to maternal urine drug screen for evaluation of infants at risk of neonatal opioid withdrawal syndrome?

OBJECTIVE

This study evaluated maternal urine drug screen (UDS) at delivery and umbilical cord drug testing and its association with neonatal opioid withdrawal syndrome (NOWS) diagnosis and severity following opioid exposed pregnancy.

METHODS

A retrospective chart review of 770 mother-infant dyads at five birthing hospitals in the United States Appalachian region for a five-year period was performed. Variables of interest included dyad demographics, results of maternal UDS at delivery and umbilical cord drug testing, and three neonatal outcomes: NOWS diagnosis, pharmacologic treatment administered for NOWS, and length of hospital stay (LOS) of the newborn.

RESULTS

Opioid-positivity was between 8.5% and 66.3% based on maternal UDS at delivery or umbilical cord testing. Odds of NOWS diagnosis and increased infant LOS was best associated with opioid detection in maternal UDS alone (OR = 5.62, 95% CI [3.06, 10.33] and OR = 8.33, 95% CI [3.67, 18.89], respectively). However, odds of pharmacologic treatment for NOWS was best associated with opioid detection in both maternal UDS and umbilical cord testing on the same dyad (OR = 3.22, 95% CI [1.14, 9.09]).

CONCLUSION

Maternal UDS is a better option compared to umbilical cord testing for evaluation of opioid-exposed infants and risk of NOWS diagnosis and increased infant LOS.

An Examination of the Complex Pharmacological Properties of the Non-Selective Opioid Modulator Buprenorphine

The goal of this review is to provide a recent examination of the pharmacodynamics as well as pharmacokinetics, misuse potential, toxicology, and prenatal consequences of buprenorphine. Buprenorphine is currently a Schedule III opioid in the US used for opioid-use disorder (OUD) and as an analgesic. Buprenorphine has high affinity for the mu-opioid receptor (MOR), delta (DOR), and kappa (KOR) and intermediate affinity for the nociceptin (NOR). Buprenorphine's active metabolite, norbuprenorphine, crosses the blood-brain barrier, is a potent metabolite that attenuates the analgesic effects of buprenorphine due to binding to NOR, and is responsible for the respiratory depressant effects. The area under the concentration curves are very similar for buprenorphine and norbuprenorphine, which indicates that it is important to consider this metabolite. Crowding sourcing has identified a buprenorphine street value (USD 3.95/mg), indicating some non-medical use. There have also been eleven-thousand reports involving buprenorphine and minors (age < 19) at US poison control centers. Prenatal exposure to clinically relevant dosages in rats produces reductions in myelin and increases in depression-like behavior. In conclusion, the pharmacology of this OUD pharmacotherapy including the consequences of prenatal buprenorphine exposure in humans and experimental animals should continue to be carefully evaluated.

Assessing Neonatal Opioid Withdrawal Syndrome Severity as a Function of Maternal Buprenorphine Dose and Umbilical Cord Tissue Concentrations

BACKGROUND

Infants born to mothers with opioid use disorder (OUD) and prenatally treated with buprenorphine have a significantly lower incidence of neonatal opioid withdrawal syndrome (NOWS), its treatment duration, and hospital length of stay compared with methadone. However, risk of NOWS remains and clinicians continue to lack an objective methodology to predict NOWS severity among these infants.

OBJECTIVE

The purpose of this study was to assess the relationship between buprenorphine exposure, umbilical cord tissue (UCT) concentrations, and NOWS development and severity.

METHODS

A single-center retrospective observational cohort study from March 2018 through June 2020 of newborns exposed to buprenorphine in utero. Associations between quantified buprenorphine exposure, neonatal UCT concentrations, NOWS diagnosis, and severity were made using regression analyses.

RESULTS

A total of 24 mothers and 25 neonates were included. Length of maternal buprenorphine therapy (months) positively correlated to norbuprenorphine (r² = 0.234, P = 0.019) and buprenorphine + norbuprenorphine UCT concentrations (r² = 0.203, P = 0.031). A positive relationship was seen between active metabolite concentrations and cumulative morphine dose (mg/kg) for treatment of severe NOWS (r² = 0.471, P = 0.007). A 0.36 ng/g buprenorphine + norbuprenorphine UCT (CI = 0.002-0.72, P = 0.049) equated in a 1-point increase in modified peak Finnegan score.

CONCLUSION AND RELEVANCE

Buprenorphine and norbuprenorphine UCT concentrations can allow for quantification of in utero fetal exposure and demonstrate an association with a longer duration of exposure with the severity and treatment of NOWS in exposed infants.

Interaction between buprenorphine and norbuprenorphine in neonatal opioid withdrawal syndrome

Buprenorphine (BUP) is the preferred treatment for opioid use disorder during pregnancy but can cause neonatal opioid withdrawal syndrome (NOWS). Norbuprenorphine (NorBUP), an active metabolite of BUP, is implicated in BUP-associated NOWS. We hypothesized that BUP, a low-efficacy agonist of mu opioid receptors, will not antagonize NorBUP, a high-efficacy agonist of mu opioid receptors, in producing NOWS. To test this hypothesis, we treated pregnant Long-Evans rats with BUP (0, 0.01, 0.1 or 1mg/kg/day) ± NorBUP (1mg/kg/day) from gestation day 9 until pup delivery, and tested pups for opioid dependence using our established NOWS model. We used LC-MS-MS to quantify brain concentrations of BUP, NorBUP, and their glucuronide conjugates. BUP had little effect on NorBUP-induced NOWS, with the exception of 1mg/kg/day BUP significantly increasing NorBUP-induced NOWS by 58% in females. BUP and NorBUP brain concentrations predicted NOWS in multiple linear regression models. Interestingly, NorBUP contributed more to NOWS in females (βNorBUP = 51.34, p = 0.0001) than in males (βNorBUP = 19.21, P = 0.093), while BUP was similar for females (βBUP = 10.62, P = 0.0017) and males (βBUP = 11.38, P = 0.009). We are the first to report that NorBUP induces NOWS in the presence of BUP and it is more influential in females than males in the contribution of NorBUP to BUP-associated NOWS. These findings suggest that females are more susceptible to NorBUP-induced NOWS, and that treatment strategies that reduce prenatal NorBUP exposure may be more effective for females than males.

Deuterated buprenorphine retains pharmacodynamic properties of buprenorphine and resists metabolism to the active metabolite norbuprenorphine in rats

Introduction: An active metabolite of buprenorphine (BUP), called norbuprenorphine (NorBUP), is implicated in neonatal opioid withdrawal syndrome when BUP is taken during pregnancy. Therefore, reducing or eliminating metabolism of BUP to NorBUP is a novel strategy that will likely lower total fetal exposure to opioids and thus improve offspring outcomes. Precision deuteration alters pharmacokinetics of drugs without altering pharmacodynamics. Here, we report the synthesis and testing of deuterated buprenorphine (BUP-D2). Methods: We determined opioid receptor affinities of BUP-D2 relative to BUP with radioligand competition receptor binding assays, and the potency and efficacy of BUP-D2 relative to BUP to activate G-proteins via opioid receptors with [³⁵S]GTPγS binding assays in homogenates containing the human mu, delta, or kappa opioid receptors. The antinociceptive effects of BUP-D2 and BUP were compared using the warm-water tail withdrawal assay in rats. Blood concentration versus time profiles of BUP, BUP-D2, and NorBUP were measured in rats following intravenous BUP-D2 or BUP injection. Results: The synthesis provided a 48% yield and the product was ≥99% deuterated. Like BUP, BUP-D2 had sub-nanomolar affinity for opioid receptors. BUP-D2 also activated opioid receptors and induced antinociception with equal potency and efficacy as BUP. The maximum concentration and the area under the curve of NorBUP in the blood of rats that received BUP-D2 were over 19- and 10-fold lower, respectively, than in rats that received BUP. Discussion: These results indicate that BUP-D2 retains key pharmacodynamic properties of BUP and resists metabolism to NorBUP and therefore holds promise as an alternative to BUP.

Determination of Prenatal Substance Exposure Using Meconium and Orbitrap Mass Spectrometry

The aim of this study was to develop and to validate a toxicological untargeted screening relying on LC-HRMS in meconium including the detection of the four main classes of drugs of abuse (DoA; amphetamines, cannabinoids, opioids and cocaine). The method was then applied to 29 real samples. Analyses were performed with a liquid chromatography system coupled to a benchtop Orbitrap operating in a data-dependent analysis. The sample amount was 300 mg of meconium extracted twice by solid phase extraction following two distinct procedures. Raw data were processed using the Compound Discoverer 3.2 software (Thermo). The method was evaluated and validated on 15 compounds (6-MAM, morphine, buprenorphine, norbuprenorphine, methadone, EDDP, amphetamine, MDA, MDMA, methamphetamine, cocaine, benzoylecgonine, THC, 11-OH-THC, THC-COOH). Limits of detection were between 0.5 and 5 pg/mg and limits of identification between 5 and 50 pg/mg. Mean matrix effect was between −79 and −19% (n = 6) and mean overall recovery between 18 and 73% (n = 6) at 100 pg/mg. The application allows the detection of 88 substances, including 47 pharmaceuticals and 15 pharmaceutical metabolites, cocaine and its metabolites, THC and its metabolites, and natural (morphine, codeine) and synthetic (methadone, buprenorphine, tramadol, norfentanyl) opioids. This method is now used routinely for toxicological screening in high-risk pregnancies

Toxicology as a diagnostic tool to identify the misuse of drugs in the perinatal period

The use, misuse, and abuse of substances are a continued public health concern in this country and around the world. Perinatal exposure to substances of abuse is associated with several long-term negative consequences for the neonate. Limited resources exist to assist perinatal health professionals on this very complex subject. The purpose of this document is to provide additional information about selecting monitoring protocols, the specifics of appropriate testing methodologies, and the interpretation of toxicological findings. Understanding these concepts better allows perinatal healthcare professionals to be a voice for the voiceless in order to protect and enrich lives during this unprecedented opioid epidemic.

A review of pregnancy-induced changes in opioid pharmacokinetics, placental transfer, and fetal exposure: Towards fetomaternal physiologically-based pharmacokinetic modeling to improve the treatment of neonatal opioid withdrawal syndrome

Physiologically-based pharmacokinetic (PBPK) modeling has emerged as a useful tool to study pharmacokinetics (PK) in special populations, such as pregnant women, fetuses, and newborns, where practical hurdles severely limit the study of drug behavior. PK in pregnant women is variable and everchanging, differing greatly from that in their nonpregnant female and male counterparts typically enrolled in clinical trials. PBPK models can accommodate pregnancy-induced physiological and metabolic changes, thereby providing mechanistic insights into maternal drug disposition and fetal exposure. Fueled by the soaring opioid epidemic in the United States, opioid use during pregnancy continues to rise, leading to an increased incidence of neonatal opioid withdrawal syndrome (NOWS). The severity of NOWS is influenced by a complex interplay of extrinsic and intrinsic factors, and varies substantially between newborns, but the extent of prenatal opioid exposure is likely the primary driver. Fetomaternal PBPK modeling is an attractive approach to predict in utero opioid exposure. To facilitate the development of fetomaternal PBPK models of opioids, this review provides a detailed overview of pregnancy-induced changes affecting the PK of commonly used opioids during gestation. Moreover, the placental transfer of these opioids is described, along with their disposition in the fetus. Lastly, the implementation of these factors into PBPK models is discussed. Fetomaternal PBPK modeling of opioids is expected to provide improved insights in fetal opioid exposure, which allows for prediction of postnatal NOWS severity, thereby opening the way for precision postnatal treatment of these vulnerable infants.

Neonatal Outcomes after Combined Opioid and Nicotine Exposure in Utero: A Scoping Review

BACKGROUND

The majority of women who are pregnant with opioid use disorder (OUD) also smoke tobacco but are rarely offered tobacco cessation counseling. While the effects of exposure to opioids and nicotine in utero are well-understood separately, understanding the impact of the combined exposure to these substances on neonatal outcomes is lacking.

METHODS

A scoping review was conducted using PubMed and Scopus databases for studies addressing the combined exposure to opioids and nicotine during pregnancy published between 1 January 1980 and 9 July 2019. A total of 29 papers met the eligibility criteria for inclusion, with nine being identified as clinical trials (three from the MOTHER study) and two as secondary data analysis of clinical trial data.

RESULTS

Neonatal outcomes for infants who had a combined exposure to opioids and nicotine in utero indicated a reduction in birth weight and birth length. Findings in infants exposed to both nicotine and opioids were mixed with regard to the duration of neonatal abstinence syndrome (NAS), the likelihood of treatment for NAS, doses of medicine used to treat NAS, and NAS scores when compared with infants who had opioid exposure without nicotine.

CONCLUSIONS

The combined exposure to nicotine and opioids during pregnancy may lead to a reduction in neonatal birth weight and birth length and more severe NAS signs, compared with opioid use alone, but more research is necessary to identify the minimum dosage and length of nicotine exposure to accurately predict these outcomes.

Analysis of cannabinoids in conventional and alternative biological matrices by liquid chromatography: Applications and challenges

Cannabis is by far the most widely abused illicit drug globe wide. The analysis of its main psychoactive components in conventional and non-conventional biological matrices has recently gained a great attention in forensic toxicology. Literature states that its abuse causes neurocognitive impairment in the domains of attention and memory, possible macrostructural brain alterations and abnormalities of neural functioning. This suggests the necessity for the development of a sensitive and a reliable analytical method for the detection and quantification of cannabinoids in human biological specimens. In this review, we focus on a number of analytical methods that have, so far, been developed and validated, with particular attention to the new "golden standard" method of forensic analysis, liquid chromatography mass spectrometry or tandem mass spectrometry. In addition, this review provides an overview of the effective and selective methods used for the extraction and isolation of cannabinoids from (i) conventional matrices, such as blood, urine and oral fluid and (ii) alternative biological matrices, such as hair, cerumen and meconium.

Monitoring Prenatal Exposure to Buprenorphine and Methadone

PURPOSE

Buprenorphine and methadone are international gold standards for managing opioid use disorders. Although they are efficacious in treating opioid dependence, buprenorphine and methadone present risks, especially during pregnancy, causing neonatal abstinence syndrome and adverse obstetrical outcomes. Buprenorphine and methadone are also abused during pregnancy, and identifying their use is important to limit unprescribed prenatal exposure. Previous studies have suggested that concentrations of buprenorphine, but not methadone markers in unconventional matrices may predict child outcomes, although currently only limited data exist. We reviewed the literature on concentrations of buprenorphine, methadone, and their metabolites in unconventional matrices to improve data interpretation.

METHODS

A literature search was conducted using scientific databases (PubMed, Scopus, Web of Science, and reports from international institutions) to review published articles on buprenorphine and methadone monitoring during pregnancy.

RESULTS

Buprenorphine and methadone and their metabolites were quantified in the meconium, umbilical cord, placenta, and maternal and neonatal hair. Methadone concentrations in the meconium and hair were typically higher than those in other matrices, although the concentrations in the placenta and umbilical cord were more suitable for predicting neonatal outcomes. Buprenorphine concentrations were lower and required sensitive instrumentation, as measuring buprenorphine glucuronidated metabolites is critical to predict neonatal outcomes.

CONCLUSIONS

Unconventional matrices are good alternatives to conventional ones for monitoring drug exposure during pregnancy. However, data are currently scarce on buprenorphine and methadone during pregnancy to accurately interpret their concentrations. Clinical studies should be conducted with larger cohorts, considering confounding factors such as illicit drug co-exposure.

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.

Drug testing in biological samples vs. maternal surveys for the detection of substance use during whole pregnancy

BACKGROUND

Early diagnosis of nicotine, ethanol and drug use during pregnancy is critical in order to provide adequate care. Current screening procedures show limitations in terms of reliability and short windows of detection.

OBJECTIVES

To investigate the prevalence and identify biomarkers of substance use and changes in substance use during pregnancy. To compare drug testing results in different types of biological samples (maternal hair, meconium, placenta, umbilical-cord) with self-reported data.

PARTICIPANTS AND SETTING

Prospective cohort study using data from pregnant women and their newborns.

METHODS

Biological matrices were collected at birth and analyzed by liquid chromatography tandem mass spectrometry. A paper survey was provided to determine substance use habits.

RESULTS

867 mother-newborn pairs were included. According to the analysis of biological samples, 29.1% cases were positive for one or more substances (13.6% nicotine, 8.4% ethanol, 8.3% cocaine, 6.4% cannabis, 5.7% opioids). The profile of the substance-using mother was a single woman, <28 years-old, with no higher education and unemployed. Segmental maternal hair analysis showed a decrease in tobacco, cannabis and cocaine use throughout pregnancy (p < 0.001). The level of concordance between results from interviews and from biological analyses was weak for opioids, cocaine, and cannabis (kappa coefficient < 0.40). Maternal hair detected the highest number of cases, followed by meconium and by placenta and/or umbilical-cord.

CONCLUSIONS

Maternal survey was not a reliable screening technique. Analysis of maternal hair detected the highest number of cases with the broadest detection window (whole pregnancy).

Buprenorphine dosing for the treatment of opioid use disorder through pregnancy and postpartum

PURPOSE OF REVIEW

Opioid-related deaths are a leading cause of mortality during pregnancy through 12 months postpartum. Buprenorphine use during pregnancy is increasing, yet expert opinion on its dosing through the perinatal period is limited. We provide a review of the current clinical literature on buprenorphine dosing during pregnancy through 12 months postpartum. and present data from a retrospective chart review of patients at our institution describing trends in buprenorphine dosing during pregnancy and postpartum. Utilizing this information, we synthesize findings to provide clinical recommendations for providers.

RECENT FINDINGS

Existing literature during pregnancy reflects how many women increase and split total daily buprenorphine doses as gestational age advances.

SUMMARY

We present data from a retrospective chart review of patients at our institution describing trends in buprenorphine dosing during pregnancy and postpartum. Utilizing this information, we synthesize findings to provide clinical recommendations for providers. Changes in the total daily dose of buprenorphine used across pregnancy and through 12 months postpartum at the individual level do not follow consistent patterns, highlighting substantial individual variability. Altogether, buprenorphine dosing should be individualized through pregnancy and postpartum with frequent evaluations by providers and solicited input from patients.

The role of xenobiotic-metabolizing enzymes in the placenta: a growing research field

Introduction: The placenta is a temporary and unique organ that allows for the physical connection between a mother and fetus; this organ regulates the transport of gases and nutrients mediating the elimination of waste products contained in the fetal circulation. The placenta performs metabolic and excretion functions, on the basis of multiple enzymatic systems responsible for the oxidation, reduction, hydrolysis, and conjugation of xenobiotics. These mechanisms give the placenta a protective role that limits the fetal exposure to harmful compounds. During pregnancy, some diseases require uninterrupted treatment even if it is detrimental to the fetus. Drugs and other xenobiotics alter gene expression in the placenta with repercussions for the fetus and mother's well-being.Areas covered: This review provides a brief description of the human placental structure and function, the main drug and xenobiotic transporters and metabolizing enzymes, placenta-metabolized substrates, and alterations in gene expression that the exposure to xenobiotics may cause.Expert opinion: Research should be focused on the identification and validation of biological markers for the assessment of the harmful effects of some drugs in pregnancy, including the evaluation of polymorphisms and methylation patterns in chorionic villous samples and/or amniotic fluid.

Delivery dose of methadone, but not buprenorphine, is associated with the risk and severity of neonatal opiate withdrawal syndrome

BACKGROUND

Data on the relationship between the dose of opioid replacement therapy in pregnancy and the risk and severity of neonatal opioid withdrawal syndrome are conflicting and have methodological limitations.

OBJECTIVE

To assess the association of methadone and buprenorphine dose at delivery with neonatal opioid withdrawal syndrome in a large cohort.

STUDY DESIGN

We performed a retrospective cohort study using data from a comprehensive perinatal opioid dependency program from 2000 through 2016. Women with a history of opioid use disorder enrolled in a medication-assisted treatment program were included. Strict neonatal opioid withdrawal syndrome case definition and neonatal treatment guidelines were utilized throughout the study epoch. Comparisons were made between women on methadone and buprenorphine. The dose of opioid replacement at delivery and the risk and severity of neonatal opioid withdrawal syndrome were assessed with univariable analysis and multivariable logistic regression. In all analyses, methadone and buprenorphine dosing were evaluated as a continuous variable.

RESULTS

Four hundred eighty two of 709 women (68.0%) met inclusion criteria including 344 on methadone (71.4%) and 138 on buprenorphine (28.6%). Nonopioid polysubstance abuse, body mass index, medication-assisted treatment compliance, birthweight, and other characteristics were similar between groups. Overall, the frequency of neonatal opioid withdrawal syndrome was not significantly different between the methadone and buprenorphine groups (56.8% vs 52.0%, P = .35). Dose at delivery ranged at 0-165 mg for methadone and 0-30 mg for buprenorphine. In a univariable analysis, methadone dose at delivery was associated with neonatal opioid withdrawal syndrome (83.0 ± 34.2 mg vs 71.9 ± 35.8 mg for neonatal opioid withdrawal syndrome vs nonneonatal opioid withdrawal syndrome neonates, P < .001), but buprenorphine dose at delivery was not (8.4 ± 4.4 vs 7.6 ± 4.8 mg for neonatal opioid withdrawal syndrome vs nonneonatal opioid withdrawal syndrome neonates, P = .30). Peak neonatal opioid withdrawal syndrome score, duration of neonatal opioid withdrawal syndrome treatment, and cumulative neonatal morphine exposure were significantly associated with delivery methadone dose but not buprenorphine dose. The association between delivery methadone dose and neonatal opioid withdrawal syndrome persisted in multivariable regression.

CONCLUSION

The dose of methadone at the time of delivery is associated with the frequency and severity of neonatal opioid withdrawal syndrome, with higher doses associated with more severe neonatal opioid withdrawal syndrome when analyzed continuously. These data may inform future prospective studies on methadone dosing in pregnancy. While medication-assisted treatment agent and dose may have an impact on pertinent neonatal outcomes related to neonatal opioid withdrawal syndrome, the provision of medication-assisted treatment in pregnancy should reflect the goal of prevention of recidivism and maternal mortality and utilize an approach that balances fetal and maternal risk to optimize outcomes.

Opioids affect the fetal brain: reframing the detoxification debate

Medication-assisted treatment is recommended for individuals with an opioid use disorder, including pregnant women. Medication-assisted treatment during pregnancy provides benefits to the mother and fetus, including better pregnancy outcomes, reduced illicit drug use, and improved prenatal care. An alternative approach, medically supervised withdrawal (detoxification), has, in recent reports, demonstrated a low risk of fetal death and low rates of relapse and neonatal abstinence syndrome. The rates of relapse and neonatal abstinence syndrome are questioned by many who view medically supervised withdrawal as unacceptable based on the concern for the potential adverse consequences of relapse to mother and baby. The impact of opioids on the fetal brain have not been integrated into this debate. Studies in animals and human brain tissues demonstrate opioid receptors in neurons, astroglia, and oligodendrocytes. Age-specific normative data from infants, children, and adults have facilitated investigation of the impact of opioids on the human brain in vivo. Collectively, these studies in animals, human neural tissue, adult brains, and the brains of children and newborns demonstrate that opioids adversely affect the human brain, primarily the developing oligodendrocyte and the processes of myelinization (white matter microstructure), connectivity between parts of the brain, and the size of multiple brain regions, including the basal ganglia, thalamus, and cerebellar white matter. These in vivo studies across the human lifespan suggest vulnerability of specific fronto-temporal-limbic and frontal-subcortical (basal ganglia and cerebellum) pathways that are also likely vulnerable in the human fetal brain. The long-term impact of these reproducible changes in the fetal brain in vivo is unclear, but the possibility of lasting injury has been suggested. In light of the recent data on medically supervised withdrawal and the emerging evidence suggesting adverse effects of opioids on the developing fetal brain, a new paradigm of care is needed that includes the preferred option of medication-assisted treatment but also the option of medically supervised opioid withdrawal for a select group of women. Both these treatment options should offer mental health and social services support throughout pregnancy. More research on both opioid exposure on the developing human brain and the impact of medically supervised withdrawal is required to identify appropriate candidates, optimal dose reduction regimens, and gestational age timing for initiating medically supervised withdrawal.

Quantifying fetal alcohol exposure by meconium fatty acid ethyl esters (FAEE); association with adverse fetal outcomes and population estimates of fetal alcohol exposure

Fetal Alcohol Spectrum Disorder (FASD) describes the wide range of adverse physical, behavioral and cognitive effects resulting from ethanol exposure during embryonic and fetal development. Identification of children suffering from FASD is often difficult, as abuse of ethanol during pregnancy is a heavily stigmatized behavior that receives little prenatal screening attention in routine care. Over the last 3 decades, measurement of the ethanol metabolites fatty acid ethyl esters (FAEE) has emerged as a useful tool to detect in the neonatal period fetal alcohol exposure starting from mid gestation. This review aims at updating clinicians and researchers on the validity and utility of this biological marker in two aspects: The association with adverse fetal outcomes and in generating population estimates of fetal alcohol exposure.

Pregnancy Increases Norbuprenorphine Clearance in Mice by Induction of Hepatic Glucuronidation

Norbuprenorphine (NBUP) is the major active metabolite of buprenorphine (BUP) that is commonly used to treat opiate addiction during pregnancy; it possesses 25% of BUP's analgesic activity and 10 times BUP's respiratory depression effect. To optimize BUP's dosing regimen during pregnancy with better efficacy and safety, it is important to understand how pregnancy affects NBUP disposition. In this study, we examined the pharmacokinetics of NBUP in pregnant and nonpregnant mice by administering the same amount of NBUP through retro-orbital injection. We demonstrated that the systemic clearance (CL) of NBUP in pregnant mice increased ∼2.5-fold compared with nonpregnant mice. Intrinsic CL of NBUP by glucuronidation in mouse liver microsomes from pregnant mice was ∼2 times greater than that from nonpregnant mice. Targeted liquid chromatography tandem-mass spectrometry proteomics quantification revealed that hepatic Ugt1a1 and Ugt2b1 protein levels in the same amount of total liver membrane proteins were significantly increased by ∼50% in pregnant mice versus nonpregnant mice. After scaling to the whole liver with consideration of the increase in liver protein content and liver weight, we found that the amounts of Ugt1a1, Ugt1a10, Ugt2b1, and Ugt2b35 protein in the whole liver of pregnant mice were significantly increased ∼2-fold compared with nonpregnant mice. These data suggest that the increased systemic CL of NBUP in pregnant mice is likely caused by an induction of hepatic Ugt expression and activity. The data provide a basis for further mechanistic analysis of pregnancy-induced changes in the disposition of NBUP and drugs that are predominately and extensively metabolized by Ugts.

Maternal buprenorphine treatment and infant outcome

BACKGROUND AND OBJECTIVES

Maternal buprenorphine maintenance predisposes the infant to exhibit neonatal abstinence syndrome (NAS), but there is insufficient published information regarding the nature of NAS and factors that contribute to its severity in buprenorphine-exposed infants.

METHODS

The present study evaluated forty-one infants of buprenorphine-maintained women in comprehensive substance use disorder treatment who participated in an open-label study examining the effects of maternal buprenorphine maintenance on infant outcomes. Modifiers of the infant outcomes, including maternal treatment and substance use disorder parameters, were also evaluated.

RESULTS

Fifty-nine percent of offspring exhibited NAS that required pharmacologic management. Both maternal buprenorphine dose as well as prenatal polysubstance exposure to illicit substance use/licit substance misuse were independently associated with NAS expression. Polysubstance exposure was associated with more severe NAS expression after controlling for the effects of buprenorphine dose. Other exposures, including cigarette smoking and SRI use, were not related to outcomes. Maternal buprenorphine dose was positively associated with lower birth weight and length.

CONCLUSIONS

Polysubstance exposure was the most potent predictor of NAS severity in this sample of buprenorphine-exposed neonates. This finding suggests the need for interventions that reduce maternal polysubstance use during medication assisted treatment for opioid use disorder, and highlights the necessity of a comprehensive approach, beyond buprenorphine treatment alone, for the optimal care for pregnant women with opioid use disorders.

An evidence-based recommendation to increase the dosing frequency of buprenorphine during pregnancy

BACKGROUND

Dose-adjusted plasma concentrations of buprenorphine are significantly decreased during pregnancy compared with the nonpregnant state. This observation suggests that pregnant women may need a higher dose of buprenorphine than nonpregnant individuals to maintain similar drug exposure (plasma concentrations over time after a dose). The current dosing recommendations for buprenorphine during pregnancy address the total daily dose of buprenorphine to be administered, but the frequency of dosing is not clearly addressed. Based on buprenorphine's long terminal half-life, once-daily or twice-daily dosing has generally been suggested.

OBJECTIVE

The objective of the study was to assess the impact of dosing frequency on buprenorphine plasma concentration time course during pregnancy.

STUDY DESIGN

We utilized 3 data sources to determine an optimal frequency for dosing of buprenorphine during pregnancy: data from a pharmacokinetic study of 14 pregnant and postpartum women on maintenance buprenorphine in a supervised clinical setting; data from pregnant women attending a buprenorphine clinic; and data from a physiologically based pharmacokinetic modeling of buprenorphine pharmacokinetics in nonpregnant subjects.

RESULTS

Among the 14 women participating in the pharmacokinetic study during and after pregnancy, plasma concentrations of buprenorphine were <1 ng/mL (the theoretical concentration required to prevent withdrawal symptoms) for 50-80% of the 12 hour dosing interval while at steady state. Among 62 women followed up in a opioid agonist treatment program, in which dosing frequency is determined in part by patient preference, 10 (16%) were on once-daily dosing, 10 (16%) were on twice-daily dosing, 28 (45%) were on thrice-daily dosing, and 14 (23%) were on four-times-daily dosing. A physiologically based pharmacokinetic model in nonpregnant subjects demonstrated that dosing frequency has an impact on the duration over which the plasma concentrations are below a specified plasma concentration threshold.

CONCLUSION

A more frequent dosing interval (ie, three-times-daily or four-times-daily dosing) may be required in pregnant women to sustain plasma concentrations above the threshold of 1 ng/mL to prevent withdrawal symptoms and to improve adherence.

Buprenorphine for Medication-Assisted Treatment of Opioid Use Disorder in Pregnancy: Relationship to Neonatal Opioid Withdrawal Syndrome

Objective  To examine the relationship between antepartum buprenorphine dose for medication-assisted treatment (MAT) of opioid use disorder (OUD) and incident neonatal opioid withdrawal syndrome (NOWS). Study Design  We performed a prospective cohort study of pregnant women with a singleton gestation diagnosed with OUD and receiving buprenorphine for MAT at a tertiary care academic institution from July 2015 to January 2017. We divided the study cohort into two groups-pregnancies with versus without NOWS. Substance abuse patterns in pregnancy, maternal, and neonatal clinical outcomes were compared. Results  The incidence of NOWS was 31.11% ( n  = 28/90) in our study cohort. Pregnancies with NOWS had a significantly higher rate of benzodiazepine positive urine tests and number of positive urine drug screen (UDS) results for illicit opioids. The group without NOWS had significantly higher number of patients with an appropriate UDS result at delivery through postpartum. Rates of neonatal intensive care unit (NICU) admission, length of NICU stay, and maximum Finnegan score were significantly higher in the group with NOWS. Neither the initial (10.6 ± 5.2 versus 10.3 ± 4.8 mg, p  = 0.80) nor the final buprenorphine doses (13.3 ± 5.1 versus 13.0 ± 4.6 mg, p  = 0.81) were significantly different between study groups. Conclusion  The occurrence of NOWS was not related to buprenorphine dose used for MAT.

Maternal Buprenorphine Maintenance and Lactation

BACKGROUND

In addition to the well-known benefits of human milk and breastfeeding for the mother and infant, breastfeeding may mitigate neonatal abstinence syndrome severity in prenatally opioid-exposed infants. However, lack of conclusive data regarding the extent of the presence of buprenorphine and active metabolites in human milk makes the recommendation of breastfeeding for buprenorphine-maintained women difficult for many providers.

OBJECTIVE

This study seeks to determine the concentrations of buprenorphine and its active metabolites (norbuprenorphine, buprenorphine-glucuronide, and norbuprenorphine-glucuronide) in human milk, maternal plasma, and infant plasma of buprenorphine-maintained women and their infants.

METHODS

Up to 10 buprenorphine-maintained women provided paired breast milk and plasma samples at 2, 3, 4, 14, and 30 days postdelivery, and 9 infants provided plasma samples on day 14 of life. All samples were analyzed via liquid chromatography tandem mass spectrometry to determine concentrations of buprenorphine, norbuprenorphine, buprenorphine-glucuronide, and norbuprenorphine-glucuronide by a fully validated method.

RESULTS

Concentrations of buprenorphine and metabolites are low in human milk and maternal plasma. Breastfed infant plasma concentrations of buprenorphine were low or undetectable and metabolite concentrations undetectable at 14 days of infant age. There were significant correlations between maternal buprenorphine dose and maternal plasma and human milk buprenorphine concentrations.

CONCLUSION

These data find low concentrations of buprenorphine and metabolites in human milk and lend support to the recommendation for lactation among stable buprenorphine-maintained women. However, the correlation between maternal dose and maternal plasma and human milk buprenorphine concentrations bears further study.

Predictors of neonatal abstinence syndrome in buprenorphine exposed newborn: can cord blood buprenorphine metabolite levels help?

BACKGROUND

Buprenorphine is a semi-synthetic opioid used for the treatment of opioid dependence. Opioid use, including buprenorphine, has been increasing in recent years, in the general population and in pregnant women. Consequently, there has been a rise in frequency of neonatal abstinence syndrome (NAS), associated with buprenorphine use during pregnancy. The purpose of this study was to investigate correlations between buprenorphine and buprenorphine-metabolite concentrations in cord blood and onset of NAS in buprenorphine exposed newborns.

METHODS

Nineteen (19) newborns who met inclusion criteria were followed after birth until discharge in a double-blind non-intervention study, after maternal consent. Cord blood and tissue samples were collected and analyzed by liquid chromatography-mass spectrometry (LC-MS) for buprenorphine and metabolites. Simple and multiple logistic regressions were used to examine relationships between buprenorphine and buprenorphine metabolite concentrations in cord blood and onset of NAS, need for morphine therapy, and length of stay.

RESULTS

Each increase in 5 ng/ml level of norbuprenorphine in cord blood increases odds of requiring treatment by morphine 2.5 times. Each increase in 5 ng/ml of buprenorphine-glucuronide decreases odds of receiving morphine by 57.7 %. Along with concentration of buprenorphine metabolites, birth weight and gestational age also play important roles, but not maternal buprenorphine dose.

CONCLUSIONS

LC-MS analysis of cord blood concentrations of buprenorphine and metabolites is an effective way to examine drug and metabolite levels in the infant at birth. Cord blood concentrations of the active norbuprenorphine metabolite and the inactive buprenorphine-glucuronide metabolite show promise in predicting necessity of treatment of NAS. These finding have implications in improving patient care and reducing healthcare costs if confirmed in a larger sample.

Monitoring neonatal abstinence syndrome in buprenorphine-exposed in vitro fertilization twins: A case study

BACKGROUND

Prior studies have reported on the pregnancies and outcomes of in vitro fertilization (IVF) in special subpopulations; however, there is a lack of studies on opioid-exposed IVF-conceived neonates.

CASE PRESENTATION

A young adult IVF-pregnant woman was maintained on buprenorphine throughout pregnancy and received follow-up from the addiction clinic from estimated gestational week 32. She delivered healthy dichorionic twins via cesarean section at 38 weeks gestational age (buprenorphine dose at time of delivery: 16 mg). All maternal supervised urinalysis taken as of gestational week 32 were negative for concomitant substances (prior to treatment initiation at the addiction clinic, only self-reports of abstinence from concomitant substances were available). Both healthy children (male birth weight: 3140 g, female birth weight: 2650 g) developed an unusual course of neonatal abstinence syndrome (NAS) requiring extensive treatment (total morphine dose male: 22 mg, and female: 26.75 mg; length of treatment: 33 and 34 days, respectively; duration of hospitalization: 40 days).

DISCUSSION

The highly severe and long-lasting NAS in both neonates represents a very unusual course following an uneventful pregnancy, and influencing iatrogenic factors cannot be ruled out. Given the multiple variables influencing infant outcomes, this highlights the importance of high-quality, evidence-based standard operating procedures, which (1) are initiated as early as possible during pregnancy to minimize risk factors for adverse infant outcomes, such as concomitant substance use during pregnancy; (2) support the substance-dependent woman throughout the postpartum period, especially in cases of multiple and/or IVF-conceived pregnancies, where additional challenges may arise; and (3) consider the right of everyone to the enjoyment of the highest attainable standard of physical and mental health.

Quantitation of Total Buprenorphine and Norbuprenorphine in Meconium by LC-MS/MS

Buprenorphine (Suboxone, Zubsolv, Buprenex, Butrans, etc.) is an opioid drug that has been used to treat opioid dependence on an outpatient basis, and is also prescribed for managing moderate to severe pain. Pregnant women may be prescribed buprenorphine as part of a treatment plan for opioid addiction. This chapter quantitates buprenorphine and norbuprenorphine in meconium by liquid chromatography tandem mass spectrometry (LC-MS/MS).

Bioanalysis during pregnancy: recent advances and novel sampling strategies

Consumption of drugs of abuse, tobacco and alcohol throughout pregnancy is a serious public health problem and results in an important economic cost to the health system. Drug and/or metabolites determination in biological matrices from mother and newborn is an objective measure of in utero drug exposure. We reviewed methods published for the determination of in utero drug exposure from 2007 to 2014, with special focus on meconium, placenta, umbilical cord and newborn hair. Accurate bioanalytical procedures are essential to obtain high-quality data to perform interventions and to establish correlations between analytical measures and clinical outcomes. We included a brief overview of clinical implications of in utero drug exposure to better understand the importance of this serious health issue.

Meconium Tenofovir Concentrations and Growth and Bone Outcomes in Prenatally Tenofovir Exposed HIV-Uninfected Children

BACKGROUND

Maternal tenofovir disoproxil fumarate (TDF) treatment among HIV-infected pregnant women results in fetal tenofovir (TFV) exposure. Fetal TFV toxicity was demonstrated in animals, but most clinical investigations have not observed toxicity in humans.

METHODS

We evaluated HIV-exposed, uninfected infants in the Surveillance Monitoring for Antiretroviral Therapy Toxicities cohort of the Pediatric HIV/AIDS Cohort Study whose mothers were prescribed TDF for ≥ 8 third trimester weeks. Infant dual-energy X-ray absorptiometry scans were obtained at 0-4 weeks to measure whole body bone mineral content. Meconium TFV concentrations were quantified by liquid chromatography-tandem mass spectrometry.

RESULTS

Fifty-eight TFV-exposed infants had meconium TFV quantified. Detectable concentrations were 11-48,100 ng/g; 3 infants had undetectable concentrations. Maternal TDF prescription duration ranged from 8 to 41 gestational weeks; infant gestational ages were 36-41 weeks. Meconium TFV concentrations were not correlated with TFV exposure duration or timing and did not vary by concomitant prescription of protease inhibitors. Increased meconium TFV concentrations were associated with greater gestational ages (ρ = 0.29, P = 0.03) and lower maternal plasma HIV RNA before delivery (ρ = -0.29, P = 0.04). Meconium TFV concentrations were not associated with infant weight, length (n = 58) or bone mineral content (n = 49).

CONCLUSIONS

For the first time, we explored associations between meconium TFV concentrations and infant growth and bone measurements; we did not observe a meconium concentration-dependent relationship for these infant outcomes. These findings support other clinical research failing to show dose-response relationships for growth and bone outcomes among intrauterine TFV-exposed infants. High meconium TFV concentrations correlated with low maternal viral load, suggesting maternal TDF adherence significantly contributes to meconium TFV concentrations.

Antiretroviral Drugs in Meconium: Detection for Different Gestational Periods of Exposure

OBJECTIVES

To determine whether antiretroviral (ARV) medications can be detected in meconium from second or third trimester, labor and delivery (L&D), or postnatal exposures.

STUDY DESIGN

Twenty ARV medications were quantified by liquid chromatography-tandem mass spectrometry in 598 meconium samples from uninfected infants born to pregnant women with HIV enrolled in the Pediatric HIV/AIDS Cohort Study.

RESULTS

ARV detection in meconium following third trimester exposure was 85.7%-94.4% for all ARVs except stavudine (0%, n = 2), likely because of low doses and a high limit for quantification. Of 107 samples with some second trimester only ARV exposures, meconium was positive for only lopinavir, tenofovir, or efavirenz in 11.8%-14.3% of exposed neonates; administration of these ARVs occurred between gestational weeks 25-28 in the positive samples. Days without lopinavir or tenofovir before delivery significantly correlated with decreasing concentrations of lopinavir and tenofovir in meconium. Tenofovir and lamivudine concentrations significantly correlated with increasing gestational age among infants with continuous second and third trimester exposure. Zidovudine given during L&D or for neonatal prophylaxis was detected in 95.1% and 94.6% of meconium samples, respectively.

CONCLUSIONS

Changes in ARV treatments during pregnancy offered a unique opportunity to investigate ARV detection in meconium. ARVs in meconium primarily reflect third trimester ARV exposures, although 6 of 107 second trimester only exposures were detected. Zidovudine administration during L&D was detected in meconium indicating potential urine contamination or rapid incorporation into meconium. These data will improve interpretation of meconium drug test results.

Impact of lifetime opioid exposure on arterial stiffness and vascular age: cross-sectional and longitudinal studies in men and women

OBJECTIVE

To characterise and compare the potentiation of arterial stiffness and vascular ageing by opioids in men and women.

DESIGN

Cross-sectional and longitudinal studies of 576 clinical controls and 687 opioid-dependent patients (ODP) on 710 and 1305 occasions, respectively, over a total of 2382 days (6.52 years), 2006-2011. Methodology Radial pulse wave analysis with Atcor SphygmoCor system (Sydney).

SETTING

Primary care.

CONTROLS

General practice patients with non-cardiovascular disorders, and university student controls. ODP: Patients undergoing clinical management of their opioid dependence. CONTROLS had lower chronological ages (CAs) than ODP (30.0±0.5 vs 34.5±0.3, mean±SEM, p<0.0001). 69.6% and 67.7% participants were men, and 16% and 92.3% were smokers (p<0.0001) for controls and ODP, respectively. 86.3%, 10.3% and 3.4% of ODP were treated with buprenorphine (6.98±0.21 mg), methadone (63.04±4.01 mg) or implant naltrexone, respectively. Body mass index (BMI) was depressed in ODP.

INTERVENTIONS

Nil.

PRIMARY OUTCOME MEASURES

Vascular Reference Age (RA) and the ratio of vascular age to chronological age (RA/CA).

SECONDARY OUTCOME MEASURES

Arterial stiffness including Augmentation Index.

RESULTS

After BMI adjustment, RA in ODP was higher as a function of CA and of time (both p<0.05). Modelled mean RA in control and ODP was 35.6 and 36.3 years (+1.97%) in men, and 34.5 and 39.2 years (+13.43%) in women, respectively. Changes in RA and major arterial stiffness indices were worse in women both as a factor (p = 0.0036) and in interaction with CA (p = 0.0040). Quadratic, cubic and quartic functions of opioid exposure duration outperformed linear models with RA/CA over CA and over time. The opioid dose-response relationship persisted longitudinally after multiple adjustments from p=0.0013 in men and p=0.0073 in women.

CONCLUSIONS

Data show that lifetime opioid exposure, an interactive cardiovascular risk factor, particularly in women, is related to linear, quadratic, cubic and quartic functions of treatment duration and is consistent with other literature of accelerated ageing in patients with OD.

Incidence of prenatal alcohol exposure in Prince Edward Island: a population-based descriptive study

BACKGROUND

Fetal alcohol spectrum disorder (FASD) is a leading preventable cause of neurodevelopmental disability in North America. The stigma associated with alcohol use and abuse during pregnancy makes it difficult to obtain information on prenatal alcohol use through self-reporting. We assessed the incidence of prenatal alcohol exposure in Prince Edward Island to facilitate future public health initiatives addressing FASD.

METHODS

Prenatal alcohol exposure was examined via population-based collection of meconium and analysis of fatty acid ethyl esters (FAEEs). Fatty acid ethyl esters are nonoxidative metabolites of ethanol that are produced in the fetus. Meconium FAEE concentrations of 2.0 nmol/g or greater are indicative of frequent prenatal alcohol exposure during the last 2 trimesters of pregnancy. Samples were collected from 1307 neonates between Nov. 8, 2010, and Nov. 8, 2011, in hospitals in PEI, or from those born to mothers who resided in PEI but gave birth in Halifax, Nova Scotia. Samples were frozen and shipped for analysis. Fatty acid ethyl esters were analyzed by gas chromatography-mass spectrometry and quantified by means of deuterated internal standards.

RESULTS

Of the 1307 samples collected, 1271 samples were successfully analyzed. Positive results for FAEEs were obtained in 3.1% (n = 39) of samples collected within the first 24 hours after birth.

INTERPRETATION

Not all neonates exposed to heavy prenatal alcohol in utero will exhibit FASD; based on current estimates of predictive value for disease by exposure, our findings suggest that 1.3% of neonates born in PEI during this 1-year period will have FASD. In its application to an entire provincial birth cohort, this study successfully implemented a public health-centred approach for evaluating population-based risk of FASD, with implications for practice across Canada.

Alternative matrices for cocaine, heroin, and methadone in utero drug exposure detection

INTRODUCTION

Drug determination in biological matrices from the mother and the newborn is an objective measure of maternal and fetal drug exposure. The aim of this study was to compare maternal hair, meconium, umbilical cord, and placenta for detecting in utero drug exposure to cocaine, opiates, methadone, and amphetamines.

METHOD

Maternal hair, meconium, umbilical cord, and placenta were collected from 175 mother-newborn dyads. Maternal hair (segmented in trimesters) and meconium specimens were analyzed for cocaine, opiates, methadone, and amphetamines. If either maternal hair or meconium tested positive, umbilical cord and placenta were analyzed. Analyses were performed by liquid chromatography tandem mass spectrometry.

RESULTS

In hair, 24 participants tested positive; 21 for cocaine [cocaine 20-50,605, benzoylecgonine (BE) 17-46,668 pg/mg], 7 for methadone (76-26,845 pg/mg), 2 for opiates (morphine 298-2398 pg/mg, codeine 65-914 pg/mg, 6-acetylmorphine 1635-15,657 pg/mg), and 1 for amphetamines (amphetamine 1990 pg/mg, 3,4-methylenedioxyamphetamine 30 pg/mg, 3,4-methylenedioxymethamphetamine 294 pg/mg). In meconium, 6 were positive; 5 for methadone [methadone 88-3752, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) 642-25,179 ng/g], 3 for cocaine (cocaine 7, BE 79, hydroxybenzoylecgonine 5-135, ecgonine-methyl ester 2-56 ng/g), and 2 for opiates (morphine 152-1025, morphine-3-glucuronide 22-23, codeine 4-34 ng/g). Placenta and umbilical cord were positive in 5 and 6 cases, respectively; 5 for methadone in placenta (methadone 7-543, EDDP 10-51 ng/g) and cord (methadone 3-183, EDDP 2-109 ng/g); 1 for cocaine in placenta (cocaine 7, BE 2 ng/g) and cord (BE 6 ng/g); and 1 for opiates in placenta (morphine 6, morphine-3-glucuronide 48 ng/g), and 2 in cord (morphine 2, morphine-3-glucuronide 15-38, morphine-6-glucuronide 5 ng/g). Meconium, placenta, and umbilical cord only tested positive if hair concentrations were greater than Society of Hair Testing cutoffs.

CONCLUSIONS

Maternal hair is the most sensitive specimen to detect drug consumption during pregnancy. Placenta and umbilical cord could be alternatives to meconium for detecting high in utero drug exposure.

Neonatal outcomes and their relationship to maternal buprenorphine dose during pregnancy

BACKGROUND

Buprenorphine pharmacotherapy for opioid-dependent pregnant women is associated with maternal and neonatal outcomes superior to untreated opioid dependence. However, the literature is inconsistent regarding the possible existence of a dose-response relationship between maternal buprenorphine dose and neonatal clinical outcomes.

METHODS

The present secondary analysis study (1) examined the relationship between maternal buprenorphine dose at delivery and neonatal abstinence syndrome (NAS) peak score, estimated gestational age at delivery, Apgar scores at 1 and 5 min, neonatal head circumference, length, and weight at birth, amount of morphine needed to treat NAS, duration of NAS treatment, and duration of neonatal hospital stay and (2) compared neonates who required pharmacotherapy for NAS to neonates who did not require such pharmacotherapy on these same outcomes, in 58 opioid-dependent pregnant women receiving buprenorphine as participants in a randomized clinical trial.

RESULTS

(1) Analyses failed to provide evidence of a relationship between maternal buprenorphine dose at delivery and any of the 10 outcomes (all p-values>.48) and (2) significant mean differences between the untreated (n=31) and treated (n=27) for NAS groups were found for duration of neonatal hospital stay and NAS peak score (both p-values<.001).

CONCLUSIONS

(1) Findings failed to support the existence of a dose-response relationship between maternal buprenorphine dose at delivery and any of 10 neonatal clinical outcomes, including NAS severity and (2) that infants treated for NAS had a higher mean NAS peak score and, spent a longer time in the hospital than did the group not treated for NAS is unsurprising.

Rates of fetal polydrug exposures in methadone-maintained pregnancies from a high-risk population

Methadone maintenance treatment (MMT) is the standard of care during pregnancy for opioid-dependency, showing efficacy in improving prenatal care and reducing risk of relapse. By design, however, MMT is only intended to prevent withdrawal thus facilitating cognitive behavioural interventions. In order to maximize the benefits of MMT, it is essential that methadone is both properly prescribed and that additional addiction treatment is concurrently administered. This study aims to determine the effectiveness of MMT engagement in high-risk pregnant women in reducing polydrug use by objective laboratory examination of neonatal meconium.

Prenatal tobacco exposure, biomarkers for tobacco in meconium, and neonatal growth outcomes

OBJECTIVE

To assess relationships between marker concentrations of tobacco in meconium and weekly self-reported maternal cigarette consumption, and prediction of neonatal growth outcomes.

STUDY DESIGN

Pregnant mothers (n = 119) from a longitudinal maternal smoking and infant neurobehavioral study (Behavior and Mood in Babies and Mothers [BAM BAM]) provided daily tobacco smoking histories. Nicotine, cotinine, and trans-3'-hydroxycotinine concentrations were quantified in 111 neonatal meconium specimens by liquid chromatography-tandem mass spectrometry.

RESULTS

Median self-reported third trimester smoking was 5.9 cigarettes per day among smokers. Meconium samples from infants born to non-smokers (n = 42) were negative for tobacco markers, while specimens from self-reported smokers (n = 41) were positive for (median, range) nicotine (50.1 ng/g, 3.9-294), cotinine (73.9 ng/g, 6.4-329), and trans-3'-hydroxycotinine (124.5 ng/g, 10.2-478). Quitters (n = 28) self-reported stopping smoking at gestational weeks 2-39. Four meconium specimens from quitters were positive for tobacco biomarkers. Reduced birth weight, length, and head circumference significantly correlated with presence of meconium markers but not with individual or total marker concentrations. Among quitters and smokers, reduced infant birth weight, head circumference, and gestational age correlated with total and average daily cigarette consumption in the second and third trimesters.

CONCLUSION

Smoking cessation or reduction during pregnancy improved neonatal outcomes. The window of detection for tobacco in meconium appears to be the third trimester; however, low exposure in this trimester failed to be detected. These results will aid physicians in educating women who are pregnant or thinking about becoming pregnant on the negative consequences of smoking during pregnancy. In addition, infants at risk can be identified at birth to assist early intervention efforts.

The relationship between maternal opioid agonists and psychiatric medications on length of hospitalization for neonatal abstinence syndrome

OBJECTIVE

To examine the relationship between maternal opioid agonists, methadone, or buprenorphine (BPH), and concurrent psychiatric medication use on length of hospitalization (LOS) among infants with neonatal abstinence syndrome (NAS).

METHODS

We reviewed the charts of infants born at Boston Medical Center between 2003 and 2009 with a diagnosis of NAS whose mothers were prescribed methadone or BPH for opiate addiction. Univariate and multivariate linear regression analyses were used to examine associations between maternal opioid substitution concurrent with psychiatric medication use and infant LOS. We also tested whether exposure to BPH was associated with a shorter hospitalization.

RESULTS

A total of 273 mother-infant pairs were identified. The average LOS for all infants was 22.9 days (SD: 10.9). In bivariate analyses, maternal use of any psychiatric medication was associated with a longer infant LOS (P < 0.005). Compared with those prescribed methadone alone (n = 158), those also taking benzodiazepines (n = 56) had a 5.88-day longer LOS (95% confidence interval [CI]: 2.15-9.60, P = 0.002). Infants of mothers taking methadone plus an selective serotonin re-uptake inhibitor (n = 51) had a longer LOS (β = 4.47, 95% CI: 1.15-7.79) compared to methadone alone; results remained significant in an initial multivariate model, however the effect was attenuated when additional psychiatric medication use was added to the model. Compared with those exposed to methadone, those exposed to BPH (n = 22) had a significantly shorter LOS (ß = -7.35, CI: -0.18 to -14.52, P = 0.04).

CONCLUSIONS

Maternal use of prescribed methadone and benzodiazepines, compared to methadone alone, increased LOS for infants with NAS by 6 days. Maternal use of BPH was associated with a shorter LOS.

Reduction in arterial stiffness and vascular age by naltrexone-induced interruption of opiate agonism: a cohort study

OBJECTIVE

To prospectively assess if opiate antagonist treatment or the opiate-free status could reverse opiate-related vasculopathy.

DESIGN

Longitudinal Open Observational, Serial 'N of One', over 6.5 years under various treatment conditions: opiate dependence, naltrexone and opiate-free.

SETTING

Primary care, Australia.

PARTICIPANTS

20 opiate-dependent patients (16 males: 16 cases of buprenorphine 4.11±1.17 mg, two of methadone 57.5±12.5 mg and two of heroin 0.75±0.25 g).

INTERVENTION

Studies of central arterial stiffness and vascular reference age (RA) were performed longitudinally by SphygmoCor Pulse Wave Analysis (AtCor, Sydney).

PRIMARY OUTCOMES

Primary outcome was vascular age and arterial stiffness accrual under different treatment conditions.

RESULTS

The mean chronological age (CA) was 33.62±2.03 years. The opiate-free condition was associated with a lower apparent vascular age both in itself (males: p=0.0402 and females: p=0.0360) and in interaction with time (males: p=0.0001 and females: p=0.0004), and confirmed with other measures of arterial stiffness. The mean modelled RA was 38.82, 37.73 and 35.05 years in the opiate, naltrexone and opiate-free conditions, respectively. The opiate-free condition was superior to opiate agonism after full multivariate adjustment (p=0.0131), with modelled RA/CA of 1.0173, 0.9563 and 0.8985 (reductions of 6.1% and 11.9%, respectively).

CONCLUSIONS

Data demonstrate that opiate-free status improves vascular age and arterial stiffness in previous chronic opiate users. The role of opiate antagonist treatment in achieving these outcomes requires future clarification and offers hope of novel therapeutic remediation.

Development and validation of the first liquid chromatography-tandem mass spectrometry assay for simultaneous quantification of multiple antiretrovirals in meconium

A novel method for the simultaneous quantification of 16 antiretroviral (ARV) drugs and 4 metabolites in meconium was developed and validated. Quantification of 6 nucleoside/nucleotide reverse transcriptase inhibitors, 2 non-nucleoside reverse transcriptase inhibitors, 7 protease inhibitors, and 1 integrase inhibitor was achieved in 0.25 g of meconium. Specimen preparation included methanol homogenization and solid-phase extraction. Separate positive and negative polarity multiple reaction monitoring mode injections were required to achieve sufficient sensitivity. Linearity ranged from 10 to 75 ng/g up to 2500 ng/g for most analytes and 100-500 ng/g up to 25,000 ng/g for some; all correlation coefficients were ≥0.99. Extraction efficiencies from meconium were 32.8-119.5% with analytical recovery of 80.3-108.3% and total imprecision of 2.2-11.0% for all quantitative analytes. Two analytes with analytical recovery (70.0-138.5%) falling outside the 80-120% criteria range were considered semiquantitative. Matrix effects were -98.3-47.0% and -98.0-67.2% for analytes and internal standards, respectively. Analytes were stable (>75%) at room temperature for 24 h, 4 °C for 3 days, -20 °C for 3 freeze-thaw cycles over 3 days, and on the autosampler. Method applicability was demonstrated by analyzing meconium from HIV-uninfected infants born to HIV-positive mothers on ARV therapy. This method can be used as a tool to investigate the potential effects of in utero ARV exposure on childhood health and neurodevelopmental outcomes.

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.

Methadone and metabolites in hair of methadone-assisted pregnant women and their infants

INTRODUCTION

Methadone is the recommended pharmacotherapy for opioid-dependent pregnant women. The primary aims of this study were to determine whether a dose-concentration relationship exists between cumulative maternal methadone dose, methadone and metabolite concentrations in maternal hair during pregnancy and whether maternal hair methadone and metabolite concentrations predict neonatal outcomes.

MATERIALS AND METHODS

Hair specimens were collected monthly from opioid-dependent mothers enrolled in methadone treatment and 4 of their infants. Hair specimens were segmented (3 cm), washed (maternal hair only), and analyzed for methadone, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP), and 2-ethyl-5-methyl-3,3-diphenylpyrroline by liquid chromatography tandem mass spectrometry.

RESULTS

There was large intersubject variability and no dose-concentration relationship for cumulative methadone dose and methadone, EDDP, 2-ethyl-5-methyl-3,3-diphenylpyrroline, or total concentrations in hair. For individual women, a positive trend was noted for cumulative methadone dose and methadone and EDDP concentrations in hair. There was a positive linear trend for cumulative methadone dose and EDDP/methadone ratio in maternal hair, perhaps reflecting methadone's induction of its own metabolism. Maternal methadone concentrations were higher than those in infant hair, and infant EDDP hair concentrations were higher than those in maternal hair. Maternal methadone dose, and methadone and EDDP hair concentrations were not correlated with peak infant neonatal abstinence syndrome (NAS) scores, days to peak NAS, duration of NAS, time to NAS onset, birth length, head circumference, or amount of neonatal morphine pharmacotherapy. Maternal cumulative third trimester methadone dose was positively correlated with infant birth weight.

CONCLUSIONS

Methadone and EDDP in pregnant women's hair are markers of methadone exposure and do not predict total methadone dose, nor neonatal outcomes from in utero methadone exposure.

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.

Methadone, cocaine, opiates, and metabolite disposition in umbilical cord and correlations to maternal methadone dose and neonatal outcomes

OBJECTIVES

The purpose was to explore methadone and 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine (EDDP) umbilical cord disposition, correlate with maternal methadone dose and neonatal outcomes, and evaluate the window of drug detection in umbilical cord of in utero illicit drug exposure.

METHODS

Subjects comprised 19 opioid-dependent pregnant women from 2 clinical studies, one comparing methadone and buprenorphine pharmacotherapy for opioid-dependence treatment and the second examining monetary reinforcement schedules to maintain drug abstinence. Correlations were calculated for methadone and EDDP umbilical cord concentrations and maternal methadone dose, and neonatal outcomes. Cocaine- and opiate-positive umbilical cord concentrations were compared with those in placenta and meconium, and urine specimens collected throughout gestation.

RESULTS

Significant positive correlations were found for umbilical cord methadone concentrations and methadone mean daily dose, mean dose during the third trimester, and methadone cumulative daily dose. Umbilical cord EDDP concentrations and EDDP/methadone concentration ratios were positively correlated to newborn length, peak neonatal abstinence syndrome (NAS) score, and time-to-peak NAS score. Methadone concentrations and EDDP/methadone ratios in umbilical cord and placenta were positively correlated. Meconium identified many more cocaine- and opiate-positive specimens than did umbilical cord.

CONCLUSIONS

Umbilical cord methadone concentrations were correlated to methadone doses. Also, our results indicate that methadone and EDDP concentrations might help to predict the NAS severity. Meconium proved to be more suitable than umbilical cord to detect in utero exposure to cocaine and opiates; however, umbilical cord could be useful when meconium is unavailable due to in utero or delayed expulsion.