Maternal opioid exposure, neonatal abstinence syndrome, and infant healthcare utilization: A retrospective cohort analysis

Advances in animal models of prenatal opioid exposure

Neonatal opioid withdrawal syndrome (NOWS) is a growing public health concern. The complexity of in utero opioid exposure in clinical studies makes it difficult to investigate underlying mechanisms that could ultimately inform early diagnosis and treatments. Clinical studies are unable to dissociate the influence of maternal polypharmacy or the environment from direct effects of in utero opioid exposure, highlighting the need for effective animal models. Early animal models of prenatal opioid exposure primarily used the prototypical opioid, morphine, and opioid exposure that was often limited to a narrow period during gestation. In recent years, the number of preclinical studies has grown rapidly. Newer models utilize both prescription and nonprescription opioids and vary the onset and duration of opioid exposure. In this review, we summarize novel prenatal opioid exposure models developed in recent years and attempt to reconcile results between studies while critically identifying gaps within the current literature.

Neonatal Abstinence Signs during Treatment: Trajectory, Resurgence and Heterogeneity

Neonatal abstinence syndrome (NAS) presents with a varying severity of withdrawal signs and length of treatment (LOT). We examined the course and relevance of each of the NAS withdrawal signs during treatment in a sample of 182 infants with any prenatal opioid exposure, gestational age ≥ 35 weeks, without other medical conditions, and meeting the criteria for pharmacological treatment. Infants were monitored using the Finnegan Neonatal Abstinence Scoring Tool. Daily mean Finnegan scores were estimated using linear mixed models with random subject effects to account for repeated withdrawal scores from the same subject. Daily item prevalence was estimated using generalized estimating equations with a within-subject exchangeable correlation structure. The median LOT was 12.86 days. The prevalence of withdrawal signs decreased from day one to day three of treatment. However, certain central nervous system (CNS) and gastrointestinal (GI) signs showed sporadic increases in prevalence notable around two weeks of treatment, accounting for increases in Finnegan scores that guided pharmacotherapy. We question whether the resurgence of signs with a prolonged LOT is mainly a consequence of opioid tolerance or withdrawal. Monitoring CNS and GI signs throughout treatment is crucial. Future studies directed to better understand this clinical phenomenon may lead to the refining of NAS pharmacotherapy and perhaps the discovery of treatment alternatives.

Priorities for Well Child Care of Families Affected by Parental Opioid Use Disorder

BACKGROUND AND OBJECTIVES

Parenting women in treatment for opioid use disorder (OUD) report a lack of family centeredness and anticipatory guidance within well child care (WCC), and WCC utilization is low among affected children. We explore priorities for WCC visit content to inform primary care recommendations for this population.

METHODS

This study is a qualitative study of parenting women from one urban, academic OUD treatment program and pediatric primary care clinicians from a nearby affiliated pediatric practice. Eligible parent participants had a child ≤2 years old and were English speaking. Semistructured interviews elicited perspectives on WCC, with questions and prompts related to visit content. Inductive thematic analysis was led by 2 investigators using open coding procedures.

RESULTS

Among 30 parent participants, the majority were White (83%) and unmarried (90%). Approximately 60% reported their child received pharmacotherapy for neonatal opioid withdrawal syndrome. Of 13 participating clinicians, 9 were attending pediatricians. Five themes emerged from parental and clinician interviews: (1) improving knowledge and confidence related to child development, behavior, and nutrition; (2) mitigating safety concerns; (3) addressing complex health and subspecialty needs through care coordination; (4) acknowledging parental health and wellbeing in the pediatric encounter; and (5) supporting health education and care related to neonatal opioid withdrawal syndrome. Parents and clinicians expressed difficulty comprehensively addressing such issues due to time constraints, social determinants of health, and significant informational needs.

CONCLUSIONS

Parenting women in treatment for OUD and pediatric clinicians share multiple priorities for anticipatory guidance within WCC visits and barriers to addressing them comprehensively.

Medications for Opioid Use Disorder During the Prenatal Period and Infant Outcomes

This cross-sectional study explores the association between mothers’ receipt of opioid use disorder treatment during pregnancy and their infants’ health services use in the first year of life.

Maternal Opioid Use Disorder and the Risk of Postneonatal Infant Mortality

Importance

The risk of serious long-term outcomes for infants born to individuals with opioid use disorder (OUD) is not fully characterized, nor is it well understood whether risks are modified by infant diagnosis of neonatal opioid withdrawal syndrome (NOWS).

Objective

To characterize the risk of postneonatal infant mortality among infants with a NOWS diagnosis or born to individuals with OUD.

Design, Setting, and Participants

The study team conducted a retrospective cohort study of 390 075 infants born from 2007 through 2018 to mothers who were enrolled in Tennessee Medicaid from 183 days prior to delivery through 28 days post partum (baseline). Maternal and infant baseline characteristics were measured using administrative claims and birth certificates, and infants were followed up from day 29 post partum through day 365 or death. Deaths were identified using linked death certificates through 2019. These data were analyzed from February 10, 2022, through March 3, 2023.

Exposure

Infant exposures included birth to an individual with OUD or postnatal diagnosis of NOWS. The study team defined a pregnant individual's OUD status (maternal OUD) as having OUD diagnosis or a maintenance medication prescription fill during baseline; this study defined NOWS as having NOWS diagnosis up to day 28. Groups were categorized by exposures as maternal OUD with NOWS (OUD positive/NOWS positive), maternal OUD without NOWS (OUD positive/NOWS negative), no documented maternal OUD with NOWS (OUD negative/NOWS positive), and no documented maternal OUD or NOWS (OUD negative/NOWS negative, unexposed).

Main Outcome and Measures

The outcome was postneonatal infant death, confirmed by death certificates. Cox proportional hazards models were used, adjusting for baseline maternal and infant characteristics, to estimate adjusted hazard ratios (aHRs) and 95% CIs for the association between maternal OUD or NOWS diagnosis with postneonatal death.

Results

Pregnant individuals in the cohort had a mean (SD) age of 24.5 (5.2) years; 51% of infants were male. The study team observed 1317 postneonatal infant deaths and incidence rates of 3.47 (OUD negative/NOWS negative, 375 718), 8.41 (OUD positive/NOWS positive, 4922); 8.95 (OUD positive/NOWS negative, 7196), and 9.25 (OUD negative/NOWS positive, 2239) per 1000 person-years. After adjustment, the risk of postneonatal death was elevated for all groups, relative to the unexposed: OUD positive/NOWS positive (aHR, 1.54; 95% CI, 1.07-2.21), OUD positive/NOWS negative (aHR, 1.62; 95% CI, 1.21-2.17), and OUD negative/NOWS positive (aHR, 1.64; 95% CI, 1.02-2.65).

Conclusions and Relevance

Infants born to individuals with OUD or with a NOWS diagnosis had an increased risk of postneonatal infant mortality. Future work is necessary to create and evaluate supportive interventions for individuals with OUD during and after pregnancy to reduce adverse outcomes.

Neonatal Abstinence Syndrome in Infants with Prenatal Exposure to Methadone versus Buprenorphine

Neonatal abstinence syndrome (NAS) has been of increasing concern. Studies suggest that prenatal exposure to buprenorphine may be preferred to methadone in regard to neonatal withdrawal. Our aim was to determine whether the incidence and severity of NAS are different between babies prenatally exposed to methadone or buprenorphine in pregnancy. This retrospective analysis of infants ≥ 35-weeks-old exposed to methadone/buprenorphine alone or in conjunction with other substances in utero. They were divided into four groups: 1-methadone alone (Met), 2-buprenorphine alone (Bup), 3 and 4-those exposed to methadone and buprenorphine, respectively, in conjunction with other drugs (Met+ and Bup+). The frequency of NAS treatment, duration of treatment (LOT) and length of stay (LOS) were compared between groups. Of the 290 mothers, 59% were in the Met group, 18% in the Bup group, 14% in the Met or Bup and another opiate group, and 9% took methadone or buprenorphine plus various other substances. Infants born to Met/Met+ mothers had a four-times higher likelihood of developing NAS (p < 0.001). There was no difference in the LOS (p = 0.08) or LOT (p = 0.11) between groups. The buprenorphine treatment in pregnancy decreased the risk of babies developing NAS. However, once the NAS required pharmacological treatment, the type of maternal prenatal exposure did not affect the LOS or LOT.

Pediatric Primary Care Diagnoses Among Children with Intrauterine Opioid Exposure

BACKGROUND AND OBJECTIVES

Characterizing common concerns for children with intrauterine opioid exposure (IOE) can inform tailored primary care.

METHODS

Retrospective analysis of primary care data of children with IOE from birth to age two years within one multi-state pediatric health system. Well child care (WCC) and problem-based visit diagnoses were categorized, and descriptive statistics were tabulated.

RESULTS

Three hundred and eighty-five (385) children with IOE had 3,622 primary care visits, of which 51.4% were WCC and 48.6% were problem-based. Most frequent visit diagnoses were upper respiratory complaints (14.8% of visits), feeding difficulties (12.2%), and perinatal viral exposure (9.8%). Although visit type (WCC vs. problem-based) varied across diagnostic category, frequent utilization of both visit types were documented for several diagnoses in infancy (e.g., fussiness/colic, feeding difficulties).

CONCLUSIONS

Well child care visits for children with IOE are key opportunities for anticipatory guidance with an emphasis on problems that may contribute to acute health care utilization, particularly in early infancy.

Resource utilization and convalescent care cost in neonatal opioid withdrawal syndrome

BACKGROUND: Neonatal opioid withdrawal syndrome (NOWS) is a growing public health problem associated with complex and prolonged medical care and a significant resource utilization burden. The objective of this study was to compare the cost of different convalescent care settings for infants with NOWS. METHODS: Retrospective comparison study of infants with NOWS discharged directly from NICU, transferred to an acute care pediatric floor (PPCU) or rehabilitation hospital (PRH). Primary outcomes were length of stay (LOS) and cost of stay (COS). RESULTS: Infants had 1.3 (95% CI: 1.1,1.6) times and 2.5 (95% CI: 2.1,3.1) times significantly longer mean LOS for PPCU and RH discharges compared to NICU discharges. NICU discharged infants had the lowest mean COS ($25,745.00) and PRH the highest ($60,528.00), despite PRH having a lower cost per day. PRH discharged infants had higher rates of methadone and benzodiazepine and less buprenorphine exposure than NICU/PPCU discharged. Infants born to mothers on marijuana and buprenorphine had a 28% lower mean COS compared to unexposed infants. Median treatment cumulative morphine doses were six-fold higher for PRH than NICU discharge. CONCLUSIONS: Infants transferred to convalescence care facilities had longer and more costly admissions and received more medication. However, there may be a role for earlier transfer of a subset of infants at-risk for longer LOS as those exposed to methadone and/or benzodiazepines. Further studies exploring differences in resource utilization, convalescent care delivery and cost expenditure are recommended.

Healthcare utilization among children with a history of neonatal opioid withdrawal syndrome: A matched cohort study

OBJECTIVES

Compare longitudinal healthcare utilization patterns in children with and without a history of neonatal opioid withdrawal syndrome (NOWS).

STUDY DESIGN

A retrospective matched cohort study was conducted using billing data extracted from between 2003 and 2016 in North Texas hospitals. The sample included 595 pediatric patients diagnosed with NOWS (i.e. exposed). The unexposed were patients not diagnosed with NOWS and matched 4:1 on sex, age at first encounter, and ethnicity to the exposed who received care during the same period. Multi-level regression models (accounting for clustered data structure of multiple visits per patient) compared number of hospitalizations, number of outpatient visits, number of emergency department (ED) visits, average length of stay, and healthcare expenditures across patients with and without NOWS.

RESULTS

Hospitalizations were significantly lower among exposed (Incidence Rate Ratio [IRR] = 0.58, 95 % Confidence Interval [CI] = 0.44-0.77) compared to unexposed. Outpatient visits, ED visits, and average length of stay was significantly higher among exposed compared to unexposed (IRR = 1.19, 95 % CI = 1.04-1.36; IRR = 1.22, 95 % CI = 1.04-1.42; IRR = 2.21, 95 % CI = 2.03-2.42, respectively). Overall healthcare expenditure was greater among exposed, as well as for patients with neurologic, endocrine, cardiac, mental disorders, respiratory, perinatal, infectious disease, eye, ear, digestive, congenital anomaly, and skin diagnoses.

CONCLUSIONS

Children with a diagnosis of NOWS have significantly higher healthcare expenditures, and with the exception of hospitalizations, higher healthcare utilization beyond the newborn visit. These findings suggest the needs for interventions for children with NOWS beyond the immediate neonatal period.

The Effects of Opioid Use during Pregnancy on Infant Health and Well-Being

In this study, we estimate the first causal effects of in utero opioid exposure on infant health at birth and child protective services reports. We employ maternal fixed-effects models using linked administrative data capturing 259,723 infants born to 176,224 mothers enrolled in Medicaid between 2010 and 2019. Our preferred specifications suggest that neonatal abstinence syndrome and NICU admission bear strong associations with prenatal opioid exposure, concentrated on illicit and medication assisted treatment (MAT) exposure in the first and third trimesters. We find that prenatal opioid exposure is associated with increased CPS reports, low birth weight, preterm birth, and small for gestational age, though these measures are less sensitive with respect to the timing of exposure. While we detect relatively smaller effects of non-MAT prescription opioid exposure on NAS, NICU admission, low birthweight, these effects are not trivial, suggesting that medical professionals should consider balancing the potential for adverse side effects of infants with the benefits of pain management for pregnant women.

Suboxone: History, controversy, and open questions

There are more than 200 opioid overdose deaths each day in the US. In combating this epidemic we look to available treatment tools. Here, we find only three medications approved by the Food and Drug Administration (FDA) for the treatment of opioid use disorder. Of the three, buprenorphine is of particular importance due to its reduced overdose potential as a partial opioid agonist. Evidence supports its clinical equivalence to its full agonist cousin methadone, and suggests that it is better slated for long-term treatment of opioid use disorder compared to the non-selective opioid antagonist naltrexone. Buprenorphine is most popularized within Suboxone, a medication which also contains the non-selective opioid antagonist naloxone. The naloxone has no additional effect when the drug is taken as instructed, as it is intended to prevent diversion in those that would attempt to inject the medication. While Suboxone is regarded by some as the future of medical treatment, others have expressed concerns. This review aims to explore the history, controversy, and open questions that surround buprenorphine and its most prescribed variation, Suboxone. These include its pharmacological, legislative, and social history, alternative indications, efficacy as a treatment of opioid use disorder, and more. Armed with this information, the reader will have a more in-depth and holistic understanding of the medication's place in their community.

The impact of opioid exposure during pregnancy on the human neonatal immune profile

BACKGROUND

The increasing magnitude of the opioid crisis and rising rates of neonatal abstinence syndrome (NAS) diagnoses highlight the need for increased research into how maternal substance use during pregnancy can impact the neonatal immune profile and its functionality. We hypothesized that neonates with opioid exposure would have reduced proportions of some immune cells, an anti-inflammatory cytokine profile, reduced T cell proliferation, and monocyte bacterial killing activity compared to the control population.

METHODS

The present study compares immune cell populations, inflammatory and anti-inflammatory cytokine and chemokine levels in the serum, and monocyte and T cell functional activity using umbilical cord samples from neonates with known opioid exposure during gestation and from control neonates without known exposure.

RESULTS

Our findings demonstrated a significant reduction in neutrophils, decreased levels of inflammatory cytokines in the serum, and reduced IL-2 production during in vitro CD4⁺ T cell proliferation in neonates exposed to opioids compared to controls. The neutrophil findings were supported by retrospective analysis of an extended network of deidentified patient records.

CONCLUSIONS

This study is the first of its kind to evaluate differences in neonatal immunity as a result of opioid exposure in the human population that will inform continued mechanistic studies.

IMPACT

The opioid epidemic has become a public health crisis in the United States, and the corresponding incidence of neonatal abstinence syndrome (NAS) have risen accordingly. New research is required to understand the short and long-term health impacts of opioid exposure to the neonate. This is the first human study to investigate the immunologic profile and functionality in neonates with known opioid exposure in utero. The abundance of neutrophils and the ratio of neutrophils to lymphocytes is significantly reduced along with inflammatory cytokines and chemokines following opioid exposure during pregnancy. The immune profile in opioid-exposed neonates may promote susceptibility to infection.