Ethanol, Neurodevelopment, Infant and Child Health (ENRICH) prospective cohort: Study design considerations

Impact of low-level prenatal alcohol exposure and maternal stress on autonomic regulation

BACKGROUND

Prenatal alcohol exposure (PAE) impacts the neurodevelopment of the fetus, including the infant's ability to self-regulate. Heart rate variability (HRV), that is, the beat-to-beat variability in heart rate, is a non-invasive measurement that can indicate autonomic nervous system (ANS) function/dysfunction.

METHODS

The study consisted of a subset of our ENRICH-2 cohort: 80 participants (32 PAE and 48 Controls) who had completed three visits during pregnancy. The participants completed a comprehensive assessment of PAE and other substances throughout pregnancy and assessments for stress, anxiety, and depression in the third trimester. At 24 h of age, infant HRV was assessed in the hospital during the clinically indicated heel lance; 3- to 5-min HRV epochs were obtained during baseline, heel lancing, and recovery episodes.

RESULTS

Parameters of HRV differed in infants with PAE compared to Controls during the recovery phase of the heel lance (respiratory sinus arrhythmia (RSA) and high-frequency (HF), p < 0.05). Increased maternal stress was also strongly associated with abnormalities in RSA, HF, and low-frequency / high-frequency (LF/HF, p's < 0.05).

CONCLUSIONS

Alterations in ANS regulation associated with PAE and maternal stress may reflect abnormal development of the hypothalamic-pituitary-adrenal axis and have long term implications for infant responsiveness and self-regulation.

IMPACT

Previous studies have focused on effects of moderate to heavy prenatal alcohol exposure (PAE) on autonomic dysregulation, but little is known about the effects of lower levels of PAE on infant self-regulation and heart rate variability (HRV). Prenatal stress is another risk factor for autonomic dysregulation. Mild PAE impacts infant self-regulation, which can be assessed using HRV. However, the effect of prenatal stress is stronger than that of mild PAE or other mental health variables on autonomic dysregulation.

Effects of medications for opioid use disorder (MOUD) on fetal brain and cranial measurements

BACKGROUND

The use and misuse of opioids, as well as opioid use disorder (OUD) have increased remarkably among reproductive-aged and pregnant women. As many as 25% of pregnant women who report non-medical opioid use in the past month also report concurrent alcohol use. While teratogenic effects of alcohol are well established, there are limited studies evaluating fetal intracranial effects associated with medications for OUD (MOUD) and concurrent use of MOUD and alcohol during pregnancy. The objective of this study was to determine the effect of MOUD, with and without concomitant alcohol use, on fetal intracranial measurements. The type of maternal MOUD therapy (methadone vs. buprenorphine) was also examined.

METHODS

This study was a secondary analysis of a prospective cohort study among participants (n = 196) assigned into three groups (MOUD [n = 94], MOUD+Alcohol [n = 47], and unexposed controls [n = 55]). Co-exposure with either methamphetamines or cocaine were exclusionary criteria; other co-exposures were carefully characterized with prospective repeated self-report measures and biomarkers. Fetal ultrasound measurements at 18-22 weeks (2nd trimester) and 28-32 weeks (early 3rd trimester) were compared among study groups. In addition to standard morphometrics, we performed specialized intracranial measurements of caval-calvarial distance (CCD), frontal lobe width (FLW), frontal lobe length (FLL), and fronto-thalamic distance (FTD).

RESULTS

Brain and cranial measurements between MOUD, with or without alcohol co-exposure, and unexposed controls were generally not significantly different in multivariable analyses. Subjects in the MOUD groups had earlier gestational age at delivery and lower birth weight and birth weight percentile compared to unexposed controls with differences driven primarily by the methadone subgroup. Significant differences in standard and specialized intracranial indices at both second and third trimester as well as differences in the change of HC percentile over time were observed in the methadone subgroup compared to controls, while no differences between buprenorphine subgroup and controls were observed for any measures.

CONCLUSION

Patients receiving methadone therapy might require closer monitoring during pregnancy; however, detailed imaging of the fetal brain other than the standard measurements might not be warranted.

Prenatal opioid-exposed infant extracellular miRNA signature obtained at birth predicts severity of neonatal opioid withdrawal syndrome

Prenatal opioid exposure (POE) is commonly associated with neonatal opioid withdrawal syndrome (NOWS), which is characterized by a broad variability in symptoms and severity. Currently there are no diagnostic tools to reliably predict which infants will develop severe NOWS, while risk stratification would allow for proactive decisions about appropriate clinical monitoring and interventions. The aim of this prospective cohort study was to assess if extracellular microRNAs (miRNAs) in umbilical cord plasma of infants with POE could predict NOWS severity. Participants (n = 58) consisted of pregnant women receiving medications for opioid use disorder and their infants. NOWS severity was operationalized as the need for pharmacologic treatment and prolonged hospitalization (≥ 14 days). Cord blood miRNAs were assessed using semi-quantitative qRT-PCR arrays. Receiver operating characteristic curves and area under the curve (AUC) were estimated. The expression of three miRNAs (miR-128-3p, miR-30c-5p, miR-421) predicted need for pharmacologic treatment (AUC: 0.85) and prolonged hospitalization (AUC: 0.90). Predictive validity improved after two miRNAs (let-7d-5p, miR-584-5p) were added to the need for pharmacologic treatment model (AUC: 0.94) and another two miRNAs (let-7b-5p, miR-10-5p) to the prolonged hospitalization model (AUC: 0.99). Infant cord blood extracellular miRNAs can proactively identify opioid-exposed neonates at high-risk for developing severe NOWS.

Prevalence of marijuana use in pregnant women with concurrent opioid use disorder or alcohol use in pregnancy

BACKGROUND

A quarter of pregnant women use alcohol, 6.5/1000 deliveries are affected by opioid use disorder (OUD), and the prevalence of cannabis use in pregnant women is increasing. However, marijuana co-exposure in polysubstance-using women is not well described.

METHODS

The well-characterized ENRICH-1 cohort (n = 251), which focused on the effects of two primary exposures of interest-opioids and alcohol, was used to (1) estimate the prevalence/frequency of marijuana use in those with OUD and/or alcohol use, and (2) examined correlates of marijuana use. Participants were classified into an OUD group (n = 125), Alcohol group (n = 69), and concurrent OUD and Alcohol (OUD + Alcohol) group (n = 57). Self-report and biomarkers ascertained substance use. Multivariable logistic regression identified correlates of marijuana use.

RESULTS

The prevalence of any marijuana use in pregnancy was 43.2%, 52.6%, and 46.4% in the OUD, OUD + Alcohol, and Alcohol groups, respectively. Correspondingly, weekly or daily use was reported by 19.4%, 21.0%, and 24.6% of participants. In the OUD and OUD + Alcohol groups, the proportion of women using marijuana was significantly higher in those taking buprenorphine (45.8% and 58.3%, respectively) compared to women using methadone (37.5% and 42.9%, respectively). Mean maternal age was lower in women who used marijuana in all three groups compared to non-marijuana users. Independent correlates of marijuana use (controlling for group, race/ethnicity, education, and smoking) were maternal age (adjusted Odds Ratio (aOR) per 5-year increment 0.61; (95% CI 0.47, 0.79)), and polysubstance use (aOR 2.02; 95% CI 1.11, 3.67). There was a significant interaction between partnership status and group: among women who were not in a partnership, those in the OUD and OUD + Alcohol groups had lower odds of marijuana use relative to the Alcohol group. For women in the Alcohol group, partnered women had lower odds of marijuana use than un-partnered women (aOR 0.12; 95% CI: 0.02, 0.68).

CONCLUSIONS

Results indicate a relatively high prevalence and frequency of marijuana use in pregnant women being treated for OUD and/or women consuming alcohol while pregnant. These results highlight the need for ongoing risk reduction strategies addressing marijuana use for pregnant women receiving OUD treatment and those with alcohol exposure.

Fifty Years of Research on Prenatal Substances: Lessons Learned for the Opioid Epidemic

Current efforts to design research on developmental effects of prenatal opioid exposure can benefit from knowledge gained from 50 years of studies of fetal alcohol and prenatal drug exposures such as cocaine. Scientific advances in neurobiology, developmental psychopathology, infant assessments, genetics, and imaging support the principles of developmental neurotoxicology that guide research in prenatal exposures. Important to research design is accurate assessment of amount, frequency, and timing of exposure which benefits from accurate self-report and biomarkers of exposure. Identifying and control of pre- and postnatal factors that impact development are difficult and dependent on appropriate research design and selection of comparison groups and measurement of confounding, mediating, and moderating variables. Polysubstance exposure has increased due to the number of prescribed and nonprescribed substances used by pregnant women and varying combinations of drugs may have differential effects on the outcome. Multiple experimental and clinical assessments of infant behavior have been developed but predicting outcome before 18-24 months of age remains difficult. With some exceptions, prenatal substance exposure effect sizes have been small, and cognitive and behavioral effects tend to be specific rather than global. Studies require large sample sizes, adequate retention, and support for social services in at-risk samples. The ethical and legal contexts and stigma associated with drug/alcohol use disorder should be considered in order to prevent harm to families in research programs. Recognition of the pervasive use of addictive substances in this nation should lead to broad scientific efforts to understand how substances affect child outcomes and to initiate prevention and intervention where needed.

The association between prenatal alcohol exposure and protein expression in human placenta

BACKGROUND

The need for earlier recognition of children at risk for neurobehavioral problems associated with prenatal ethanol exposure (PAE) has prompted investigations of biomarkers prognostic for altered fetal development. Here, we examined whether PAE alters the expression of angiogenesis-related proteins and cytokines in human placenta in subjects from an Ethanol, Neurodevelopment, Infant and Child Health prospective cohort.

METHODS

PAE was ascertained by screening questionnaires, Time-line Follow-back interviews and a panel of ethanol biomarkers at two study visits. After delivery, placental tissue samples were collected for protein analysis.

RESULTS

No significant differences in the prevalence of substance use, demographic or medical characteristics were observed between the No PAE and PAE groups. PAE was associated with significant reductions in placental expression of VEGFR2 and annexin-A4, while the levels of VEGFR1 and CCM-3 trended downward. A trend toward higher expression of the cytokines TNF-α and IL-13 was also observed in the PAE group. Receiver operating characteristic analyses of the data demonstrated a moderate-to-high degree of diagnostic accuracy for individual placental proteins. Combinations of proteins substantially increased their ability to differentiate between PAE and No PAE subjects.

CONCLUSIONS

These results establish the feasibility of harvesting placental tissue for protein analyses of PAE in a prospective manner. In addition, given the importance of vascular remodeling in both placenta and developing brain, the role of angiogenic and cytokine proteins in this process warrants further investigation for their utility for predicting alterations in brain development, as well as their mechanistic role in PAE-induced pathology.

Magnetoencephalography and the infant brain

Magnetoencephalography (MEG) is a non-invasive neuroimaging technique that provides whole-head measures of neural activity with millisecond temporal resolution. Over the last three decades, MEG has been used for assessing brain activity, most commonly in adults. MEG has been used less often to examine neural function during early development, in large part due to the fact that infant whole-head MEG systems have only recently been developed. In this review, an overview of infant MEG studies is provided, focusing on the period from birth to three years. The advantages of MEG for measuring neural activity in infants are highlighted (See Box 1), including the ability to assess activity in brain (source) space rather than sensor space, thus allowing direct assessment of neural generator activity. Recent advances in MEG hardware and source analysis are also discussed. As the review indicates, efforts in this area demonstrate that MEG is a promising technology for studying the infant brain. As a noninvasive technology, with emerging hardware providing the necessary sensitivity, an expected deliverable is the capability for longitudinal infant MEG studies evaluating the developmental trajectory (maturation) of neural activity. It is expected that departures from neuro-typical trajectories will offer early detection and prognosis insights in infants and toddlers at-risk for neurodevelopmental disorders, thus paving the way for early targeted interventions.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Role of caregiver-reported outcomes in identification of children with prenatal alcohol exposure during the first year of life

BACKGROUND

Earlier identification of children with prenatal alcohol exposure (PAE) remains a challenge. The objective of this study was to identify neurobehavioral (NB) outcomes associated with PAE in infants.

METHODS

This manuscript evaluates NB outcomes at 6.33±1.12 months of age in 93 infants (39 PAE and 54 No-PAE) recruited prospectively into the ENRICH cohort. PAE was assessed by prospective repeated TLFB interviews and a panel of ethanol biomarkers. NB outcomes were evaluated by the Bayley Scales of Infant Development (BSID-III), Parenting Stress Index (PSI), Infant Behavior Questionnaire (IBQ-R), and Infant Sensory Profile (ISP).

RESULTS

Mean maternal age at enrollment was 28.18±5.75, and 64.52% were Hispanic/Latina. Across three TLFB calendars, absolute alcohol per day in the PAE group was 0.44±0.72, corresponding to low-moderate alcohol consumption. While no association was observed between PAE and BSID-III (P's>0.05), PAE was associated with higher scores on the PSI difficult child scale ([Formula: see text]=13.9; P=0.015), total stress ([Formula: see text]=13.9; P=0.010), and IBQ negative affect ([Formula: see text]=8.60; P=0.008) measures after adjustment for covariates.

CONCLUSIONS

Caregiver-reported assessments may provide a currently unrecognized opportunity to identify behavioral deficits, point to early interventions, and should be included in clinical assessments of infants at-risk for fetal alcohol spectrum disorder.

Prevalence of alcohol use in pregnant women with substance use disorder

BACKGROUND

Prenatal care programs for women with opioid use disorder (OUD) often focus treatment/counseling plans around illicit substances, while concurrent use of alcohol might present an equal or greater risk to the fetus.

METHODS

This study evaluated self-reported prevalence of alcohol use in patients participating in a comprehensive prenatal care program for women with substance use disorder (SUD; n = 295), of which 95% are treated for OUD, and pregnant women being served through general obstetrical clinics at the University of New Mexico (n = 365). During the screening phase of a prospective study, patients were asked to report alcohol use in the periconceptional period, and between the last menstrual period and pregnancy recognition.

RESULTS

The screening interview was conducted at 22.3 (median = 22; Q1 = 16; Q3 = 29) gestational weeks. Among patients screened at the SUD clinic, 28.8% and 24.1% reported at least one binge drinking episode in the periconceptional period and in early pregnancy, respectively. The prevalence of binge drinking was similar in the general obstetrics population (24.7% and 24.4%, respectively). Among those who reported drinking in early pregnancy, median number of binge drinking episodes was higher among patients screened at the SUD clinic (median = 3; Q1 = 1; Q3 = 10) compared to the general obstetrics group (median = 1; Q1 = 1; Q3 = 3; p < 0.001).

CONCLUSIONS

This study demonstrates a high prevalence of prenatal alcohol use in early pregnancy in both groups, while patients with SUD/OUD consume more alcohol. These findings underscore the need for targeted screening and intervention for alcohol use in all pregnant women, especially those with SUD/OUD.

Hepatitis C Cascade of Care Among Pregnant Women on Opioid Agonist Pharmacotherapy Attending a Comprehensive Prenatal Program

Background Given the large increases in opioid use among pregnant women and associations with hepatitis C virus (HCV) infection, screening pregnant women who are on (opioid agonist) pharmacotherapy for HCV infection has potential to inform medical care for these mothers as well as their newborns. We investigated the HCV testing cascade among pregnant women on pharmacotherapy in order to describe exposure and infection rates and to identify opportunities that would improve care. Methods Secondary analyses of laboratory results were performed for HCV testing, including anti-HCV, viremia (RNA) and genotype. Information was abstracted from the medical records of women who were followed at a comprehensive prenatal care clinic for women with substance use disorders at the University of New Mexico. Results The sample included 190 pregnant women, of whom 188 were on pharmacotherapy (43.7% on buprenorphine and 55.3% on methadone); the remaining two had tested positive for heroin or prescription opioids. A total of 178 (93.7%) were tested for anti-HCV, 94 (98.9%) of whom were tested for RNA, and 41 (57.7%) were genotyped. Prevalence of exposure to HCV by anti-HCV results was 53.3%, and 37.3% were positive for HCV RNA indicating chronic infection. Conclusions The high prevalence of exposure and infection with HCV in pregnant women involved in pharmacotherapy for a substance use disorder indicate a need for ongoing surveillance and testing for HCV. Identifying HCV during pregnancy is crucial because this identification would serve to enhance medical care and potentially prevent vertical transmission. Identifying HCV would also facilitate referrals to newly available curative HCV treatments following delivery.

Dietary Intake Among Opioid- and Alcohol-Using Pregnant Women

BACKGROUND

Substance abuse in nonpregnant adults has been associated with increased intake in calories and decreased intake of nutrient-dense foods; however, studies examining dietary intake in opioid-using and alcohol-using pregnant women are lacking.

OBJECTIVE

The objective of this study was to evaluate dietary intake in opioid-using pregnant women with or without concurrent light-to-moderate alcohol use as compared to abstaining controls.

METHODS

This prospective birth cohort included 102 pregnant women classified into four study groups: controls (n = 27), medication-assisted treatment (MAT; n = 26), alcohol (ALC; n = 22), and concurrent use of both substances (MAT + ALC; n = 27). Percentage differences in macro- and micronutrient intake were estimated from the food frequency questionnaire and compared among the study groups. Proportions of participants with intakes below the estimated average requirements (EAR) based on diet and diet with supplements were estimated.

RESULTS

Three exposed groups had lower prevalence of multivitamin use in periconceptional period (11.5-31.8%) than controls (44.4%). Unadjusted mean energy intake was significantly higher in the MAT + ALC group compared to controls, while micronutrient intake per 1000 kcal was the highest in the control group for almost all of the micronutrients analyzed. After adjustment for energy intake and sociodemographic characteristics, MAT group had lower estimated dietary intake of iron (-15.0%, p = 0.04) and folate (-16.8%, p = 0.04) compared to controls. A high proportion of participants in all study groups had dietary intake below the EAR for vitamin E, iron, and folate.

CONCLUSION

Results highlight the need for targeted dietary interventions for opioid-using pregnant women.

Hypersynchrony in MEG spectral amplitude in prospectively-identified 6-month-old infants prenatally exposed to alcohol

Early identification of children who experience developmental delays due to prenatal alcohol exposure (PAE) remains a challenge for individuals who do not exhibit facial dysmorphia. It is well-established that children with PAE may still exhibit the cognitive and behavioral difficulties, and individuals without facial dysmorphia make up the majority of individuals affected by PAE. This study employed a prospective cohort design to capture alcohol consumption patterns during pregnancy and then followed the infants to 6 months of age. Infants were assessed using magnetoencephalography to capture neurophysiological indicators of brain development and the Bayley Scales of Infant Development-III to measure behavioral development. To account for socioeconomic and family environmental factors, we employed a two-by-two design with pregnant women who were or were not using opioid maintenance therapy (OMT) and did or did not consume alcohol during pregnancy. Based on prior studies, we hypothesized that infants with PAE would exhibit broad increased spectral amplitude relative to non-PAE infants. We also hypothesized that the developmental shift from low to high frequency spectral amplitude would be delayed in infants with PAE relative to controls. Our results demonstrated broadband increased spectral amplitude, interpreted as hypersynchrony, in PAE infants with no significant interaction with OMT. Unlike prior EEG studies in neonates, our results indicate that this hypersynchrony was highly lateralized to left hemisphere and primarily focused in temporal/lateral frontal regions. Furthermore, there was a significant positive correlation between estimated number of drinks consumed during pregnancy and spectral amplitude revealing a dose-response effect of increased hypersynchrony corresponding to greater alcohol consumption. Contrary to our second hypothesis, we did not see a significant group difference in the contribution of low frequency to high frequency amplitude at 6 months of age. These results provide new evidence that hypersynchrony, previously observed in neonates prenatally exposed to high levels of alcohol, persists until 6 months of age and this measure is detectable with low to moderate exposure of alcohol with a dose-response effect. These results indicate that hypersynchrony may provide a sensitive early marker of prenatal alcohol exposure in infants up to 6 months of age.

The effect of prenatal substance use and maternal contingent responsiveness on infant affect

BACKGROUND

The effects of prenatal substance exposure on neurobehavioral outcomes are inherently confounded by the effects of the postnatal environment, making it difficult to disentangle their influence. The goal of this study was to examine the contributing effects of prenatal substance use and parenting style (operationalized as contingent responding during the play episodes of the Still-face paradigm [SFP]) on infant affect.

METHODS

A prospective cohort design was utilized with repeated assessment of substance use during pregnancy and the administration of the SFP, which measures infant response to a social stressor, at approximately 6months of age. Subjects included 91 dyads classified into four groups: 1) Control (n=34); 2) Medication assisted therapy for opioid dependence (MAT; n=19); 3) Alcohol (n=15); 4) Alcohol+MAT (n=23). Mean % of positive infant affect and mean % of maternal responsiveness (watching, attention seeking, and contingent responding) was compared among the five SFP episodes across the four study groups by MANOVA. Mixed effects modelling was used to estimate the contributing effects of the study groups and maternal responsiveness on infant affect.

RESULTS

Maternal contingent responding was associated with increase (β̂=0.84; p<0.0001) and attention seeking with decrease (β̂=-0.78; p<0.0001) in infant positive affect. The combined effect of prenatal exposures and covariates explained 15.8% of the variability in infant positive affect, while the model including contingent responding and covariates explained 67.1% of the variability.

CONCLUSIONS

Higher maternal responsiveness was a much stronger predictor of infant behavior than prenatal exposures, providing the basis for future intervention studies focusing on specific parenting strategies.

Stability of Phosphatidylethanol in Dry Blood Spot Cards

BACKGROUND

The analysis of phosphatidylethanol, a promising direct ethanol metabolite, in dry blood spots (PEth-DBS) is advantageous due to ease of storage, transportation and minimal invasiveness of capillary blood collection. One potential application of PEth-DBS is to confirm prenatal alcohol exposure in newborns suspected of FASD; however, stability of PEth-DBS is largely unknown.

METHODS

Phlebotomized samples from 31 adults with a history of alcoholism, admitted to the University of New Mexico Emergency Department, were analyzed for blood alcohol content and pipetted onto DBS cards (13 spots per patient). The first spot was analyzed within 2 weeks of collection for a baseline PEth; the remaining 12 spots were allocated into three temperature conditions (room temperature, 4°C, -80°C) for the repeated measures analysis. In addition, 5 newborn DBS samples with a baseline PEth>LOD were obtained from a prospective cohort at UNM and re-analyzed at 4 months after storage at -80°C. A mixed linear model was fitted to examine the effects of temperature, time and temperature-time interaction on PEth degradation over the first 9 months.

RESULTS

The baseline PEth levels were 592.8 ± 86.7 ng/ml and 18.3 ± 4.8 ng/ml in adult and newborn samples, respectively. All DBS samples remained positive in successive samples in all temperature conditions. Results of mixed linear model demonstrated a significant effect of temperature (P < 0.001) on PEth degradation over 9 months.

CONCLUSIONS

PEth-DBS appears to be relatively stable, especially when stored at lower temperatures. These initial results are encouraging and highlight the PEth-DBS potential in retrospective assessment of alcohol exposure.