The opioid epidemic and pregnancy: implications for anesthetic care

Evaluation of a microphysiological human placental barrier model for studying placental drug transfer

Understanding drug transport across the placental barrier is important for assessing the potential fetal drug toxicity and birth defect risks. Current in vivo and in vitro models have structural and functional limitations in evaluating placental drug transfer and toxicity. Microphysiological systems (MPSs) offer more accurate and relevant physiological models of human tissues and organs on a miniature scale for drug development and toxicology testing. MPSs for the placental barrier have been recently explored to study placental drug transfer. We utilized a multilayered hydrogel membrane-based microphysiological model composed of human placental epithelial and endothelial cells to replicate the key structure and function of the human placental barrier. A macroscale human placental barrier model was created using a transwell to compare the results with the microphysiological model. Placental barrier models were characterized by assessing monolayer formation, intercellular junctions, barrier permeability, and their structural integrity. Three small-molecule drugs (glyburide, rifaximin, and caffeine) that are prescribed or taken during pregnancy were studied for their placental transfer. The results showed that all three drugs crossed the placental barrier, with transfer rates in the following order: glyburide (molecular weight, MW = 494 Da) < rifaximin (MW = 785.9 Da) < caffeine (MW = 194.19 Da). Using non-compartmental analysis, we estimated human pharmacokinetic characteristics based on in vitro data from both MPS and transwell models. While further research is needed, our findings suggest that MPS holds potential as an in vitro tool for studying placental drug transfer and predicting fetal exposure, offering insights into pharmacokinetics.

Obstetric pain management for pregnant women with opioid use disorder: A qualitative and quantitative comparison of patient and provider perspectives (QUEST study)

BACKGROUND AND AIM

Patients with opioid use disorder (OUD) may experience inadequate pain management especially during childbirth. This study assessed and compared patient and provider perspectives on analgesia during and after delivery in women with OUD.

DESIGN

Prospective cohort, mixed method design including semi-structured interviews and structured surveys with pregnant or recently pregnant patients (n = 17) and provider (n = 15) groups.

SETTING

Prenatal clinics and hospital postpartum units.

PARTICIPANTS

Patients were pregnant women with OUD currently treated with methadone (n = 1) or buprenorphine (n = 16). Providers were obstetricians (n = 5), obstetric nurses (n = 5) and anesthesiologists (n = 5).

MEASUREMENTS

Validated questionnaires were completed by both groups; patient interviews were conducted during the third trimester and at 5 days post-delivery. Patient topics included pain management preferences, analgesia satisfaction and attitudes toward pain. Provider topics included labor and postpartum pain management perspectives. Interviews were independently coded and qualitatively analyzed for major themes.

FINDINGS

Five major themes emerged from patient interviews: (1) neuraxial blockade was endorsed for labor pain; (2) otherwise, limited pain control options were perceived; (3) no consensus around use of opioids for pain; (4) non-opioid options should be available; and (5) provider communication and health-care system issues act as barriers to adequate pain management. Provider perspective themes included the following: (1) unique challenges in pain management for patients with OUD; (2) confusion on how to plan for and make perinatal adjustments to medication for OUD; (3) discrepant views on use of opioids for pain management; (4) endorsement of non-pharmacological and non-opioid options; and (5) need for improved provider collaboration in developing pain management plans.

CONCLUSIONS

Patients with opioid use disorder and health-care providers prioritize pain management during and after childbirth, but have discrepant views on use of opioids and other pain management options. Inadequate care coordination and discrepancies in opinions need to be addressed both within care teams and between patients and providers. Clinicians would benefit from better evidence to guide clinical care of patients with OUD for patient-centered pain management.

A Systematic Scoping Review of Peridelivery Pain Management for Pregnant People With Opioid Use Disorder: From the Society for Obstetric Anesthesia and Perinatology and Society for Maternal Fetal Medicine

The prevalence of pregnant people with opioid use disorder (OUD), including those receiving medications for opioid use disorder (MOUD), is increasing. Challenges associated with pain management in people with OUD include tolerance, opioid-induced hyperalgesia, and risk for return to use. Yet, there are few evidence-based recommendations for pain management in the setting of pregnancy and the postpartum period, and many peripartum pain management studies exclude people with OUD. This scoping review summarized the available literature on peridelivery pain management in people with OUD, methodologies used, and identified specific areas of knowledge gaps. PubMed and Embase were comprehensively searched for publications in all languages on peripartum pain management among people with OUD, both treated with MOUD and untreated. Potential articles were screened by title, abstract, and full text. Data abstracted were descriptively analyzed to map available evidence and identify areas of limited or no evidence. A total of 994 publications were imported for screening on title, abstracts, and full text, yielding 84 publications identified for full review: 32 (38.1%) review articles, 14 (16.7%) retrospective studies, and 8 (9.5%) case reports. There were 5 randomized controlled trials. Most studies (64%) were published in perinatology (32; 38.1%) journals or anesthesiology (22; 26.2%) journals. Specific areas lacking trial or systematic review evidence include: (1) methods to optimize psychological and psychosocial comorbidities relevant to acute pain management around delivery; (2) alternative nonopioid and nonpharmacologic analgesia methods; (3) whether or not to use opioids for severe breakthrough pain and how best to prescribe and monitor its use after discharge; (4) monitoring for respiratory depression and sedation with coadministration of other analgesics; (5) optimal neuraxial analgesia dosing and adjuncts; and (6) benefits of abdominal wall blocks after cesarean delivery. No publications discussed naloxone coprescribing in the labor and delivery setting. We observed an increasing number of publications on peripartum pain management in pregnant people with OUD. However, existing published works are low on the pyramid of evidence (reviews, opinions, and retrospective studies), with a paucity of original research articles (<6%). Opinions are conflicting on the utility and disutility of various analgesic interventions. Studies generating high-quality evidence on this topic are needed to inform care for pregnant people with OUD. Specific research areas are identified, including utility and disutility of short-term opioid use for postpartum pain management, role of continuous wound infiltration and truncal nerve blocks, nonpharmacologic analgesia options, and the best methods to support psychosocial aspects of pain management.

In vivo pharmacokinetic analyses of placental transfer of three drugs of different physicochemical properties in pregnant rats

Although the use of medication during pregnancy is common, information on exposure to the developing fetus and potential teratogenic effects is often lacking. This study used a rat model to examine the placental transfer of three small-molecule drugs with molecular weights ranging from approximately 300 to 800 Da with different physicochemical properties. Time-mated Sprague Dawley (Hsd:SD) rats aged 11-13 weeks were administered either glyburide, rifaximin, or fentanyl at gestational day 15. Maternal blood, placentae, and fetuses were collected at 5 min, 30 min, 1 h, 4 h, 8 h, 24 h, 48 h, and 96 h post-dose. To characterize the rate and extent of placental drug transfer, we calculated several pharmacokinetic parameters such as maximum concentration (Cmax), time to maximum concentration (Tmax), area under the concentration-time curve (AUC), half-life (t_1/2), clearance (CL), and volume of distribution (Vd) for plasma, placenta, and fetus tissues. The results indicated showed that fetal exposure was lowest for glyburide, accounting for only 2.2 % of maternal plasma exposure as measured by their corresponding AUC ratio, followed by rifaximin (37.9 %) and fentanyl (172.4 %). The fetus/placenta AUC ratios were found to be 10.7 % for glyburide, 11.8 % for rifaximin, and 39.1 % for fentanyl. These findings suggest that although the placenta acts as a protective shield for the fetus, the extent of protection varies for different drugs and depends on factors such as molecular weight, lipid solubility, transporter-mediated efflux, and binding to maternal and fetal plasma proteins.

Post-cesarean gabapentin is not associated with lower opioid consumption or pain scores in women on chronic buprenorphine therapy: A 10-year retrospective cohort study

STUDY OBJECTIVE

To determine if postoperative gabapentin administration is associated with decreased opioid consumption or pain scores following cesarean delivery in women on chronic buprenorphine.

DESIGN

Retrospective cohort study.

SETTING

Postoperative recovery area and postpartum inpatient unit.

PATIENTS

214 women undergoing cesarean delivery while on chronic buprenorphine at a single institution between 2007 and 2017.

INTERVENTIONS

Gabapentin treatment for post-cesarean analgesia.

MEASUREMENTS

The primary outcome was opioid consumption in morphine milligram equivalents, comparing patients who received ≥1 dose of gabapentin within 24 h of cesarean delivery to those who did not. Secondary outcomes included opioid consumption 24-48 and 48-72 h post-cesarean and postoperative numerical rating scale pain scores.

MAIN RESULTS

Of 214 included patients, 64 (30%) received gabapentin while 150 (70%) did not. Gabapentin patients were more likely than controls to have received neuraxial fentanyl (30% vs. 14%, p = 0.01) and transversus abdominis plane block (6% vs. 1%, p = 0.05) and overall received higher doses of ketorolac and acetaminophen. Control patients were more likely to have received neuraxial morphine (78% vs. 90%, p = 0.04) and received higher doses of ibuprofen. In unadjusted analysis, there was no significant difference in morphine milligram equivalent consumption 0-24 h postoperatively between gabapentin (55 mg [IQR 26,84]) and control (53 mg [IQR 28,75]) groups (p = 0.38). After controlling for potential confounders, there remained no significant effect of gabapentin administration (overall effect p = 0.99). Opioid consumption and pain scores were also not significantly different at any other time points.

CONCLUSIONS

In parturients receiving chronic buprenorphine, inclusion of gabapentin in a multimodal analgesic regimen was not associated with lower opioid consumption or pain scores during the first 72 h after cesarean delivery. Prospective randomized studies are needed to confirm these findings.

Caring for Parturients with Substance Use Disorders

Parturients with substance use disorder require expertise to manage the complexity of intoxication, withdrawal, and chronic use as well as ensure adequate analgesia throughout labor. Opioid use disorder in pregnancy has increased more than 4-fold in the past decade, with a 50-fold geographic variability that now dwarfs other substance use in this population. Understanding not only the medical but also the public health and criminal justice implications of substance use disorder is essential to providing optimal care to this at-risk population.

Indicated Opioids in Pregnancy: Guidance on Providing Comprehensive Care

In modern obstetric practice, providers will encounter patients for whom opioid use in pregnancy is reasonable or even necessary. A "one-size-fits-all" approach to the counseling and management of such patients is misguided. Understanding indications for ongoing opioid use in pregnancy is essential to patient-centered care. Specifically, recognition of the nuanced differences between opioid dependence and opioid use disorder is crucial for appropriate diagnosis, screening for common concurrent conditions, adequately counseling about individualized maternal and perinatal risks, and accurate documentation of diagnoses and medical decision-making. In this paper, we explore the current typical scenarios in which opioid use in pregnancy may be encountered, ongoing opioid prescribing should be considered, and provide a guide for the obstetric provider to navigate the antepartum, intrapartum, and postpartum periods. KEY POINTS: · Opioid use in pregnant and postpartum individuals is not rare.. · Obstetric providers may elect to assume opioid prescribing.. · Obstetric providers are positioned to optimize outcomes for the mother-infant dyad..

Maternal Complications and Prescription Opioid Exposure During Pregnancy: Using Marginal Structural Models

INTRODUCTION

Prescription opioids are frequently used for pain management in pregnancy. Studies examining perinatal complications in mothers who received prescription opioids during pregnancy are still limited.

OBJECTIVES

The aim of this study was to assess the association of prescription opioid use and maternal pregnancy and obstetric complications.

METHODS

This retrospective cohort study with the Rhode Island (RI) Medicaid claims data linked to vital statistics throughout 2008-2015 included pregnant women aged 12-55 years with one or multiple live births. Women were excluded if they had cancer, opioid use disorder, or opioid dispensing prior to but not during pregnancy. Main outcomes included adverse pregnancy and obstetric complications. Marginal Structural Cox Models with time-varying exposure and covariates were applied to control for baseline and time-varying covariates. Analyses were conducted for outcomes that occurred 1 week after opioid exposure (primary) or within the same week as exposure (secondary). Sensitivity studies were conducted to assess the effects of different doses and individual opioids.

RESULTS

Of 9823 eligible mothers, 545 (5.5%) filled one or more prescription opioid during pregnancy. Compared with those unexposed, no significant risk was observed in primary analyses, while in secondary analyses opioid-exposed mothers were associated with an increased risk of cesarean antepartum depression (HR 3.19; 95% CI 1.22-8.33), and cardiac events (HR 9.44; 95% CI 1.19-74.83). In sensitivity analyses, results are more prominent in high dose exposure and are consistent for individual opioids.

CONCLUSIONS

Prescription opioid use during pregnancy is associated with an increased risk of maternal complications.

A case report of a pregnant woman diagnosed with intrahepatic cholangiocarcinoma (ICC) complicated by opioid tolerance

Background

Intrahepatic cholangiocarcinoma (ICC) is a rare form of cancer that has a poor prognosis with a 5-year survival rate for localized disease of approximately 15%.

Case presentation

This is a report of a case of cholangiocarcinoma (CC) diagnosed in pregnancy in a patient with an opioid use disorder. The patient is a 37-year-old G7P2042 who presented at 29 weeks of gestation with acute right upper quadrant pain along with jaundince, and changes to her urine and stool. Her workup revealed CC, a rare diagnosis in pregnancy. Approximately 6 months after the diagnosis of ICC the patient died.

Conclusion

Along with the management of this cancer in pregnancy, this case was further complicated by opioid tolerance and the difficulty in controlling the patient’s pain in pregnancy.

Pain medications during pregnancy: data from the Japan environment and children's study

PURPOSE

Analgesic medication epidemic during pregnancy is an important issue in Western countries. However, no large epidemiological study involving pregnant women with pain and their medication use has been conducted in Japan. This study examined the current situation of medication use for non-cancer pain during the perinatal period in Japan using national cohort data.

METHODS

We analyzed 94,649 pregnant women who completed a self-report questionnaire investigating bodily pain and an interview-based medication use survey. Medication use before and during pregnancy and new medication administration/discontinuation during pregnancy were compared between women with and without pain during pregnancy using multivariable covariance analysis.

RESULTS

Mild pain was reported by 50.4% of pregnant women in the first trimester (survey 1) and 61.8% in the second/third trimester (survey 2). Moderate-to-severe pain was reported by 15.4% of women in survey 1 and 22.4% in survey 2. In survey 1, 6.2% of women used prescribed analgesics and 1.6% used over-the-counter analgesics. In survey 2, prescribed and over the counter analgesics were used by 12.2% and 0.8% of women, respectively. Other pain-related medications were rarely used (< 1.0%). Pregnant women with moderate-to-severe pain showed a lower proportion of discontinuation of analgesics and a higher proportion of new administration of prescription and transdermal analgesics compared with those without pain.

CONCLUSIONS

Although a large proportion of pregnant women experience pain, medication use for pain during pregnancy is low in Japan compared with Western countries (50-60%). Adequate treatment or support may be necessary for pregnant women experiencing pain in Japan.

Anesthesia considerations and post-operative pain management in pregnant women with chronic opioid use

The prevalence of opioid use disorder in pregnancy has escalated markedly in recent years. Chronic opioid use during pregnancy poses several challenges for providing adequate analgesia and anesthesia in the peripartum period. These challenges include the potential for withdrawal, opioid tolerance and opioid-induced hyperalgesia. Here we discuss alterations in analgesic pharmacokinetics and pharmacodynamics that are associated with chronic opioid use. In addition, when treating pain in patients with opioid use disorder it is important to distinguish between different subgroups. In this review, we will discuss practical management strategies for parturients with (1) untreated opioid use disorder, (2) parturients on medication-assisted treatment (methadone, buprenorphine) and (3) patients recovering from opioid use disorder that are currently abstinent. Finally, we offer an overview of non-opioid strategies that may be utilized as part of a multimodal approach to providing optimal analgesia in this patient population.

No longer rare diseases and obstetric anesthesia

PURPOSE OF REVIEW

With new medical technologies and changing life styles, maternal demographics has changes and consequently older and sicker women are becoming pregnant.In this review, we present these different high-risk parturient populations, which were once considered rare for the practicing obstetric anesthesiologist.

RECENT FINDINGS

With lifestyle and medical advances, older and sicker women are getting pregnant. Older women are more prone to pregnancy complications. Cancer survivors are becoming pregnant and more pregnant women are being diagnosed with cancer. Previous neurological and cardiac conditions considered not compatible with pregnancy are now seen more frequently. As the rate of obesity increases so does the rate of obstructive sleep apnea, which is known to be associated with many adverse maternal and neonatal sequalae. Finally, increased use of both opioids and marijuana has led to increased number of pregnant women using these illicit substances.

SUMMARY

Future research and implementation of international guidelines for management of these high-risk parturient population is necessary in order to reduce maternal and neonatal morbidity.