Antepartum multidisciplinary approach improves postpartum pain scores in patients with opioid use disorder

Introduction

Pregnancies affected by maternal opioid use disorder (OUD) continue to rise in the United States. From 1999 to 2014, the prevalence of pregnancies affected by OUD quadrupled from 1.5 to 6.5 per 1,000 delivery hospitalizations [1], and the rates continue to rise [2]. Although therapeutic opioid medication (methadone and buprenorphine) is effective and increasingly used in maternal OUD populations, knowledge gaps still exist in clinical obstetric care. Acute pain management in this population is particularly nuanced because OUD patients may have opioid tolerance, opioid-induced hyperalgesia, and risk of return to use [2], 3].

Pain perception has multiple dimensions and is influenced by biology, sociocultural, and psychological factors. A previous study investigated over 44,522 unique postpartum pain scores across different pain dimensions from 2,610 OUD patients and controls; results showed that among maternal OUD patients, the presence of affective pain (e.g., emotional pain) resulted in pain scores 1 point higher on the McGill scale than when affective pain was not present, and when compared to controls, a six point difference in pain scores existed in the presence of affective pain [4]. Sensory, cognitive, and affective pain types exist to a greater scale in obstetric OUD patients with significant differences in perception of nociceptive and neuropathic pain postpartum [4], [5], [6].

There is a paucity of research in the optimization of acute pain management around delivery and the postpartum pain experience in women on medication for opioid use disorder (MOUD). The objective of this study is to determine if a multidisciplinary approach for maternal OUD patients affects postpartum pain control. We hypothesized that prenatal consultation with an obstetric anesthesiology provider prior to delivery will decrease severe postpartum pain scores (SPS) in obstetric OUD patients.

Materials and methods

This retrospective cohort study analyzed data from our institution-based electronic record with Institutional Review Board approval (IRB#2022-00228). All pregnancies of persons on MOUD that received prenatal care and delivered at Stony Brook University Hospital between January 2017 and July 2023 were eligible for inclusion. OUD diagnoses followed the criteria as described by The Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-V) [7]. Pregnancies of mothers with OUD not on MOUD and those with incomplete data on postpartum pain (e.g., left against medical advice, postpartum transfers of care) were excluded. For the analyses of all outcomes, exposure was defined as having a prenatal consultation with an obstetric anesthesiologist before delivery. Subjects were divided into those who received prenatal anesthesia consultation and those who did not. Maternal demographics, type of MOUD, and antepartum care utilization were collected. Outcomes abstracted from EMR included the gestational age at delivery; mode of delivery; presence of severe pain (score greater or equal to seven on a numerical pain scale 1–10) and number of severe postpartum pain scores across each postpartum day; postpartum opioid use; postpartum patient-controlled epidural anesthesia (PCEA) use; postpartum OUD relapse, any amount of breast feeding upon newborn’s discharge from the hospital, neonatal opioid withdrawal syndrome (NOWS), and neonatal intensive care unit admission. Statistical analysis was performed using chi-square, Mann–Whitney U, and multivariable logistic regression tests with significance defined as p<0.05 using SPSS software (IBM SPSS Statistics for Macintosh, Version 29.0.1.1. Armonk, NY).

While each anesthesia consultation was individualized for each patient at our institution, we want to highlight the common recommendations from our anesthesia colleagues. For patients attempting a vaginal delivery, anesthesia recommends an early epidural and continuation of MOUD (buprenorphine or methadone) during labor for optimized pain control. Clonidine is used as an adjunct to bupivacaine for epidural labor analgesia and can be considered as alternative to opioids.​ Epidurals are removed immediately postpartum and regular non-steroidal anti-inflammatory drugs (NSAID) pain management is utilized on top of split based dosing of the MOUD. For patient undergoing a cesarean delivery, they receive combined spinal epidural (CSE) anesthesia with 1.6 mL bupivacaine 0.75 % in dextrose in addition to 10 mcg fentanyl and 0.15 mg morphine. This regimen is also used for non-OUD patients undergoing a scheduled cesarean. One major difference is that for maternal OUD patients the epidural catheter is kept active postpartum, usually with a continuous infusion of bupivacaine 0.1 % and clonidine 2 mcg/mL along with a PCEA function. Our regimen is a continuous rate is 7 mL/h, with option for 2 mL PCEA every 20 min for a maximum possible infusion of 13 mL/h. Non-opioid pain medication (e.g., ibuprofen, acetaminophen) is scheduled instead of ordered as needed, along with a multimodal approach utilizing split dose MOUD, gabapentin and muscle relaxers.

Results

The cohort included 359 women on MOUD who received prenatal care and delivered at one institution. Data from our cohort showed 17.8 % (n=64) received anesthesia consultation and 82.2 % (n=295) did not. The cohort of 359 patients was largely Caucasian, had government-assisted insurance, and were less than 35 years old with normal BMIs (Table 1). MOUD type was similar across groups, with the majority of the cohort taking buprenorphine. Active drug use was seen in less than a third of the cohort, did not differ between groups (p=0.16), and was not a significant factor in postpartum pain experience (p=0.87). Factors found to have significant association with prenatal anesthesia consultation were care with obstetric provider with training in maternal opioid care (p<0.001), psychiatric diagnosis (p=0.009) and higher number of prenatal care visits (median 10.0 vs. 9.0, p=0.03) (Table 1).

There was no difference in rate of cesarean delivery, preterm birth, postpartum PCEA use, and inpatient opioid use between those who did and did not receive an antenatal anesthesia consultation, similarly discharge opioid use, postpartum relapse, and any amount of breast feeding at time of discharge were similar between the two groups (Table 2). NOWS diagnoses (both overall and severe NOWS requiring morphine treatment) were not associated with prenatal anesthesia consultation, however NICU admissions were significantly fewer for patients who had anesthesia referral (p=0.002).

When comparing maternal pain scores in the first 24 h postpartum, patients with prenatal anesthesia consultation had significantly lower rates of severe pain scores (SPS) compared to those who did not (25.0 vs. 44.7 %, p=0.01); however, this effect was not sustained after the first 24 h after delivery (Table 3). When looking quantitatively at the number of SPS across postpartum days, anesthesia consultation was associated with lower total number of SPS in the first 24 h after delivery (p=0.008) and on postpartum day three (p=0.049). The distributions for number of SPS with those who received and did not receive antenatal anesthesia consultation is shown in Figure 1. The median number of SPS for those who had an anesthesia consultation was zero across all postpartum days, with ranges of 0–6 # of SPS except for PPD#4 with a range of 0–11. The median number of SPS for those who did not have the consultation was zero across the first 36 h postpartum (ranges 0–15, 0–17, 0–18 respectively) and a median of 1 on PPD#3 and PPD#4 (ranges 0–13, 0–11 respectively). While statistical significance was only found on two postpartum days, across all postpartum days the mean rank for the number of SPS was always higher in the no consultation group: Postpartum Day #0 186.01 vs. 152.31; Postpartum Day #1 182.87 vs. 166.76; Postpartum Day #2 171.16 vs. 150.42; Postpartum Day #3 85.79 vs. 67.78; Postpartum Day #4 54.73 vs. 42.52. In multivariable regression analysis, the independent predictors of SPS in the first 24 h after delivery were anesthesia consultation (OR 0.340; p<0.01) and cesarean delivery (OR 2.81; p<0.01) with psychiatric diagnosis, PCEA use, mode of delivery, and any amount of breast feeding not retaining significance in the model (Table 4).

Figure 1:

Distribution of number of severe pain scores on postpartum day 0 and day 3 by anesthesia consultation.

Discussion

Women experience postpartum pain for a variety of reasons, including uterine involution, hormonal changes, any amount of breast feeding, perineal pain, and/or postoperative pain. It is important to acknowledge the complexity of postpartum pain and investigate interventions that may improve the postpartum experience for patients. In this cohort study that drew from a large database of maternal OUD patients, we observed an association between prenatal obstetric anesthesia consultation and decreased severe range postpartum pain scores in the immediate postpartum time period when pain can be at its peak. This association was regardless of mode of delivery, postpartum opioid use, or PCEA usage.

There is a paucity of literature addressing the efficacy of antenatal anesthesia consultation in reducing postpartum pain scores; however, the recommendation for prenatal anesthesia referral to initiate the process of shared decision-making regarding postpartum prescription opioid use and address concerns regarding pain control has been made in a joint statement by the Society of Maternal-Fetal Medicine, American College of Obstetricians and Gynecologists, and American Society of Addiction Medicine [8]. While this study did not clarify whether the executed anesthesia regimens were different between those that had consultation vs. not, it is possible that preemptive discussion of expectations and individualized consultation may have been a contributor to improvement in postpartum pain scores.

The strengths this study include the large size of the study population. All of our anesthesia consultations were done in the third trimester, often close to delivery, which allows us to link the consultations to the delivery and postpartum pain experience. We looked at both the presence of severe pain postpartum across postpartum hospital days, but also investigated the number of times patients reported severe pain scores, alluding to not just presence but burden of pain. We were also able to see the effect of postpartum pain medication utilization (e.g. opioids and PCEA) on pain scores. Our study has some limitations. Our cohort was restricted to live births to enable linkage of pregnancies to infants and assessment of neonatal outcomes. There may have been factors that were not collected that could affect compliance with recommendation for anesthesia consultation. Logistic restrictions for our patients in terms of access to prenatal anesthesia clinic appointments may have affected compliance. Given that at our institution, outpatient clinics staffed by obstetric anesthesiologists are limited, the number of patients who received an antenatal consultation would not equal the total number of patients. This may have underestimated the effect of multidisciplinary care. The reasoning behind the association of prenatal anesthesia consultation with fewer NICU admissions is uncertain given our hospital does not routinely admit neonates to NICU solely for maternal substance use.

While our study does address early involvement of anesthesiology (i.e., prior to delivery hospitalization), the recommendations for an optimal postpartum pain regimen among subjects with antenatal consultation and decreased pain scores were not uniform, therefore we are unable to comment on a pain management approach. At our institution anesthesia is often involved in the active pain management decisions for postoperative patients in the first 24 h but not usually beyond. While cesarean delivery rates were similar across groups, this may also contribute to the effect of consultation on severe pain scores postpartum.

The results show a significant association between prenatal anesthesia referral and care with obstetric provider with training in opioid care; this aligns with results of a literature review of over 150 articles related to maternal OUD and NOWS [9]. A trauma-informed approach with evidence-based dialogue about opioid use from health care providers improves patient care. Providers with education and experience with maternal OUD patients are trained to recognize particular concerns related to OUD, empathize, and actively avoid re-traumatization. This study found a profound improvement in postpartum pain scores in maternal OUD patients who received antenatal anesthesia consultation. We support a multidisciplinary approach to postpartum pain management for pregnant OUD patients in order to establish an anesthetic plan, address patient concerns, and to improve the postpartum experience through decreased perceived postpartum pain.