See Article, page 970

A large majority of women experiencing childbirth rate their pain as severe1 with a significant proportion reporting persistent pain: up to 20% with scar pain after cesarean delivery and perineal or vaginal pain in up to 6% at 6 months after birth.2 Consequently, prescription of opioids is not uncommon in the postpartum period; however, concerns exist regarding their persistent use, typically estimated at a rate of <2% of those exposed to opioids, depending on the study setting.3 With 3.64 and 4.1 million5 annual births in the United States and European Union, respectively, these numbers translate to a significant burden on the population level in Western countries. Identifying who will be at risk of persistent opioid use after exposure in the postpartum period is an obvious first step to mitigate this burden. However, opioid use patterns––and thus risk of persistent use––vary greatly between countries, necessitating setting-specific risk factor analyses.6 It is in this context that the study by Varney et al7 provides an important addition to the current literature by providing data from Australia in addition to already existing prevalence estimates and risk factor analyses from the United States,8 Denmark,9 and Canada.3 Studying 38,832 women who were dispensed an opioid in the 14 days after discharge after childbirth (over a total of 556,020 women discharged after childbirth) they describe an increasing trend in postpartum opioid prescribing among women discharged after a cesarean delivery (from 9.8%–16.6% in 2012 to 19.5%–21.0% in 2018); no such trends were observed for women discharged after a vaginal birth, generally associated with much less opioid prescribing (1.2%–1.5% in 2012 to 1.4%–1.5% in 2018). Oxycodone (44.8%), codeine (42.1%), and tramadol (12.9%) were most often prescribed. The authors also describe a prevalence of persistent opioid use of 11.4% and 4.3% among women that were dispensed an opioid after a vaginal or cesarean delivery, respectively. Here, persistent opioid use was defined using a previously published definition9: having at least 3 opioid prescriptions filled at any time between 30 and 365 days postdischarge. Finally, Varney et al7 assessed the association between a variety of characteristics and persistent opioid use, and interestingly report that their findings suggest that patient characteristics rather than events that occur at birth are important indicators of risk of persistent opioid use and that “the postpartum period may represent a period of vulnerability for patients with such predisposing conditions.” Also notable was the link between persistent opioid use and affluency of a patient’s residential area (lower risk in more affluent areas), rurality (higher risk in more remote areas), and hospital type (higher risk in public hospitals), suggesting substantial sources of variation in postpartum opioid prescribing. These findings highlight 3 core issues: the need for (1) continued monitoring across settings, (2) more guidance/standardization, and (3) thorough understanding of mechanisms behind postpartum prescription of opioids and subsequent persistent use.

Differences in opioid prescribing across (geographic) settings such as patients’ residential area characteristics likely extend beyond national borders. Indeed, childbirth-related opioid prescribing in the United States, for example,8 has been shown to be much higher––27.0% and 75.7% after vaginal and cesarean deliveries, respectively––compared to the numbers reported by Varney et al7 and those from other Western countries,3,9 a possible consequence of the traditionally different pain management climate in the United States––especially compared to Europe––with historical pressure from professional societies, advocacy groups and industry to treat pain as the “fifth vital sign.” Further emphasizing geographic differences in postpartum opioid prescribing, Peahl et al8 describe decreasing trends in prescription of opioids in the postpartum period while an increasing trend was observed by Varney et al,7 specifically for women discharged after a cesarean delivery. This highlights the need for local contextualizations of observed patterns that may inform location-specific targets for intervention, a process that has been applied, for example, in response to periodic publications of European Perinatal Health reports10 that demonstrated substantial between-country variation in perinatal and maternal outcomes.11 Here, given the profound impact of chronic opioid use––when it occurs––in the lives of these young individuals, despite the low absolute risk, one could argue that opioid prescribing after childbirth should be a target for monitoring in addition to the currently recommended indicators of perinatal and maternal health.12 Here, while some individual European data exist,9 Europe-wide descriptions and comparisons are lacking. Such data are likely to be even more relevant in non-European contexts as according to one informal survey across various European countries opioid prescriptions are infrequently provided after childbirth.13 Indeed, across a statewide quality collaborative (within the United States) Peahl et al12 demonstrated substantial between-hospital variation in postpartum opioid prescribing, largely driven by practitioner- and hospital-level factors, signifying an important role for initiatives that seek to improve opioid stewardship.

Likely related to the aforementioned variation has been the lack of guidance in the context of postpartum opioid prescribing. More specifically, not until recently (2021) has the postpartum pain management guideline from the American College of Obstetricians and Gynecologists14 included some guidance on whether women should be discharged with an opioid prescription after either vaginal or cesarean delivery and, if so, how much should be prescribed. While still lacking some specificity, currently recommended discharge considerations emphasize individualized care and include “…shared decision making with individuals regarding pain management after hospital discharge, incorporating pharmacologic interventions that may include opioids” and “duration of opioid use should be limited to the shortest reasonable course expected for treating acute pain.”14 In contrast, other guidelines such as those from the American Pain Society provide even less guidance15 emphasizing the need for more specific “…recommendations for the safe and effective management of postpartum pain…” as stated by Varney et al.7 Of note, while an active field of research, among women after a cesarean delivery, current evidence does not support the addition of a transversus abdominis plane (TAP) block as an adjunct to standard multimodal therapy that already includes neuraxial opioids.14

Also likely responsible for at least some of the between-study variation in postpartum opioid prescribing and risk of persistent opioid use is the variation in definition of chronic opioid use. While Varney et al7 apply the definition of least 3 opioid prescriptions filled at any time between 30 and 365 days after discharge9 others have defined this as ≥1 additional prescriptions for an opioid within 90 days of the first postpartum prescription and ≥1 subsequent opioid prescriptions in the 91 to 365 days afterward.3,8 While it is unclear to what extent these differences in definitions may impact between-study comparisons, it will be crucial for future monitoring studies to transparently report on (justifications for) operationalized definitions and, where possible, to perform sensitivity analyses to optimize comparisons.

Finally, for findings to be actionable, mechanisms behind patterns of postpartum prescription of opioids (and subsequent risk of persistent use) need to be thoroughly understood. Here, while guidelines emphasize individualized care,14 Peahl et al12––in a US context––found that especially practitioner- and hospital-level (in contrast to patient-level) characteristics were driving variation in opioid prescribing rates (up to 25% explained variation) and to a greater extent the variation in amount of opioids prescribed (up to 52% explained variation). In other words, factors other than those related to patient characteristics (and events at birth) were found to be specifically responsible for postpartum opioid prescribing patterns. This included a measure of hospital culture––the Labor Culture Survey––used as a proxy measure of hospital engagement in promoting quality care across all members of the maternity care team. Findings like these are important as they shed light on potential mechanisms, in this specific case, the potential positive impact of a hospital culture that supports team-based care which may contribute to better postpartum pain management through maximizing nonopioid options and prioritizing optimal pain control. The findings by Varney et al7 support these proposed mechanisms as they also find between-hospital differences in opioid prescribing (public versus private hospitals) in a different continent and explore how this could tie into risk of persistent opioid use. They describe that “…preexisting patient characteristics rather than events that occur at birth are important indicators of persistent opioid use and that the postpartum period may represent a period of vulnerability for patients with such [e.g. history of substance use, mental health diagnoses, and use of certain medicines] predisposing conditions.”7 Again, a greater role for external factors when looking at opioid prescribing and subsequent risk for persistent use, not necessarily factors directly related to the events that occur at birth. The literature on persistent postpartum opioid use is far from complete and will require well-planned qualitative research among all stakeholders involved in maternity care in future studies to further tease out exact mechanisms and how these could inform interventions that optimize postpartum pain control while also minimizing risks.

In summary, Varney et al7 add important information to the current literature on postpartum opioid prescribing and subsequent risk of persistent use in Western countries. Their findings highlight the need for continued monitoring and additional (qualitative) research that may inform and/or refine policies to further optimize postpartum pain control in this group of women for which the postpartum period may represent the first time they will be exposed to an opioid.

DISCLOSURES

Name: Jashvant Poeran, MD, PhD.

Contribution: This author contributed to manuscript conceptualization, initial drafting, and revision.

Name: Chang H. Park, MD.

Contribution: This author contributed to manuscript conceptualization, initial drafting, and revision.

This manuscript was handled by: Michael J. Barrington, MBBS, FANZCA, PhD.

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