Chronic pain after childbirth

Persistent Postpartum Pain - A Somatic and Psychologic Perfect Storm

Persistent postpartum pain is common and has a complex etiology. It has both somatic and psychosocial provoking factors and has both functional and psychological ramifications following childbirth. Pain that limits the functional capacity of a person who has the daunting task to take care of all the demands of managing a growing newborn and infant can have debilitating consequences for several people simultaneously. We will review the incidence of persistent postpartum pain, analyze the risk factors, and discuss obstetric, anesthetic, and psychological tools for prevention and management. Based on the current knowledge, early antenatal screening and management is described as the most likely measure to identify patients at risk for persistent postpartum pain. Such antenatal management should be based on the close collaboration between obstetricians, anesthesiologists, and psychologists to tailor peripartum pain management and psychological support-based individual needs.

Perioperative Analgesia and Patients' Satisfaction in Spinal Anesthesia for Cesarean Section: Fentanyl Versus Morphine

Perioperative analgesia for cesarean section aims to ensure the mother's comfort, facilitate a smooth surgical experience, and promote a successful recovery. One-hundred-ninety patients were enrolled in a randomized double-blind study designed to assess the quality of perioperative analgesia, level of satisfaction, and incidence of adverse reactions in elective cesarean section under spinal anesthesia when fentanyl or morphine was added to bupivacaine. Two treatment groups comprising 173 subjects were compared in the per-protocol analysis: F (fentanyl, standard dose 25 μg) and M (morphine, standard dose 100 μg). Numerical pain scores were recorded perioperatively for 72 h (both at rest and on mobilization), with overall postoperative satisfaction and analgesic-related side effects. The patients in the morphine group had significantly better pain management (Mann-Whitney U test, p < 0.001) and higher level of satisfaction (Mann-Whitney U test, p < 0.001). The latter was related to the greater need for rescue medication in the fentanyl group (OR = 4.396; p = 0.019). On the other hand, fentanyl had significantly fewer non-life-threatening side effects, such as high-intensity pruritus (Mann-Whitney U test, p < 0.001), nausea (OR = 0.324; p = 0.019), vomiting and dizziness upon first mobilization (OR = 0.256; p < 0.001). It remains for future clinical trials to help establish doses that will tilt the scale to one side or the other.

Associations between postpartum pain type, pain intensity and opioid use in patients with and without opioid use disorder: a cross-sectional study

BACKGROUND

Pain is a multidimensional construct. The purpose of this cross-sectional, single-centre study was to evaluate the relationship between postpartum pain type with pain intensity and opioid use in people with and without opioid use disorder (OUD).

METHODS

Postpartum pain type was coded from McGill Pain Questionnaire and Patient-Reported Outcome Measurement Information System (PROMIS) inventories in people with or without OUD after childbirth in a 4-month period. The co-primary outcomes were pain intensity (0-10 scale) and total inpatient oxycodone (mg). Multivariable linear mixed-effects models assessed between- and within-person relationships for pain type (primary predictor) and outcomes.

RESULTS

There were 44 522 unique pain scores and types from 2610 people. Pain types were associated with pain intensity (P<0.001). Between-person comparisons showed affective pain was associated with a small but higher total oxycodone dose (difference 1.04 mg compared with no affective pain, P<0.001). Among people with OUD, within-person comparisons showed that the presence of affective pain resulted in pain scores 1 point higher than when affective pain was not present (P=0.002); between-person comparisons showed that people with affective pain had pain scores 6 points higher (P=0.048). Within-person and between-person comparisons among OUD showed that nociceptive/neuropathic pain was associated with a higher total oxycodone dose (1.6 and 11.4 mg, respectively).

CONCLUSIONS

Postpartum pain type was associated with pain intensity and opioid use. Further research is required to address the multiple dimensions of postpartum pain in people with and without OUD to improve treatment of postpartum pain.

Low-intensity ultrasound promotes uterine involution after cesarean section: the first multicenter, randomized, controlled clinical trial

OBJECTIVE

To evaluate the clinical efficacy and safety of low-intensity ultrasound (LIUS) in promoting uterine involution and relieving postpartum pain.

METHODS

The randomized controlled clinical trial in this study was conducted at five centers in three regions across China from June 2014 to December 2014. A total of 498 subjects were randomly divided into two groups. The LIUS group received ultrasound treatment, and the control group received sham ultrasound treatment. The fundal height and visual analogue scale (VAS) scores of the subjects following cesarean section were recorded separately before and after five treatments. The incidence of adverse events was recorded, while the records on lochia duration were obtained by telephone follow-up. The Full Analysis Set (FAS) comprised all subjects randomized who received at least one treatment. The Per-Protocol Set (PPS) comprised all patients who did not seriously violate the study protocol and had good compliance with complete report forms. Efficacy analyses were performed based on the FAS and PPS. All safety analyses were performed based on the safety set (SS), which included all patients who received at least one treatment.

RESULTS

In the analysis of PPS and FAS, the LIUS group performed better than the control group in reducing the fundal height, shortening the duration of lochia, and relieving postpartum pain, with a significant difference between the two groups (p < 0.0001). In the SS analysis, there were no treatment-related adverse events observed in either group.

CONCLUSIONS

The LIUS therapy is safe and effective, which contributes to uterine involution and the alleviation of postpartum pain.

Are labor pain and birth experience associated with persistent pain and postpartum depression? A prospective cohort study

Background and aims A considerable research-literature focuses on pain during labor and associations with postpartum persistent pain and depression, with findings pointing in various directions. The aim of this study was to examine the role of labor pain and overall birth experience in the development of pain and depression 8 weeks after delivery. Methods The study sample was drawn from the Akershus Birth Cohort. Data from multiple sources were used, including the hospital's birth record (n = 4,391), questionnaire data from gestational week 17 of pregnancy (n = 3,752), 8 weeks postpartum (n = 2,217), and two questions about pain and birth experience asked within 48 h after delivery (n = 1,221). The Edinburgh Postnatal Depression Scale was used to measure postpartum depression, a single question was used to measure persistent pain 8 weeks postpartum, while pain and birth experience were measured by numeric rating scales. A history of pre-pregnant depression and chronic pain were measured through self-report questions in gestational week 17. A total of 645 women had complete data from all sources. We applied multiple imputation techniques to handle missing responses on the two questions about pain and birth experience. Results The results showed that neither labor pain nor birth experience were associated with persistent pain 8 weeks postpartum, whereas pain before pregnancy (OR 3.70; 95% CI 2.71-5.04) and a history of depression (OR 2.31; 95% CI 1.85-2.88) were statistically significant predictors of persistent pain. A negative birth experience was significantly (OR 1.16; 95% CI 1.04-1.29) associated with postpartum depression, whereas labor pain intensity was not. A history of depression (OR 3.95; 95% CI 2.92-5.34) and pre-pregnancy pain (OR 2.03; 95% CI 1.37-3.01) were important predictors of postpartum depression 8 weeks after delivery. Conclusions and implications Whilst the relationship between labor pain intensity and postpartum pain and depression remain unclear, our results do imply the need to screen for previous depression and chronic pain conditions in pregnant women, as well as consider preventive measures in those who screen positive.

Neuropathic component of postoperative pain for predicting post-caesarean chronic pain at three months. A prospective observational study

BACKGROUND

Recent investigations have showed that caesarean section (CS) might be a cause of chronic pain, with a consequent decrease in quality of life.

METHODS

Prospective observational study in a Spanish tertiary hospital. Main Outcome measure was to assess early neuropathic characteristics of pain (DN2 score ≥ 3) one week after CS as a potential risk factor for post-caesarean section chronic pain (PCSCP) at three months. Secondary outcome was to identify other risk factors. 610 consecutive consenting patients undergoing CS were interviewed preoperatively, at discharge from recovery room and 24h postoperatively. Telephone follow-up interviews were conducted one week, three months and twelve months following surgery.

RESULTS

We analysed 597 consecutive patients. The incidence of PCSCP at three and twelve postoperative months were 6.2% and 1% respectively. Subjects with NRS score superior to five on movement one week after CS presented higher incidence of PCSCP (NRS superior to five: 19 (52,2%); NRS equal or lower to five: 172 (30,9%); p=0,009). On multivariate analysis neuropathic pain one week after CS was associated with a higher risk of PCSCP (AOR: 1.63 (95% CI: 1.26-2.11; p<0.001). Other identified risk factors for PCSCP were: uterine exteriorization during CS (AOR: 3.89 (95% CI 1.25-12.10; p=0.019) and a lower gestational age (AOR: 0.87 (95% CI: 0.78-0.96; p=0.008).

CONCLUSIONS

Incidence of PCSCP at three and twelve postoperative months was low, 6.2% and 1% respectively. Early neuropathic characteristics of pain after one week measured by neuropathic pain questionnaire, consisting of two questions (DN2) ≥ 3/7 could be used to identify patients at risk for chronic post-surgical pain and develop preventive strategies.

A systematic review of patient-reported outcome measures to assess postpartum pain using Consensus Based Standards for the Selection of Health Measurement Instruments (COSMIN) guidelines

BACKGROUND

We performed a systematic review using Consensus Based Standards for the Selection of Health Measurement Instruments (COSMIN) guidelines to identify the best available patient-reported outcome measure (PROM) of postpartum pain.

METHODS

This review follows COSMIN guidelines. We searched four databases with no date limiters, for previously identified validated PROMs used to assess postpartum pain. PROMs evaluating more than one author-defined domain of postpartum pain were assessed. We sought studies evaluating psychometric properties. An overall rating was then assigned based upon COSMIN analysis, and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach was used to assess the level of evidence for psychometric properties of included PROMs. These assessments were used to make recommendations and identify the best PROM to assess postpartum pain.

RESULTS

We identified 19 studies using seven PROMs (involving 3511 women), which evaluated postpartum pain. All included studies evaluated ≥1 psychometric property of the included PROMs. An adequate number of pain domains was assessed by the Brief Pain Inventory (BPI), Short Form-BPI (SF-BPI), and McGill Pain Questionnaire (MPQ). The SF-BPI was the only PROM to demonstrate adequate content validity and at least a low-level of evidence for sufficient internal consistency, resulting in a Class A recommendation (the best performing instrument, recommended for use).

CONCLUSION

SF-BPI is the best currently available PROM to assess postpartum pain. However, it fails to assess several important domains and only just met the criteria for a Class A recommendation. Future studies are warranted to develop, evaluate, and implement a new PROM designed to specifically assess postpartum pain.

Bilateral posterior Quadratus Lumborum block for pain relief after cesarean delivery: a randomized controlled trial

BACKGROUND

Achieving optimal analgesia with few side effects is the goal of pain management after cesarean delivery. Intrathecal (IT) morphine is the current standard but ultrasound-guided quadratus lumborum block (QLB) may offer superior pain control with fewer side effects. This study compared the pain-free period after cesarean delivery among parturients who received spinal block with IT morphine, with IT morphine and bilateral QLB, or only bilateral QLB.

METHODS

Parturients having elective cesarean delivery under spinal block were randomized and allocated into IT morphine 0.2 mg with sham QLB (Group IT), IT morphine 0.2 mg and bilateral QLB with 0.25% bupivacaine 25 ml in each side (Group IT+QLB), or bilateral QLB with 0.25% bupivacaine 25 ml in each side (Group QLB). A PCA pump was connected after completion of the QLB or sham block. The first time to PCA morphine requirement was recorded and compared.

RESULTS

Eighty parturients were included. Analysis of Group QLB was terminated early because at the second interim analysis, median pain-free period was significantly shorter in Group QLB [hours (95%CI): 2.50 (1.04-3.96) in Group IT vs. 7.75 (5.67-9.83) in IT+QLB vs. 1.75 (0.75-2.75) in QLB (p < 0.001)]. The median (min, max) amount of morphine required during 24 h was 5.5 (0-25) in Group IT vs. 5.0 (0-36) in IT+QLB vs. 17.5 (1-40) mg in Group QLB (p < 0.001). In the final analysis the median pain-free period was 2.50 (1.23-3.77) hours (95%CI) in Group IT (n = 27) vs. 8.02 (5.96-10.07) in IT+QLB (n = 28). (p = 0.027).

CONCLUSION

US-QLB used in conjunction with IT morphine yielded a statistically significant longer median pain-free period compared with standard IT morphine alone. However, QLB alone provided inferior pain control compared with standard IT morphine. When combined with IT morphine, QLB could provide additional analgesic benefit as a part of multimodal analgesic regimen, especially during the early postoperative period.

TRIAL REGISTRATION

ClinicalTrials.gov no. NCT03199170 Date registered on June 22, 2017. Prospectively registered.

Opioid-free multimodal analgesia pathway to decrease opioid utilization after cesarean delivery

AIM

To evaluate an opioid-free multimodal analgesic pathway (MAP) to decrease opioid utilization after cesarean delivery (CD) compared to historic data of our institution prior to using MAP for pain management (pre-MAP).

METHODS

The MAP was implemented in three phases from September 2018 to August 2019. Patients received 1000 mg intravenous (IV) acetaminophen with 30 mg IV ketorolac at 0 (arrival time at recovery room), 6, 12 and 18 h of postoperative course. On the 2nd and the 3rd postoperative days, patients were monitored for pain every 6 h by Numeric Pain Intensity Scale (0 = no pain to 10 = severe pain) and administered 600 mg oral ibuprofen for a pain score between 0 and 4, 600 mg oral ibuprofen and/or 650 mg oral acetaminophen for a pain score between 5-6, 1000 mg IV acetaminophen and/or 30 mg of IV or intramuscular ketorolac for a pain score between 7 and 10. Five milligrams of oral oxycodone was reserved for rescue if all protocol options were exhausted. Patients were discharged with 600 mg oral ibuprofen without opioid prescription. Likert surveys measuring patient satisfaction of pain control were administered during phase 3.

RESULTS

Inpatient and outpatient opioid consumption rates were significantly decreased from 45%, 18% to 23.8%, 8.5% after MAP implementation (P-value <0.001). More than 90% of patients reported that their pain was well controlled and willing to request the same regimen for a future CD.

CONCLUSION

MAP Implementation after CD significantly reduced inpatient and outpatient opioid consumption compared to pre-MAP results while maintaining high patients' satisfaction with pain control.

Quadratus lumborum block vs. transversus abdominis plane block for caesarean delivery: a systematic review and network meta-analysis. Anaesthesia 2020;76:393-403. [PMID: 32621529 DOI: 10.1111/anae.15160]

Caesarean delivery is the most commonly performed inpatient surgical procedure globally. Pain after caesarean delivery is moderate to severe if not adequately treated, and is a primary anaesthetic concern for patients. Transversus abdominis plane and quadratus lumborum blocks are fascial plane blocks that have the potential to improve analgesia following caesarean delivery. Although proponents of the quadratus lumborum block suggest that this technique may provide better analgesia compared with transversus abdominis plane block, there are limited data directly comparing these two techniques. We, therefore, performed a systematic review and network meta-analysis to compare transversus abdominis plane and quadratus lumborum block approaches, seeking randomised controlled trials comparing both techniques to each other, or to control, with or without intrathecal morphine. In all, 31 trials with 2188 patients were included and our primary outcome, the cumulative intravenous morphine equivalent consumption at 24 h, was reported in 12 trials. In the absence of intrathecal morphine, transversus abdominis plane and quadratus lumborum blocks were equivalent, and both were superior to control (moderate-quality evidence). In the presence of intrathecal morphine, no differences were found between control, transversus abdominis plane and quadratus lumborum blocks (moderate-quality evidence). Similar results were found for resting and active pain scores at 4-6 h, 8-12 h, 24 h and 36 h, although quadratus lumborum block was associated with lower pain scores at 36 h when compared with transversus abdominis plane block (very low-quality evidence). However, transversus abdominis plane block was associated with a reduced incidence of postoperative nausea and vomiting (moderate-quality evidence) and sedation when compared with inactive control following intrathecal morphine administration (low-quality evidence). There are insufficient data to draw definitive conclusions, but transversus abdominis plane and quadratus lumborum block appear to be superior to control in the absence of intrathecal morphine, but provide limited additional benefit over inactive control when intrathecal morphine is also used.

Influences of COMT rs4680 and OPRM1 rs1799971 Polymorphisms on Chronic Postsurgical Pain, Acute Pain, and Analgesic Consumption After Elective Cesarean Delivery

OBJECTIVES

The main objectives of this study were to assess the effects of cathechol-O-methyl-transferase (COMT) rs4680 and μ-opioid receptor rs1799971 polymorphisms alone or genotype combinations on chronic postsurgical pain (CPSP), acute pain, and analgesic consumption after elective cesarean delivery in a Chinese cohort.

MATERIALS AND METHODS

Two hundred sixty-six patients undergoing elective cesarean delivery with a Pfannenstiel incision under spinal anesthesia were enrolled in this prospective, observational study. All patients were screened for rs4680 and rs1799971 using a peripheral venous blood sample of DNA. Postoperative pain relief was provided by IV patient-controlled analgesia with sufentanyl and tramadol for 48 hours postoperatively. Postoperative pain scores and analgesic consumption were assessed, and CPSP was evaluated 3 months after surgery in all patients.

RESULTS

Twenty-nine patients (29/266; 10.9%) developed CPSP at 3 months after surgery. The risk factors for CPSP included previous cesarean delivery and higher analgesic consumptions at 24 hours and 48 hours postoperatively (P=0.032, 0.015, and 0.008, reapectively). No associations were found between CPSP and a single rs4680 and rs1799971 polymorphism, or their combinations (P>0.05). In contrast, patients with rs1799971 GG required higher patient-controlled analgesics at 24 hours and 48 hours postoperatively compared with those with other genotypes (GG>AG>AA). However, no significant effects of interactions between the 2 single nucleotide polymorphisms on analgesic consumption were observed.

DISCUSSION

Our results indicate that cathechol-O-methyl-transferase rs4860 and μ-opioid receptor rs1799971 may not contribute to CPSP development after cesarean delivery. The genotype of rs1799971 affects postcesarean analgesic requirement, while the rs4680 do not. Additional larger studies are needed to confirm these findings.

Strategies of analgesic treatment after cesarean delivery. Current state and new alternatives

The number of caesarean sections performed worldwide is increasing, and with it, the need for the optimal analgesia strategies. Deficient postoperative analgesia increases the need for opioids, delays recovery, and is associated with chronic pain and postpartum depression. It is essential to find good postoperative pain control strategies that facilitate early mobility, early recovery, and early hospital discharge with minimal side effects on the mother and infant. Multimodal analgesia based on neuroaxial anaesthesia with morphine in combination with non-opioids such as non-steroidal anti-inflammatory drugs and paracetamol, gives the best post-caesarean analgesia outcome, and allows anaesthesiologists to reserve opioids, corticoids, gabapentin, magnesium or ketamine for situations where neuroaxial anaesthesia cannot be performed, for high-risk patients, or when pain is difficult to control. Peripheral nerve block techniques can also be added, such as transverse abdominis plane block, erector spinae block, or continuous wound infiltration.

Opioid-Free Cesarean Section with Bilateral Quadratus Lumborum Catheters

Introduction

Post-operative pain control following cesarean section delivery (CD) is an important topic of discussion given the lack of consensus on a narcotic-sparing analgesic regimen. We describe the case of an elective CD with narcotic-free pain control using continuous bilateral posterior quadratus lumborum (QL) blockade as the primary mode of analgesia.

Case Report

The patient is a 36-year-old female, G3P1, who presented at 37 weeks of gestation in active labor scheduled for elective primary CD. A spinal anesthetic was performed at L4-L5 with hyperbaric 0.75% bupivacaine, without intrathecal morphine. Bilateral posterior QL catheters were placed under sterile conditions with 20 mL of 0.25% bupivacaine per side. Continuous infusion of 0.2% ropivacaine was then started at 10 mL/hour per side. The patient's pain was controlled with QL catheters and a multimodal pain regimen consisting of non-steroidal anti-inflammatory drugs and acetaminophen. The patient reported a resting pain score of 0 with a dynamic pain score of 3 out of 10 throughout her recovery. She was discharged on post-operative (post-op) day 3 and the catheters were removed without any complications.

Discussion

The gold standard for pain control following CD is intrathecal morphine; however, its use has many adverse effects. Bilateral single-shot QL blocks following CD have been proven to decrease opioid consumption but its limited duration has minimal advantage over intrathecal morphine and patients continue to require oral narcotics for analgesia. With the use of QL catheters and a multimodal pain regimen, it may be possible to achieve opioid-free CD for the post-op period.

AAAPT Diagnostic Criteria for Acute Abdominal and Peritoneal Pain After Surgery

Abdominal and peritoneal pain after surgery is common and burdensome, yet the lack of standardized diagnostic criteria for this type of acute pain impedes basic, translational, and clinical investigations. The collaborative effort among the Analgesic, Anesthetic, and Addiction Clinical Trial Translations, Innovations, Opportunities, and Networks, American Pain Society, and American Academy of Pain Medicine Pain Taxonomy (AAAPT) provides a systematic framework to classify acute painful conditions. Using this framework, a multidisciplinary working group reviewed the literature and developed core diagnostic criteria for acute abdominal and peritoneal pain after surgery. In this report, we apply the proposed AAAPT framework to 4 prototypical surgical procedures resulting in abdominal and peritoneal pain as examples: cesarean delivery, cholecystectomy, colorectal surgical procedures, and pancreas resection. These diagnostic criteria address the 3 most common surgical procedures performed in the United States, capture diverse surgical approaches, and may also be applied to other surgical procedures resulting in abdominal and peritoneal pain. Additional investigation regarding the validity and reliability of this framework will facilitate its adoption in research that advances our comprehension of mechanisms, deliver better treatments, and help prevent the transition of acute to chronic pain after surgery in the abdominal and peritoneal region. PERSPECTIVE: Using AAAPT, we present key diagnostic criteria for acute abdominal and peritoneal pain after surgery. We provide a systematic classification using 5 dimensions for abdominal and peritoneal pain that occurs after surgery, in addition to 4 specific surgical procedures: cesarean delivery, cholecystectomy, colorectal surgical procedures, and pancreas resection.

Neonatal Admission and Its Relationship to Maternal Pain: Pain Scores and Analgesia

The aim of this study was to determine whether postnatal women whose babies required neonatal intensive care unit (NICU) admission self-reported lower pain scores and required less analgesia than women whose babies remained with them. A prospective matched audit comparing pain scores and analgesia requirements where every woman with a baby admitted to the NICU was matched to 2 women whose babies remained on the ward was undertaken. Matches were based on age, number of previous births, type of birth, episiotomy, and epidural or spinal analgesia use. Data were collected on pain scores and analgesia administered in the first 72 hours postbirth. A total of 150 women were recruited and matched from November 2015 to May 2017. No statistically significant differences were found between the 2 groups for opiate analgesia use (P = .91) or pain scores (P = .89). Regardless of NICU admission, significantly higher pain scores were reported in participants who had episiotomies (P = .03). Birth via cesarean birth resulted in significantly higher pain scores (P < .01) and greater opiate administration (P < .01). This study found no statistically significant difference between pain scores or analgesia use of mothers whose babies required NICU admission and mothers whose babies remained with them.

Persistent pain after cesarean delivery

The incidence of persistent pain after cesarean deliveries (CD) varies but is much lower than after comparable surgeries. However, with over four million deliveries annually and a rising CD rate, even a low prevalence of persistent pain after CD impacts many otherwise healthy young women. Consideration of the pathophysiology of persistent pain after surgery and the risk factors predisposing women to persistent and chronic pain after CD provides insights into the prevention and treatment of persistent pain; and improves the quality of care and recovery after CD. The findings that the peripartum state and oxytocin confer protection against persistent pain may provide new and interesting perspectives for the prevention and treatment of chronic pain caused by trauma or surgery. Predictive tools available to identify and target patients at high risk of acute and chronic pain have mostly weak to modest predictive correlations and many are either not clinically feasible or too time-consuming to apply. Persistent pain has been linked to the severity of acute postoperative pain and opioid exposure. Modified surgical techniques, neuraxial anesthesia and opioid-sparing analgesia may help limit the development of persistent and chronic pain. The goal of this narrative review is to examine the incidence of persistent pain after CD; review briefly the underlying pathophysiology of persistent pain and the transition from acute to chronic pain (with particular emphasis on the uniqueness after CD); and to review modifiable risk factors and prevention strategies that identify at-risk patients and allow tailored treatment.

Parturient on Magnesium Infusion and Its Effectiveness as an Adjuvant Analgesic after Cesarean Delivery: A Retrospective Analysis

Background

Perioperative use of intravenous magnesium as part of multimodal analgesia has been increasing in recent years in an effort to decrease the use of opioids. The aim of this study was to evaluate the effectiveness of magnesium sulfate infusion in lowering analgesic requirement and decreasing the intensity of pain score after cesarean delivery.

Methods

Sixty-four patients who underwent cesarean delivery under spinal anesthesia were included in this medical record review: 32 patients received magnesium infusion after cesarean delivery for treatment of mild preeclampsia (Mg group); 32 patients received routine post-cesarean delivery care (control group). Primary outcome was total analgesic consumption and secondary was visual analogue scores (VAS) of pain in each group during the first 24 hours following delivery. These measures were compared using Student's t-tests and Mann-Whitney U-tests.

Results

Our study found that patients in the Mg group had significantly less requirement for analgesia than the control group. In the 24 h after cesarean delivery, the Mg group received significantly less intravenous ketorolac (the standard initial rescue analgesic agent) when compared to the control group (79 ± 23 mg vs. 90 ± 0 mg; P = 0.008). The Mg group also received significantly less intravenous morphine equivalents than the control group (median 5.0 (IRQ: 0.0 - 10.0) vs. 9.3 (IRQ: 6.0 - 21.1); P = 0.001) during the first 24 h after cesarean delivery. The Mg group also had significantly lower VAS pain scores than the control group (median 1.75 (IRQ: 0.4 - 2.6) vs. median 3.2 (IRQ: 2.3 - 4.5); P < 0.001).

Conclusions

Our results suggest that magnesium sulfate infusion decreases total analgesic requirements and lowers VAS pain scores during the first 24 h after cesarean delivery.

Chronic pain during pregnancy: a review of the literature

BACKGROUND AND PURPOSE

The majority of the reviews and studies on chronic pain in pregnancy have primarily focused on the pharmacological and non-pharmacological treatment options. The purpose of our review was to identify evidence-based clinical research for the evaluation and management of preexisting chronic pain in pregnancy, chronic pain associated with pregnancy, and chronic pain in relation to mode of delivery.

METHODS

A literature search was undertaken using the search engines PubMed, CINAHL, EBSCOhost, and Web of Science. Search terms used included "chronic pain" AND "pregnant OR pregnancy" OR "pregnancy complications" from inception through August 2016.

RESULTS

The basis of this review was the 144 articles that met inclusion criteria for this review. Based on our review of the current literature, we recommend 7 guidelines for chronic pain management during and after pregnancy: 1) complete history and physical examination; 2) monitor patients for alcohol, nicotine, and substance use; 3) collaborate with patient to set treatment goals; 4) develop a management plan; 5) for opioids, use lowest effective dose; 6) formulate a pain management plan for labor and delivery; and 7) discuss reproductive health with women with chronic pain.

CONCLUSION

The management of chronic pain associated with pregnancy is understudied. Obstetrical providers primarily manage chronic pain during pregnancy. Some general guidelines are provided for those health care providers until more information is available.

Incidence and severity of chronic pain after caesarean section: A systematic review with meta-analysis

BACKGROUND

The frequency of caesarean section has increased dramatically in recent decades. Despite this, robust data regarding the consequences of caesarean section in terms of developing chronic postsurgical pain (CPSP) are still lacking.

OBJECTIVE

This systematic review analysed the incidence and severity of CPSP in women 3 to less than 6, 6 to less than 12, and at least 12 months after caesarean section.

DESIGN

Systematic review of prospective and retrospective observational studies and randomised controlled trials with meta-analysis.

DATA SOURCE

We searched MEDLINE to May 2015.

ELIGIBILITY CRITERIA

We included all studies investigating the incidence and/or severity of CPSP at least 3 months after caesarean section. The primary outcome was chronic postsurgical wound pain (CPSP 'wound'). Secondary outcomes were persistent pain in the back area, pelvic region or reported as residual pain, and severity of 'birth-related' chronic pain.

RESULTS

Meta-analysis using the random-effects model based on 15 studies (n = 4475) reporting CPSP 'wound' at 3 to less than 6 months after caesarean section revealed an incidence of 15.4% [95% confidence interval (CI): 9.9 to 20.9%]. For 6 to less than 12 and at least 12 months after caesarean section, the incidence of CPSP 'wound' was estimated at 11.5% (95% CI: 8.1 to 15.0%, n = 3345) and 11.2% (95% CI: 7.4 to 15.0%, n = 3451), respectively. Meta-regression analysis using the publication year as predictor revealed stable CPSP 'wound' incidences at each postoperative time slot from 2002 to the present. Of those patients who reported chronic pain, 9.6% (95% CI: 0.0 to 21.0%) had severe pain, 23.5% (95% CI: 10.0 to 37.0%) had moderate pain and 49.2% (95% CI: 18.9 to 79.4%) had mild pain at 6 months.

LIMITATIONS

Major limitations are high statistical heterogeneity of the meta-analyses and inconsistencies in reporting severity of chronic 'birth-related' pain.

CONCLUSION

This meta-analysis finds a clinically relevant incidence of CPSP 'wound' after caesarean section ranging from 15% at 3 months to 11% at 12 months or longer that has been largely stable in recent years.

Pharmacogenetics in obstetric anesthesia

The 21st century has been billed as the era of "precision/personalized medicine." Genetic investigation of clinical syndromes may guide therapy as well as reveal previously unknown biological or pharmacological pathways that may result in novel drug therapies. Several clinical issues in obstetrics and obstetric anesthesiology have been targets for genetic investigations. These include evaluation of the genetic effects on preterm labor and the progression of labor, spinal anesthesia-induced hypotension and the response to medications used to treat hypotension, and the effect of gene variants on pain and analgesic responses. Most studies have examined specific single nucleotide polymorphisms. Findings have revealed modest effects of genetic variation without tangible impact on current clinical practice. Over the next decade, increased availability of whole exome and genome sequencing, epigenetics, large genetic databases, computational biology and other information technology, and more rapid methods of real-time genotyping may increase the impact of genetics in the clinical arena of obstetrics and obstetric anesthesia.

Persistent opioid use following cesarean delivery: patterns and predictors among opioid-naïve women

BACKGROUND

The incidence of opioid-related death in women has increased 5-fold over the past decade. For many women, their initial opioid exposure will occur in the setting of routine medical care. Approximately 1 in 3 deliveries in the United States is by cesarean, and opioids are commonly prescribed for postsurgical pain management.

OBJECTIVE

The objective of this study was to determine the risk that opioid-naïve women prescribed opioids after cesarean delivery will subsequently become consistent prescription opioid users in the year following delivery and to identify predictors for this behavior.

STUDY DESIGN

We identified women in a database of commercial insurance beneficiaries who underwent cesarean delivery and who were opioid naïve in the year prior to delivery. To identify persistent users of opioids, we used trajectory models, which group together patients with similar patterns of medication filling during follow-up, based on patterns of opioid dispensing in the year following cesarean delivery. We then constructed a multivariable logistic regression model to identify independent risk factors for membership in the persistent user group.

RESULTS

A total of 285 of 80,127 (0.36%, 95% confidence interval, 0.32-0.40), opioid-naïve women became persistent opioid users (identified using trajectory models based on monthly patterns of opioid dispensing) following cesarean delivery. Demographics and baseline comorbidity predicted such use with moderate discrimination (c statistic = 0.73). Significant predictors included a history of cocaine abuse (risk, 7.41%; adjusted odds ratio, 6.11, 95% confidence interval, 1.03-36.31) and other illicit substance abuse (2.36%; adjusted odds ratio, 2.78, 95% confidence interval, 1.12-6.91), tobacco use (1.45%; adjusted odds ratio, 3.04, 95% confidence interval, 2.03-4.55), back pain (0.69%; adjusted odds ratio, 1.74, 95% confidence interval, 1.33-2.29), migraines (0.91%; adjusted odds ratio, 2.14, 95% confidence interval, 1.58-2.90), antidepressant use (1.34%; adjusted odds ratio, 3.19, 95% confidence interval, 2.41-4.23), and benzodiazepine use (1.99%; adjusted odds ratio, 3.72, 95% confidence interval, 2.64-5.26) in the year prior to the cesarean delivery.

CONCLUSION

A very small proportion of opioid-naïve women (approximately 1 in 300) become persistent prescription opioid users following cesarean delivery. Preexisting psychiatric comorbidity, certain pain conditions, and substance use/abuse conditions identifiable at the time of initial opioid prescribing were predictors of persistent use.

Birthing postures and birth canal lacerations

OBJECTIVE

This study was performed to assess the differences in the birth canal lacerations following the lateral and fours posture deliveries compared with those following the supine posture deliveries.

METHODS

We examined the birth canal lacerations of our "low risk" pregnant women under the midwife-led delivery care at Japanese Red Cross Katsushika Maternity Hospital between April 2006 and March 2015.

RESULTS

There were 3826, 1754 and 719 women who delivered with supine, lateral and fours postures. The rate of no laceration in the women who delivered with lateral posture was significant lower than that in the women who delivered with supine posture (OR 0.630, 95% CI 0.56-0.71, p < 0.01); however, the incidence of perineal laceration in the women who delivered with lateral posture was significant lower than that in the women who delivered with supine posture (OR 0.856, 95% CI 0.76-0.90, p < 0.01). The incidence of perineal laceration of third- or fourth-degree in the women who delivered with fours posture was significant higher than that in the women who delivered with supine posture (OR 2.28, 95% CI 1.2-4.2, p < 0.01).

CONCLUSION

The current results may be to help for self-determination of birthing postures in prenatal women.

A retrospective study on persistent pain after childbirth in the Netherlands

Reported prevalence rates of persistent postpartum pain (PPP) range from less than 1% to almost 20%. The aim of this study was to examine the prevalence of PPP in a Dutch cohort and to evaluate a possible causal role for specific risk factors on the development of chronic pain after childbirth. A questionnaire was sent to 960 postpartum women approximately 2 years after delivery. Primary outcome was pain that arose from childbirth at follow-up, and secondary outcomes included quality of life (QoL) and Hospital Anxiety and Depression Scale scores. Tested risk factors included mode of labor analgesia, history of negative effect, history of chronic pain, delivery route, parity, and ethnicity. A total of 495 (51.6%) women participated. At a mean time of 2.3 postpartum years, 7.3% of women reported any pain and 6.1% reported significant pain related to the delivery. Compared to spontaneous delivery, cesarean delivery provided protection against persistent pain (odds ratio, 0.12; 95% CI, 0.01–0.63, P<0.05). None of the other risk factors, including remifentanil use for labor pain, were of influence on the prevalence of persistent pain. Women with PPP experienced greater negative effects and had lower QoL scores compared to women without pain. In this cohort of Dutch patients, PPP is a serious problem with a great impact on the physical and mental health of women.

Nitrous oxide persistently alleviates pain hypersensitivity in neuropathic rats: A dose-dependent effect

BACKGROUND

Despite numerous pharmacological approaches, there are no common analgesic drugs that produce meaningful relief for the majority of patients with neuropathic pain. Although nitrous oxide (N2O) is a weak analgesic that acts via opioid-dependent mechanisms, it is also an antagonist of the N-methyl-D-aspartate receptor (NMDAR). The NMDAR plays a critical role in the development of pain sensitization induced by nerve injury.

OBJECTIVE

Using the chronic constriction injury of the sciatic nerve in male rats as a preclinical model of neuropathic pain, the first aim of the present study was to evaluate the lowest N2O concentration and the shortest time of N2O postinjury exposure that would produce persistent relief of neuropathic pain. The second aim was to compare the effects of N2O with gabapentin, a reference drug used in human neuropathic pain relief.

METHODS

Changes in the nociceptive threshold were evaluated using the paw pressure vocalization test in rats.

RESULTS

Among the various N2O concentrations tested, which ranged from 25% to 50%, only 50% N2O single exposure for 1 h 15 min induced a persistent (minimum of three weeks) and significant (60%) reduction in pain hypersensitivity. A single gabapentin dose (75 mg⁄kg to 300 mg⁄kg, intraperitoneally) induced an acute (1 h to 1 h 30 min) dose-dependent effect, but not a persistent effect such as that observed with N2O.

CONCLUSIONS

These preclinical results suggest that N2O is advantageous for long-lasting neuropathic pain relief after sciatic nerve injury compared with other drugs used in humans such as gabapentinoids or NMDAR antagonists. The present preclinical study provides a rationale for developing comparative clinical studies.

Axotomy of tributaries of the pelvic and pudendal nerves induces changes in the neurochemistry of mouse dorsal root ganglion neurons and the spinal cord

Using immunohistochemical techniques, we characterized changes in the expression of several neurochemical markers in lumbar 4-sacral 2 (L4-S2) dorsal root ganglion (DRG) neuron profiles (NPs) and the spinal cord of BALB/c mice after axotomy of the L6 and S1 spinal nerves, major tributaries of the pelvic (targeting pelvic visceral organs) and pudendal (targeting perineum and genitalia) nerves. Sham animals were included. Expression of cyclic AMP-dependent transcription factor 3 (ATF3), calcitonin gene-related peptide (CGRP), transient receptor potential cation channel subfamily V, member 1 (TRPV1), tyrosine hydroxylase (TH) and vesicular glutamate transporters (VGLUT) types 1 and -2 was analysed seven days after injury. L6-S1 axotomy induced dramatic de novo expression of ATF3 in many L6-S1 DRG NPs, and parallel significant downregulations in the percentage of CGRP-, TRPV1-, TH- and VGLUT2-immunoreactive (IR) DRG NPs, as compared to their expression in uninjured DRGs (contralateral L6-S1-AXO; sham mice); VGLUT1 expression remained unaltered. Sham L6-S1 DRGs only showed a small ipsilateral increase in ATF3-IR NPs (other markers were unchanged). L6-S1-AXO induced de novo expression of ATF3 in several lumbosacral spinal cord motoneurons and parasympathetic preganglionic neurons; in sham mice the effect was limited to a few motoneurons. Finally, a moderate decrease in CGRP- and TRPV1-like-immunoreactivities was observed in the ipsilateral superficial dorsal horn neuropil. In conclusion, injury of a mixed visceral/non-visceral nerve leads to considerable neurochemical alterations in DRGs matched, to some extent, in the spinal cord. Changes in these and potentially other nociception-related molecules could contribute to pain due to injury of nerves in the abdominopelvic cavity.

Breastfeeding and pelvic girdle pain: a follow-up study of 10,603 women 18 months after delivery

OBJECTIVE

To study the associations of patterns and duration of breastfeeding with the persistence of pelvic girdle pain 18 months after delivery.

DESIGN

Longitudinal population study.

SETTING

Norway, for the period 1999-2011.

POPULATION

A follow-up of 10 603 women with singleton deliveries in the Norwegian Mother and Child Cohort Study who reported pelvic girdle pain at 0-3 months postpartum.

METHODS

Data were obtained by four self-administered questionnaires and linked to the Medical Birth Registry of Norway.

MAIN OUTCOME MEASURE

Pelvic girdle pain, defined as combined anterior and bilateral posterior pelvic pain, 18 months after delivery.

RESULTS

Eighteen months after delivery, 7.8% of respondents (829/10,603) reported pelvic girdle pain. Breastfeeding patterns at 5 months after delivery were not associated with persistence of pelvic girdle pain. The proportion of women with pelvic girdle pain 18 months after delivery increased as the duration of breastfeeding decreased (test for trend, P < 0.001). The estimated associations attenuated after adjustment for educational level, smoking status, and body mass index, but remained statistically significant for the association between 0 and 2 months of breastfeeding and persistent pelvic girdle pain (adjusted odds ratio 1.34; 95% confidence interval 1.03-1.75). The association of short breastfeeding duration with persistent pelvic girdle pain was only present in women with body mass index ≥25 kg/m(2) .

CONCLUSIONS

Breastfeeding was associated with a small beneficial effect on the recovery process of pelvic girdle pain in women with a body mass index ≥25 kg/m(2) . Among women with pelvic girdle pain, breastfeeding should be encouraged in accordance with the existing child-feeding recommendations.

Transversus abdominis plane block does not improve early or late pain outcomes after Cesarean delivery: a randomized controlled trial

OBJECTIVES

Cesarean delivery is a common surgical procedure with anticipated substantial postoperative pain. The addition of a transversus abdominis plane block (TAPB) to a multimodal analgesic regimen that includes intrathecal morphine may provide improved early pain outcomes and decrease the risk of chronic post-surgical pain. The purpose of this research was to assess the ability of an ultrasound-guided TAPB with low-dose ropivacaine to decrease early postoperative pain, opioid consumption, and risk of developing persistent pain when compared with a placebo block.

METHODS

Eighty-three women were randomly assigned to either a treatment (0.25% ropivacaine) or control group (0.9% saline) in this double-blind trial, and 74 women were included in the final analysis. Ultrasound-guided TAPBs were performed with an injection of 20 mL of study solution per side. The primary outcome measures of this study were: pain at rest and pain after movement measured with a numeric rating scale, results of the Quality of Recovery-40 (QoR-40) questionnaire, and opioid consumption at 24 hr. These were used with an a priori sample size calculation to detect a 30% reduction in pain scores, a 10% improvement in QoR-40 score, and a 50% reduction in opioid consumption. Health quality and physical functioning were assessed using the Short Form 36 (SF-36®) Health Survey at 30 days and six months.

RESULTS

Assessment at 24 hr after Cesarean delivery revealed no clinically important differences between groups in postoperative pain, QoR-40, or opioid consumption. There were no clinically important differences between groups regarding measures of nausea, pruritus, vomiting, urine retention (2, 24, and 48 hr postoperatively), 24-hr QoR-40 sub-dimensions, or the SF-36 Health Survey (30 days and six months postoperatively).

CONCLUSIONS

Ultrasound-guided TAPB did not improve postoperative pain, quality of recovery, or opioid consumption 24 hr following surgery. Similar health and functioning (SF-36) at 30 days and six months were reported by both groups. This trial was registered at ClinicalTrials.gov number: NCT01261637.