A comparison of intramuscular diamorphine and intramuscular pethidine for labour analgesia: a two‐centre randomised blinded controlled trial

Comparative effects of epidural analgesia and intramuscular morphine on maternal and neonatal outcomes: a retrospective cohort study

BACKGROUND

The global practice of pain management during labor involves the use of epidural analgesia or intramuscular morphine. However, the impact of these methods on maternal and neonatal short-term outcomes remains uncertain.

OBJECTIVE

This study aimed to evaluate the effect of labor exposure to epidural analgesia and intramuscular morphine on neonatal intensive care unit admission rates and other associated maternal and neonatal outcomes such as sepsis, respiratory distress, instrumental delivery, birth trauma, low Apgar score, and chorioamnionitis.

STUDY DESIGN

A study at the Women's Wellness and Research Center in Qatar analyzed 7721 low-risk normal vaginal deliveries from January 2017 to April 2018. Results were analyzed using descriptive and backward stepwise multinomial regression analysis, categorizing outcomes on the basis of pain management during active labor.

RESULTS

Of the 7607 participants in the final sample, 2606 received epidural analgesia, 1338 received intramuscular morphine, 286 received both, and 3304 received neither. Multinomial regression analysis revealed no difference in neonatal intensive care unit admission in the epidural analgesia group or in the intramuscular morphine group compared with the group that received neither intervention. However, the analysis showed a significant association between the combined use of epidural analgesia and intramuscular morphine and neonatal intensive care unit admission due to respiratory depression (adjusted odds ratio, 8.63; 95% confidence interval, 1.07-69.46; P=.04). Moreover, there was a significant association between prolonged duration of the second stage of labor and receiving epidural analgesia alone (adjusted odds ratio, 1.02; 95% confidence interval, 1.01-1.02; P<.001) or the combination of epidural analgesia and intramuscular morphine (adjusted odds ratio, 1.02; 95% confidence interval, 1.01-1.03; P<.001). In addition, the combined use of epidural analgesia and intramuscular morphine was associated with gestational age (adjusted odds ratio, 1.86; 95% confidence interval, 1.19-2.90; P=.01) and infant sex (adjusted odds ratio, 3.72; 95% confidence interval, 1.54-9.01; P=.003). Intramuscular morphine alone was only linked to low Apgar score at 1 minute (adjusted odds ratio, 6.29; 95% confidence interval, 1.33-29.83; P=.02).

CONCLUSION

In low-risk mothers, combining epidural analgesia and intramuscular morphine during labor increases NICU admission risk due to respiratory depression. However, the individual use of either method shows distinct clinical profile. Further research is warranted to enhance understanding and optimize pain management protocols.

Meperidine Compared With Nitrous Oxide for Intrapartum Pain Relief in Multiparous Patients: A Randomized Controlled Trial

OBJECTIVE

To compare the efficacy and adverse effects of intravenous meperidine and inhaled nitrous oxide for intrapartum analgesia in multiparous patients.

METHODS

This randomized controlled trial was conducted in the delivery ward of a university teaching medical center in Afula, Israel. Multiparous patients with term, singleton pregnancies who were in labor were randomized in a 1:1 ratio to 50 mg intravenous meperidine or inhaled nitrous oxide. The primary outcome was pain intensity 20-30 minutes after analgesic administration, measured on a visual analog scale (VAS) from 0 to 10 cm. Secondary outcomes included the need for additional analgesia, labor length, delivery mode, patient satisfaction, and maternal and neonatal adverse effects. To detect a 1-cm (±2.6) difference in VAS score between the groups, 214 total participants were needed to achieve 80% power with an alpha of 0.05.

RESULTS

From August 2016 through May 2019, 214 participants were enrolled. Fourteen were excluded after randomization. Of the 200 analyzed, 102 received nitrous oxide, and 98 received intravenous meperidine. Demographic and obstetric variables were comparable between the two groups. The VAS score 20-30 minutes after analgesic administration did not differ between the groups (7.7±2.3 cm and 7.6±2.7 cm in the nitrous oxide and meperidine groups, respectively, P=.89). There were no significant differences between the groups in the rate of additional analgesic use, labor length, delivery mode, Apgar scores, rate of breastfeeding, patient satisfaction, or maternal and neonatal adverse effects.

CONCLUSION

Pain intensity was comparable in multiparous patients 20-30 minutes after administration of meperidine and nitrous oxide. Adverse effects were also comparable.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02783508.

"We know it's labour pain, so we don't do anything": healthcare provider's knowledge and attitudes regarding the provision of pain relief during labour and after childbirth

BACKGROUND

Most women experience pain during labour and after childbirth. There are various options, both pharmacological and non-pharmacological, available to help women cope with and relieve pain during labour and after childbirth. In low resource settings, women often do not have access to effective pain relief. Healthcare providers have a duty of care to support women and improve quality of care. We investigated the knowledge and attitudes of healthcare providers regarding the provision of pain relief options in a hospital in Moshi, Tanzania.

METHODS

Semi-structured key informant interviews (n = 24) and two focus group discussions (n = 10) were conducted with healthcare providers (n = 34) in Tanzania. Transcribed interviews were coded and codes grouped into categories. Thematic framework analysis was undertaken to identify emerging themes.

RESULTS

Most healthcare providers are aware of various approaches to pain management including both pharmacological and non-pharmacological options. Enabling factors included a desire to help, the common use of non-pharmacological methods during labour and the availability of pharmacological pain relief for women who have had a Caesarean section. Challenges included shortage of staff, lack of equipment, no access to nitrous oxide or epidural medication, and fears regarding the effect of opiates on the woman and/or baby. Half of all healthcare providers consider labour pain as 'natural' and necessary for birth and therefore do not routinely provide pharmacological pain relief. Suggested solutions to increase evidence-based pain management included: creating an enabling environment, providing education, improving the use of available methods (both pharmacological and non-pharmacological), emphasising the use of context-specific protocols and future research to understand how best to provide care that meets women's needs.

CONCLUSIONS

Many healthcare providers do not routinely offer pharmacological pain relief during labour and after childbirth, despite availability of some resources. Most healthcare providers are open to helping women and improving quality of pain management using an approach that respects women's culture and beliefs. Women are increasingly accessing care during labour and there is now a window of opportunity to adapt and amend available maternity care packages to include comprehensive provision for pain relief (both pharmacological and non-pharmacological) as an integral component of quality of care.

Parenteral opioids for maternal pain management in labour

BACKGROUND

Parenteral opioids (intramuscular and intravenous drugs including patient-controlled analgesia) are used for pain relief in labour in many countries throughout the world. This review is an update of a review first published in 2010.

OBJECTIVES

To assess the effectiveness, safety and acceptability to women of different types, doses and modes of administration of parenteral opioid analgesia in labour. A second objective is to assess the effects of opioids in labour on the baby in terms of safety, condition at birth and early feeding.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register, ClinicalTrials.gov, the WHO International Clinical Trials Registry Platform (ICTRP) (11 May 2017) and reference lists of retrieved studies.

SELECTION CRITERIA

We included randomised controlled trials examining the use of intramuscular or intravenous opioids (including patient-controlled analgesia) for women in labour. Cluster-randomised trials were also eligible for inclusion, although none were identified. We did not include quasi-randomised trials. We looked at studies comparing an opioid with another opioid, placebo, no treatment, other non-pharmacological interventions (transcutaneous electrical nerve stimulation (TENS)) or inhaled analgesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risk of bias, extracted data and checked them for accuracy. We assessed the quality of each evidence synthesis using the GRADE approach.

MAIN RESULTS

We included 70 studies that compared an opioid with placebo or no treatment, another opioid administered intramuscularly or intravenously or compared with TENS applied to the back. Sixty-one studies involving more than 8000 women contributed data to the review and these studies reported on 34 different comparisons; for many comparisons and outcomes only one study contributed data. All of the studies were conducted in hospital settings, on healthy women with uncomplicated pregnancies at 37 to 42 weeks' gestation. We excluded studies focusing on women with pre-eclampsia or pre-existing conditions or with a compromised fetus. Overall, the evidence was graded as low- or very low-quality regarding the analgesic effect of opioids and satisfaction with analgesia; evidence was downgraded because of study design limitations, and many of the studies were underpowered to detect differences between groups and so effect estimates were imprecise. Due to the large number of different comparisons, it was not possible to present GRADE findings for every comparison.For the comparison of intramuscular pethidine (50 mg/100 mg) versus placebo, no clear differences were found in maternal satisfaction with analgesia measured during labour (number of women satisfied or very satisfied after 30 minutes: 50 women; 1 trial; risk ratio (RR) 7.00, 95% confidence interval (CI) 0.38 to 128.87, very low-quality evidence), or number of women requesting an epidural (50 women; 1 trial; RR 0.50, 95% CI 0.14 to 1.78; very low-quality evidence). Pain scores (reduction in visual analogue scale (VAS) score of at least 40 mm: 50 women; 1 trial; RR 25, 95% CI 1.56 to 400, low-quality evidence) and pain measured in labour (women reporting pain relief to be "good" or "fair" within one hour of administration: 116 women; 1 trial; RR 1.75, 95% CI 1.24 to 2.47, low-quality evidence) were both reduced in the pethidine group, and fewer women requested any additional analgesia (50 women; 1 trial; RR 0.71, 95% CI 0.54 to 0.94, low-quality evidence).There was limited information on adverse effects and harm to women and babies. There were few results that clearly showed that one opioid was more effective than another. Overall, findings indicated that parenteral opioids provided some pain relief and moderate satisfaction with analgesia in labour. Opioid drugs were associated with maternal nausea, vomiting and drowsiness, although different opioid drugs were associated with different adverse effects. There was no clear evidence of adverse effects of opioids on the newborn. We did not have sufficient evidence to assess which opioid drug provided the best pain relief with the least adverse effects.

AUTHORS' CONCLUSIONS

Though most evidence is of low- or very-low quality, for healthy women with an uncomplicated pregnancy who are giving birth at 37 to 42 weeks, parenteral opioids appear to provide some relief from pain in labour but are associated with drowsiness, nausea, and vomiting in the woman. Effects on the newborn are unclear. Maternal satisfaction with opioid analgesia was largely unreported. The review needs to be examined alongside related Cochrane reviews. More research is needed to determine which analgesic intervention is most effective, and provides greatest satisfaction to women with acceptable adverse effects for mothers and their newborn.

An Ethical Exploration of Barriers to Research on Controlled Drugs

We examine the ethical, social, and regulatory barriers that may hinder research on therapeutic potential of certain controversial controlled substances like marijuana, heroin, or ketamine. Hazards for individuals and society and potential adverse effects on communities may be good reasons for limiting access and justify careful monitoring of these substances. Overly strict regulations, fear of legal consequences, stigma associated with abuse and populations using illicit drugs, and lack of funding may, however, limit research on their considerable therapeutic potential. We review the surprisingly sparse literature and address the particular ethical concerns pertinent to research with illicit and addictive substances, such as undue inducement, informed consent, therapeutic misconception, and risk to participants, researchers, and institutions. We consider the perspectives of key research stakeholders and explore whether they may be infected with bias. We conclude by proposing an empirical research agenda to provide an evidentiary basis for ethical reasoning.