Meperidine for uterine dystocia and its effect on duration of labor and neonatal acid-base status: a randomized clinical trial

Pharmacological labour pain interventions: South African midwives' perspective

BACKGROUND

Women of childbearing age feel great about giving birth, but the pain could be excruciating depending on their pain tolerances. Midwives requires obstetrical knowledge and skills such as pain management during labour and safety. We explored midwives' perspectives on the utilisation of pharmacological pain alleviation interventions during labour in selected hospitals in Matjhabeng Municipality, Free State province, South Africa. A qualitative study was undertaken, involving a sample of ten midwives, using a semi-structured interview guide. The interviews were audio-recorded and transcribed verbatim. Tesch's open coding data analysis method was applied to analyse the data. The midwives were restricted to use Pethidine and Phenergan prescribed by doctors for labour pain relief, which disrupted labour pain management and obliged them either to wait for a physician or follow telephone instructions. According to the midwives, women taking Pethidine and Phenergan encountered adverse effects and discomfort. Midwives identified high workload, inadequate personnel, lack of skill and knowledge, lack of medication availability, and lack of infrastructure as the primary challenges of administering pharmacological methods to women in labour. The lack of standing orders, which delays the administration of medications pending a physician's prescription, constituted an additional difficulty. In the instance that Pethidine and Phenergan were unavailable or ineffective for some women, the midwives recommended that women be administered alternative pharmacological pain relievers. They also advocated for institutionalization of pharmacological guidelines allowing them to use their discretion when treating labour pain. Midwives can only utilise a few standardised and regulated pharmacological medications for labour pain management. The midwives' ability to administer pharmacological pain relief during labour was hampered by a high workload burden, insufficient staff, lack of skill and understanding, drug unavailability, and inadequate infrastructure. Midwives advocated for supported guidelines that would allow them to treat labour pain at their discretion. Intersectoral stakeholders are required to improve midwife skills and attitudes. Health facilities need to train and supply analgesics to midwives. Midwives ought to be familiar with pharmacological pain relievers.

Effect of Pethidine Injection on the Duration of Labor and Pregnancy Outcomes: A Retrospective Cohort Study

Background and Objectives: Long and ineffective labor causes hardships for mothers and doctors and increases the rate of cesarean sections and medical comorbidities. Several factors contribute to effective and less painful labor, including maternal age, parity, fetal characteristics, and the medications or procedures that obstetricians use for labor. We aimed to study the factors that affect labor duration and identify those that make labor more effective. Materials and Methods: This retrospective study included 141 patients who underwent normal vaginal deliveries at the Daegu Catholic University Medical Center between April 2013 and April 2022. Among the 141 patients, 44 received pethidine intravenously, 88 received oxytocin intravenously, and 64 received epidural anesthesia. The duration of the active phase and second stage of labor were recorded according to the findings of a manual examination of the cervix and continuous external electronic monitoring. We analyzed maternal and neonatal medical records and performed binomial logistic regression to identify the factors associated with a shorter active phase of labor. The clinical outcomes in mothers and neonates were also evaluated. Results: Among the various clinical factors, multiparity (odds ratio of parity 0.325) and the use of pethidine (odds ratio 2.906) were significantly associated with shortening the active phase of labor to less than 60 min. The use of epidural anesthesia or oxytocin was not significantly associated with reducing the active phase of labor. When patients were divided into two groups based on whether a pethidine injection had been used during labor, the duration of the active phase was shorter in the pethidine injection group than in the control group for both nulliparas and multiparas. No significant differences in the duration of the second stage of labor were observed between the pethidine injection and control groups. There were no significant differences in pregnancy outcomes, including the need for mechanical ventilation of neonates, Apgar scores, neonatal intensive care unit admissions, number of precipitous deliveries, maternal adverse side effects of drugs, or duration of maternal hospitalization between the two groups. Conclusions: Pethidine can be safely administered to women during labor to help reduce the duration of the active phase by promoting dilatation of the cervix and preventing complications that may result from prolonged labor. Pethidine may be helpful, especially for those who cannot receive epidural anesthesia or who cannot afford it. However, large-scale randomized controlled studies are required to evaluate the efficacy and safety of this drug during labor. Furthermore, it would be helpful if various studies were conducted depending on the timing of administration and indications for delivery.

Pethidine in Low Doses versus Dipyrone for Pain Relief in Labor: A Randomized Controlled Trial

OBJECTIVE

 To compare low doses of pethidine with dipyrone in labor analgesia.

METHODS

 In a randomized prospective study conducted by Universidade de Fortaleza, in the state of Ceará, Brazil, between May and December 2016, 200 full-term parturients, with very painful uterine contractions and exhibiting uterine cervix dilatation ≥ 5 cm, were selected to receive a single intravenous dose of either 0.25 mg/kg of pethidine (n = 100) or of 25 mg/kg of dipyrone (n = 100). Pain was assessed using the visual analogue scale. The data were analyzed using the Student t-test, the chi-square test and the likelihood ratio.

RESULTS

 There was a significant improvement in pain in 35% of the parturients. Both drugs presented a similar analgesic effect 1 hour after the intervention (p = 0.692). There was no analgesic effect during the evaluation of the second hour after the intervention with pethidine or dipyrone. There were no adverse effects, such as maternal drowsiness, nausea or vomiting, related to the drugs used.

CONCLUSION

 Pethidine in low doses and dipyrone presented equivalent analgesia during labor.

PUBLIC REGISTRY OF CLINICAL TRIALS

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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.

Electroacupuncture relieves labour pain and influences the spinal dynorphin/κ-opioid receptor system in rats

BACKGROUND

The dynorphin (DYN)/κ-opioid receptor (KOR) system plays a key role in the control of labour pain. Our previous clinical study reported that electroacupuncture (EA) provided intrapartum analgesia, but the underlying mechanisms of action have not been fully elucidated.

AIMS

To observe the effect of EA on labour pain and to explore the underlying mechanisms of action in a rat model.

METHODS

Copulation-confirmed pregnant rats (n=120) were given castor oil to induce labour. Rats remained untreated (control group, n=20) or received either meperidine (an opioid that is commonly used to treat labour pain, n=20) or EA at SP6, LI4, SP6+LI4 or SP10 (four groups, n=20 each). Labour pain was evaluated by the warm water tail-flick test. Serum DYN values were measured by ELISA. Protein and mRNA expression of prodynorphin (PDYN, the precursor protein of DYN) and KOR were analysed by Western blotting and real-time PCR, respectively.

RESULTS

EA treatment at all acupuncture point combinations studied significantly relieved labour pain and increased serum DYN concentrations, to a degree similar to that achieved with meperidine. EA notably enhanced protein expression of KOR and PDYN and mRNA expression in the lumbar spinal cord but not in the cerebral cortex. The size of effect varied by EA group in the order: SP6>LI4>SP6+LI4>SP10 for all parameters measured, indicating differential effects relating to acupuncture point selection/combination.

CONCLUSIONS

The present study indicates that EA relieves labour pain, at least in part, by regulation of the spinal DYN/KOR system in a rat model.