Parturients' assessment of water blocks, pethidine, nitrous oxide, paracervical and epidural blocks in labour

Nitrous Oxide for Labor Analgesia: What We Know to Date

Background: Although nitrous oxide (N₂O) has been used since the 1880s for labor analgesia, its popularity has only recently increased in the United States. In 2011, only 3 centers in the country offered N₂O, but as of 2020, several hundred labor units have adopted its use.

Methods: We reviewed the literature and summarize the mechanism of action, clinical uses, and efficacy of N₂O for labor analgesia, as well as patient satisfaction related to its use.

Results: N₂O has several proposed mechanisms of action that make it a viable option for all 3 stages of labor and postpartum procedures. N₂O has been shown to be a safe option for both mom and baby during labor and delivery. Studies support N₂O as an analgesic for laboring. Even though 40% to 60% of women who use N₂O convert to a labor epidural analgesia, satisfaction surveys indicate that analgesia is not the only factor contributing to the use of N₂O during labor.

Conclusion: The use of N₂O has increased in labor and delivery units across the United States since 2011. Despite inferior analgesic properties compared to epidural analgesia, N₂O offers a safe alternative for many parturients who want a greater sense of control and mobility.

Caesarean delivery rates and analgesia effectiveness following injections of sterile water for back pain in labour: A multicentre, randomised placebo controlled trial

BACKGROUND

About a third of women experience severe back pain during labour. Injecting small volumes of intracutaneous sterile water into the lumbar region can be used to relieve this pain, however the procedure is controversial and previous reviews call for high quality trials to establish efficacy. We evaluated the impact on birth outcomes and analgesic effects of sterile water injections.

METHODS

A multicentre, double-blind trial undertaken between December 2012 and December 2017 in one British and 15 Australian maternity units. Women experiencing severe back-pain in labour were assigned (1:1) by an independently generated randomisation schedule stratified by site to injections of either sterile water or saline placebo. Participants and caregivers were blinded to group allocation. The primary outcome was caesarean delivery rate. Main secondary outcomes included at least 30% or 50% reduction in self-reported pain scores at 30, 60 and 90 minutes after treatment. Intention to treat analysis were used and the level of significance for the multiple clinical outcomes was set at p<0.001 with the Bonferroni correction applied. The study is registered with the ACTRN Registry number, ACTRN1261100022195.

FINDINGS

Between December 9, 2012, and December 15, 2017, 1166 women were recruited and randomised: 587 women received sterile water injections (SWI) and 579 a saline placebo. Seven women in the SWI group and 12 in the placebo group were excluded as consent was not completed, leaving 580 and 567, respectively, included in the analysis. The proportions of caesarean delivery were 17·1% (82 of 580) in the SWI group and 14·8% (82 of 567) in the placebo (RR 1·16, 95% CI 0·88-1.51; p = 0·293). At 30 min post treatment 60·8% (330 of 543) of women in the SWI group reported a 30% reduction in self-reported pain compared to 31·4% (163 of 520) placebo (RR 1·94, 95% CI 1·68-2·24; p=<0·001) and 43·3% (235 of 534) SWI reported a 50% reduction versus 18·1% (94 of 520) placebo (RR 2·39, 95% CI 1·95-2·94; p=<0·001). The analgesic effect of SWI compared to placebo remained significant at 60 and 90 min post-treatment. There were no significant differences in other maternal or neonatal outcomes.

INTERPRETATION

Compared to placebo, injections of sterile water did not reduce rates of caesarean delivery. For the main secondary outcome of pain relief the intervention did result in significantly more women reporting at least 30% and 50% reduction in pain for up to 90 min. Water injections have no effect on birth outcomes though can be an effective treatment for the relief of labour-related back pain.Funded by the National Health and Medical Research Council.

A qualitative analysis of parturients' experiences using nitrous oxide for labor analgesia: It is not just about pain relief

BACKGROUND

A vast majority of women who choose nitrous oxide for labor report high satisfaction despite variable analgesic effectiveness. We analyzed comments provided by women who used nitrous oxide for labor, to identify determinants of satisfaction in this population, and to better understand reasons for continuing with nitrous oxide despite variable analgesic effectiveness.

METHODS

We conducted qualitative content analysis of comments in a quality improvement database of routine follow-up assessments of women who delivered vaginally, using nitrous oxide as the sole labor analgesic. An inductive grounded approach was used and emergent themes and subthemes were identified.

RESULTS

Of 6507 vaginal deliveries over 34 months in 2011-2014, 753 (12%) used nitrous oxide as their sole analgesic. Analysis of 264 clarifying comments yielded six emergent themes. Parturients cited nonanalgesic benefits of nitrous oxide use (relaxation, distraction, focus on breathing), as well as partial analgesic effects that they deemed to be sufficient, or consistent with their expectations. Numerous women described their nitrous oxide experience as consistent with their birth plan, including 14 who equated it with natural childbirth. Several comments described nitrous oxide as a vital component of the parturients' birth experience. Some described using nitrous oxide when neuraxial analgesia was not possible. Side effects were identified, as were difficulties using the apparatus/mask. Analysis highlighted importance of timely administration upon request and attention to technical aspects.

CONCLUSIONS

Among parturients who choose nitrous oxide as their sole labor analgesic, determinants of satisfaction are more variable than previously understood, and extend beyond analgesia.

Epidural versus non-epidural or no analgesia for pain management in labour

BACKGROUND

Epidural analgesia is a central nerve block technique achieved by injection of a local anaesthetic close to the nerves that transmit pain, and is widely used as a form of pain relief in labour. However, there are concerns about unintended adverse effects on the mother and infant. This is an update of an existing Cochrane Review (Epidural versus non-epidural or no analgesia in labour), last published in 2011.

OBJECTIVES

To assess the effectiveness and safety of all types of epidural analgesia, including combined-spinal-epidural (CSE) on the mother and the baby, when compared with non-epidural or no pain relief during labour.

SEARCH METHODS

We searched Cochrane Pregnancy and Childbirth's Trials Register (ClinicalTrials.gov), the WHO International Clinical Trials Registry Platform (ICTRP) (30 April 2017), and reference lists of retrieved studies.

SELECTION CRITERIA

Randomised controlled trials comparing all types of epidural with any form of pain relief not involving regional blockade, or no pain relief in labour. We have not included cluster-randomised or quasi-randomised trials in this update.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion and risks of bias, extracted data and checked them for accuracy. We assessed selected outcomes using the GRADE approach.

MAIN RESULTS

Fifty-two trials met the inclusion criteria and we have included data from 40 trials, involving over 11,000 women. Four trials included more than two arms. Thirty-four trials compared epidural with opioids, seven compared epidural with no analgesia, one trial compared epidural with acu-stimulation, one trial compared epidural with inhaled analgesia, and one trial compared epidural with continuous midwifery support and other analgesia. Risks of bias varied throughout the included studies; six out of 40 studies were at high or unclear risk of bias for every bias domain, while most studies were at high or unclear risk of detection bias. Quality of the evidence assessed using GRADE ranged from moderate to low quality.Pain intensity as measured using pain scores was lower in women with epidural analgesia when compared to women who received opioids (standardised mean difference -2.64, 95% confidence interval (CI) -4.56 to -0.73; 1133 women; studies = 5; I2 = 98%; low-quality evidence) and a higher proportion were satisfied with their pain relief, reporting it to be "excellent or very good" (average risk ratio (RR) 1.47, 95% CI 1.03 to 2.08; 1911 women; studies = 7; I2 = 97%; low-quality evidence). There was substantial statistical heterogeneity in both these outcomes. There was a substantial decrease in the need for additional pain relief in women receiving epidural analgesia compared with opioid analgesia (average RR 0.10, 95% CI 0.04 to 0.25; 5099 women; studies = 16; I2 = 73%; Tau2 = 1.89; Chi2 = 52.07 (P < 0.00001)). More women in the epidural group experienced assisted vaginal birth (RR 1.44, 95% CI 1.29 to 1.60; 9948 women; studies = 30; low-quality evidence). A post hoc subgroup analysis of trials conducted after 2005 showed that this effect is negated when trials before 2005 are excluded from this analysis (RR 1.19, 95% CI 0.97 to 1.46). There was no difference between caesarean section rates (RR 1.07, 95% CI 0.96 to 1.18; 10,350 women; studies = 33; moderate-quality evidence), and maternal long-term backache (RR 1.00, 95% CI 0.89 to 1.12; 814 women; studies = 2; moderate-quality evidence). There were also no clear differences between groups for the neonatal outcomes, admission to neonatal intensive care unit (RR 1.03, 95% CI 0.95 to 1.12; 4488 babies; studies = 8; moderate-quality evidence) and Apgar score less than seven at five minutes (RR 0.73, 95% CI 0.52 to 1.02; 8752 babies; studies = 22; low-quality evidence). We downgraded the evidence for study design limitations, inconsistency, imprecision in effect estimates, and possible publication bias.Side effects were reported in both epidural and opioid groups. Women with epidural experienced more hypotension, motor blockade, fever, and urinary retention. They also had longer first and second stages of labour, and were more likely to have oxytocin augmentation than the women in the opioid group. Women receiving epidurals had less risk of respiratory depression requiring oxygen, and were less likely to experience nausea and vomiting than women receiving opioids. Babies born to women in the epidural group were less likely to have received naloxone. There was no clear difference between groups for postnatal depression, headache, itching, shivering, or drowsiness. Maternal morbidity and long-term neonatal outcomes were not reported.Epidural analgesia resulted in less reported pain when compared with placebo or no treatment, and with acu-stimulation. Pain intensity was not reported in the trials that compared epidural with inhaled analgesia, or continuous support. Few trials reported on serious maternal side effects.

AUTHORS' CONCLUSIONS

Low-quality evidence shows that epidural analgesia may be more effective in reducing pain during labour and increasing maternal satisfaction with pain relief than non-epidural methods. Although overall there appears to be an increase in assisted vaginal birth when women have epidural analgesia, a post hoc subgroup analysis showed this effect is not seen in recent studies (after 2005), suggesting that modern approaches to epidural analgesia in labour do not affect this outcome. Epidural analgesia had no impact on the risk of caesarean section or long-term backache, and did not appear to have an immediate effect on neonatal status as determined by Apgar scores or in admissions to neonatal intensive care. Further research may be helpful to evaluate rare but potentially severe adverse effects of epidural analgesia and non-epidural analgesia on women in labour and long-term neonatal outcomes.

'Tough love': The experiences of midwives giving women sterile water injections for the relief of back pain in labour

OBJECTIVE

To explore midwives' experiences of administering sterile water injections (SWI) to labouring women as analgesia for back pain in labour.

DESIGN

A qualitative study, which generated data through semi-structured focus group interviews with midwives. Data were analysed thematically.

SETTING

Two metropolitan maternity units in Queensland, Australia.

PARTICIPANTS

Eleven midwives who had administered SWI for back pain in labour in a randomised controlled trial.

FINDINGS

Three major themes were identified including: i. SWI, is it an intervention?; ii. Tough love, causing pain to relieve pain; iii. The analgesic effect of SWI and impact on midwifery practice.

KEY CONCLUSIONS

Whilst acknowledging the potential benefits of SWI as an analgesic the midwives in this study described a dilemma between inflicting pain to relieve pain and the challenges encountered in their discussions with women when offering SWI. Midwives also faced conflict when women requested SWI in the face of institutional resistance to its use.

IMPLICATIONS FOR PRACTICE

The procedural pain associated with SWI may discourage some midwives from offering women the procedure, providing women with accurate information regarding the intensity and the brevity of the injection pain and the expected degree of analgesic would assist in discussion about SWI with women.

Should Nitrous Oxide Be Used for Laboring Patients?

Nitrous oxide, long used during labor in Europe, is gaining popularity in the United States. It offers many beneficial attributes, with few drawbacks. Cost, safety, and side effect profiles are favorable. Analgesic effectiveness is highly variable, yet maternal satisfaction is often high among the women who choose to use it. Despite being less effective in treating labor pain than neuraxial analgesic modalities, nitrous oxide serves the needs and preferences of a subset of laboring parturients. Nitrous oxide should, therefore, be considered for inclusion in the repertoire of modalities used to alleviate pain and facilitate effective coping during labor.

Paracervical block as pain treatment during second-trimester medical termination of pregnancy: an RCT with bupivacaine versus sodium chloride

STUDY QUESTION

Can paracervical block (PCB) administered before the onset of pain decrease women's pain experience during second-trimester medical termination of pregnancy (MToP)?

SUMMARY ANSWER

There were no clinically significant differences between groups receiving PCB with bupivacaine or saline with regard to the highest and lowest pain intensity, morphine consumption or induction-to abortion interval.

WHAT IS KNOWN ALREADY

The most common side effect of misoprostol is pain; nevertheless, there are sparse studies in pain and pain treatment during MToP, especially in second-trimester abortion. Pain reported in second-trimester medical abortion is often intense, and peaks when the fetal expulsion occurs.

STUDY DESIGN, SIZE, DURATION

A double-blinded RCT was carried out from May 2012 until April 2015. A power calculation was based on a previous pilot study showing that the proportion of women with severe pain [visual analogue scale (VAS) ≥7] was 63%. A clinically significant reduction was considered to yield 35% with severe pain, and with a power of 80% and significance level of 5% (two-sided) 112 women were needed. Accounting for a 20% drop-out rate, a total of 140 women were needed. The primary outcome, pain intensity measured as any VAS ≥7, was analysed using a generalized estimating equations model. The level of significance was set to P < 0.05 two-sided. A computer generated randomization list with block size of 10 was used. The treatment allocation was placed in a sealed, opaque, envelope and picked consecutively.

PARTICIPANTS/MATERIALS, SETTING, METHODS

A total of 589 women attending a gynaecological clinic had a second-trimester abortion during the study period and 276 were invited to participate. A total of 113 women undergoing abortion from 13 weeks of gestation and above were recruited, of which 55 were randomly allocated to receive a PCB with bupivacaine and 58 a PCB with sodium chloride 1 h after the first dose of misoprostol. The full analysis set (FAS) population was defined as all randomized women that had at least one value for any of the outcomes (n = 102). The per-protocol (PP) population was defined as a subset of the FAS excluding patients with major protocol deviations or without a value for the primary outcome (n = 99). Pain was measured by VAS at misoprostol initiation (baseline) and repeated every 30 min until fetal expulsion. The primary outcome was the highest VAS pain intensity at any time point.

MAIN RESULTS AND THE ROLE OF CHANCE

The highest pain intensity, did not show any differences at a cut-off of VAS ≥7 [risk ratio (RR): 1.1; 95% confidence interval (CI): 0.9-1.5; P = 0.0.292]. In the PP analyses, there were 75% women in the bupivacaine group and 64% in the sodium chloride group with VAS ≥7 (RR: 1.2; 95% CI: 0.9-1.5; P = 0.235). Most women did not experience pain at the misoprostol start, 19 women scored a VAS of >0, ranging from 1 to 4 with a mean of 1.8 and median of 2 (P = 1.000). Immediately prior to PCB, 61 women scored a VAS of >0, from 1 to 10 with a mean of 2.0 and median of 1 (P = 0.771). There was a 48% loss of VAS scores at the time of expulsion and the remaining scores did not differ between groups (RR: 1.5; 95% CI: 0.9-2.5). A subgroup analysis of primipara did not show any difference in highest pain intensity VAS ≥7 (RR: 1.2; 95% CI: 0.9-1.6; P = 0.283). No statistically significant differences were observed between groups with regard to the highest and lowest (P = 553 and 0.182) pain intensity and morphine consumption (P = 0.772). Side effects were reported by 28 women (14 women in each group), with no differences between groups. Most common was nausea and vomiting in connection to morphine injection.

LIMITATIONS, REASONS FOR CAUTION

Nearly 60% of the invited women did not want to participate in the study (fear of needles and fear of receiving the placebo) therefore women who tolerate pain may have been overrepresented in the study population. Data collection was stopped, in error, when 113 participants had been recruited. The loss to follow-up was, however, only 11 women (10%), which was lower than expected but intrinsically the study did not fully reach the intended number of women, which may have influenced the results. In addition, the obstetrical and gynaecological background of participating women differs. The participants were informed that they had a 50% chance of receiving a PCB with active substance, which could theoretically have affected their expectations and pain experience (placebo effect). The frequent attention at VAS scoring and the overall care provided may also have affected the participants in a positive way, and helped women to feel supported and more relaxed during the abortion.

WIDER IMPLICATIONS OF THE FINDINGS

The highest pain intensity was severe (VAS: 7-10) among 65-75% of the participants, as reported for first-trimester medical abortion; however, the maximal pain scores remain high despite the PCB. There is, therefore, a clear need for more optimal pain treatment but only limited data exist on pain treatment during MToP over all gestational lengths. As PCB was well tolerated, did not cause any serious side effects and had no negative impact on the abortion process and efficacy, another approach may be worth exploring, namely PCB given on demand at the onset of painful contractions.

STUDY FUNDING/COMPETING INTERESTS

The study was supported by grants from the Swedish Research Council (grant no: 2012-2844), ALF (Karolinska Institutet - Stockholm County Council, Agreement on Medical Research and Training) funding, the Karolinska Institutet, Stockholm South General Hospital, and Swedish Nurses in the Area of Pain - SSOS together with GlaxoSmithKline. None of the authors have any conflicts of interest.

TRIAL REGISTRATION NUMBER

The trial was registered with ClinicalTrials.gov (identifier: NCT01617564) and The EudraCT (number: 2010-020780-21) and was approved by The Regional Ethical Review Board at Karolinska Institutet (dnr: 2007/1277-31/2 and 2010/410-31/1).

TRIAL REGISTRATION DATE

Clinical trial registration was done in May 2012 before initiation of patient recruitment.

DATE OF FIRST PATIENT'S ENROLMENT

29 May 2012.

Nitrous oxide for the management of labor pain: a systematic review

BACKGROUND

We systematically reviewed evidence addressing the effectiveness of nitrous oxide for the management of labor pain, the influence of nitrous oxide on women's satisfaction with their birth experience and labor pain management, and adverse effects associated with nitrous oxide for labor pain management.

METHODS

We searched the MEDLINE, EMBASE, and Cumulative Index to Nursing and Allied Health Literature (CINAHL) databases for articles published in English. The study population included pregnant women in labor intending a vaginal birth, birth attendees or health care providers who may be exposed to nitrous oxide during labor, and the fetus/neonate.

RESULTS

We identified a total of 58 publications, representing 59 distinct study populations: 2 studies were of good quality, 11 fair, and 46 poor. Inhalation of nitrous oxide provided less effective pain relief than epidural analgesia, but the quality of studies was predominately poor. The heterogeneous outcomes used to assess women's satisfaction with their birth experience and labor pain management made synthesis of studies difficult. Most maternal adverse effects reported in the literature were unpleasant side effects that affect tolerability, such as nausea, vomiting, dizziness, and drowsiness. Apgar scores in newborns whose mothers used nitrous oxide were not significantly different from those of newborns whose mothers used other labor pain management methods or no analgesia. Evidence about occupational harms and exposure was limited.

CONCLUSIONS

The literature addressing nitrous oxide for the management of labor pain includes few studies of good or fair quality. Further research is needed across all of the areas examined: effectiveness, satisfaction, and adverse effects.

Nitrous oxide for labor analgesia: expanding analgesic options for women in the United States

Nitrous oxide (N2O) is a commonly used labor analgesic in many Western countries, but is used infrequently in the United States. The University of California at San Francisco has been offering N2O for labor analgesia for more than 30 years. Vanderbilt University Medical Center recently began offering N2O as an option for pain relief in laboring women. Many women report that N2O provides effective pain relief during labor and argue that it should be made more widely available in the United States. This article discusses the use of N2O for pain management during labor, including its history, properties, clinical indications, and use and environmental safety issues. Practical issues regarding implementation of N2O service in a medical center setting are also discussed.

Epidural versus non-epidural or no analgesia in labour

BACKGROUND

Epidural analgesia is a central nerve block technique achieved by injection of a local anaesthetic close to the nerves that transmit pain and is widely used as a form of pain relief in labour. However, there are concerns regarding unintended adverse effects on the mother and infant.

OBJECTIVES

To assess the effects of all modalities of epidural analgesia (including combined-spinal-epidural) on the mother and the baby, when compared with non-epidural or no pain relief during labour.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 March 2011).

SELECTION CRITERIA

Randomised controlled trials comparing all modalities of epidural with any form of pain relief not involving regional blockade, or no pain relief in labour.

DATA COLLECTION AND ANALYSIS

Two of the review authors independently assessed trials for eligibility, methodological quality and extracted all data. We entered data into RevMan and double checked it for accuracy. Primary analysis was by intention to treat; we conducted subgroup and sensitivity analyses where substantial heterogeneity was evident.

MAIN RESULTS

We included 38 studies involving 9658 women; all but five studies compared epidural analgesia with opiates. Epidural analgesia was found to offer better pain relief (mean difference (MD) -3.36, 95% confidence interval (CI) -5.41 to -1.31, three trials, 1166 women); a reduction in the need for additional pain relief (risk ratio (RR) 0.05, 95% CI 0.02 to 0.17, 15 trials, 6019 women); a reduced risk of acidosis (RR 0.80, 95% CI 0.68 to 0.94, seven trials, 3643 women); and a reduced risk of naloxone administration (RR 0.15, 95% CI 0.10 to 0.23, 10 trials, 2645 women). However, epidural analgesia was associated with an increased risk of assisted vaginal birth (RR 1.42, 95% CI 1.28 to 1.57, 23 trials, 7935 women), maternal hypotension (RR 18.23, 95% CI 5.09 to 65.35, eight trials, 2789 women), motor-blockade (RR 31.67, 95% CI 4.33 to 231.51, three trials, 322 women), maternal fever (RR 3.34, 95% CI 2.63 to 4.23, six trials, 2741 women), urinary retention (RR 17.05, 95% CI 4.82 to 60.39, three trials, 283 women), longer second stage of labour (MD 13.66 minutes, 95% CI 6.67 to 20.66, 13 trials, 4233 women), oxytocin administration (RR 1.19, 95% CI 1.03 to 1.39, 13 trials, 5815 women) and an increased risk of caesarean section for fetal distress (RR 1.43, 95% CI 1.03 to 1.97, 11 trials, 4816 women). There was no evidence of a significant difference in the risk of caesarean section overall (RR 1.10, 95% CI 0.97 to 1.25, 27 trials, 8417 women), long-term backache (RR 0.96, 95% CI 0.86 to 1.07, three trials, 1806 women), Apgar score less than seven at five minutes (RR 0.80, 95% CI 0.54 to 1.20, 18 trials, 6898 women), and maternal satisfaction with pain relief (RR 1.31, 95% CI 0.84 to 2.05, seven trials, 2929 women). We found substantial heterogeneity for the following outcomes: pain relief; maternal satisfaction; need for additional means of pain relief; length of second stage of labour; and oxytocin augmentation. This could not be explained by subgroup or sensitivity analyses, where data allowed analysis. No studies reported on rare but potentially serious adverse effects of epidural analgesia.

AUTHORS' CONCLUSIONS

Epidural analgesia appears to be effective in reducing pain during labour. However, women who use this form of pain relief are at increased risk of having an instrumental delivery. Epidural analgesia had no statistically significant impact on the risk of caesarean section, maternal satisfaction with pain relief and long-term backache and did not appear to have an immediate effect on neonatal status as determined by Apgar scores. Further research may be helpful to evaluate rare but potentially severe adverse effects of epidural analgesia on women in labour and long-term neonatal outcomes.

[Paracervical block in obstetrics]

OBJECTIVE

To review the most recent and relevant issues concerning paracervical block in obstetrics since 1975 when Jägerhorn described the superficial technique that has become a standard.

DATA SOURCES

Extraction from Pubmed database of articles issued from 1975 to 2005.

DATA SELECTION

The collected articles were selected on the basis of the use of the superficial injection method. The more recent data were selected. The keywords were: paracervical, labour, childbirth, and neonate.

DATA SYNTHESIS

Paracervical block (PCB) is routinely used over the world despite the risk of foetal bradycardia. Bradycardia occurring immediately after the performance of block is short lasting. The reports of few cases of foetal or neonatal deaths have caused many physicians to question its safety. The incidence of bradycardia has dramatically decreased (less than 10%) due to the Jägerhorn superficial injection method. In case of healthy neonate the occurrence of bradycardia is harmless but its mechanism is still imprecise. The intensity an duration of analgesia is poor in comparison with epidural anaesthesia. PCB is a viable alternative to epidural in selected cases.

Epidural versus non-epidural or no analgesia in labour

BACKGROUND

Epidural analgesia is a central nerve block technique achieved by injection of a local anaesthetic close to the nerves that transmit pain and is widely used as a form of pain relief in labour. However, there are concerns regarding unintended adverse effects on the mother and infant.

OBJECTIVES

To assess the effects of all modalities of epidural analgesia (including combined -spinal-epidural) on the mother and the baby, when compared with non-epidural or no pain relief during labour.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group Trials Register (June 2005).

SELECTION CRITERIA

Randomised controlled trials comparing all modalities of epidural with any form of pain relief not involving regional blockade, or no pain relief in labour.

DATA COLLECTION AND ANALYSIS

Two of the review authors independently assessed trials for eligibility, methodological quality and extracted all data. Data were entered into RevMan and double checked. Primary analysis was by intention-to-treat; sensitivity analyses excluded trials with > 30% of women receiving un-allocated treatment.

MAIN RESULTS

Twenty-one studies involving 6664 women were included, all but one study compared epidural analgesia with opiates. For technical reasons, data on women's perception of pain relief in labour could only be included from one study which found epidural analgesia to offer better pain relief than non-epidural analgesia (weighted mean difference (WMD) -2.60, 95% confidence interval (CI) -3.82 to -1.38, 1 trial, 105 women). However, epidural analgesia was associated with an increased risk of instrumental vaginal birth (relative risk (RR) 1.38, 95% CI 1.24 to 1.53, 17 trials, 6162 women). There was no evidence of a significant difference in the risk of caesarean delivery (RR 1.07, 95% CI 0.93 to 1.23, 20 trials, 6534 women), long-term backache (RR 1.00, 95% CI 0.89 to 1.12, 2 trials, 814 women), low neonatal Apgar scores at five minutes (RR 0.70, 95% CI 0.44 to 1.10, 14 trials, 5363 women), and maternal satisfaction with pain relief (RR 1.18 95% CI 0.92 to 1.50, 5 trials, 1940 women). No studies reported on rare but potentially serious adverse effects of epidural analgesia.

AUTHORS' CONCLUSIONS

Epidural analgesia appears to be effective in reducing pain during labour. However, women who use this form of pain relief are at increased risk of having an instrumental delivery. Epidural analgesia had no statistically significant impact on the risk of caesarean section, maternal satisfaction with pain relief and long-term backache and did not appear to have an immediate effect on neonatal status as determined by Apgar scores. Further research may be helpful to evaluate rare but potentially severe adverse effects of epidural analgesia on women in labour and long-term neonatal outcomes.

Single-shot spinal block for labour analgesia in multiparous parturients*

BACKGROUND

Intrathecal analgesia (ITA) is effective in late, rapidly progressing labour. In 1998, our hospital implemented the use of single-shot spinal block for pain relief in multiparous parturients. As part of a quality assurance programme, we assessed the analgesic efficacy, obstetric and neonatal outcomes and maternal satisfaction after this form of analgesia now in routine use in our labour ward.

METHODS

Two hundred and twenty-nine consecutive multiparous parturients presenting for vaginal delivery and requesting analgesia were asked to participate in this prospective study. All parturients received our standard ITA: 2.5 mg bupivacaine (1 ml) + 25 microg fentanyl (0.5 ml) inserted via the L2-3 or L3-4 interspace. Routine monitoring included maternal vital signs, uterine contraction and fetal heart rate tracing. Pain scores (visual analogue scale (VAS) 0-10), sensory levels, motor block, side-effects and maternal satisfaction were recorded. Satisfactory analgesia was defined as a decrease in pain scores to three or less within 20 min after injection. The number of parturients requesting additional analgesia and the duration of spinal block (time from injection until request for additional medication after satisfactory analgesia had worn off) were recorded.

RESULTS

Two hundred and nine parturients were included in the study. Satisfactory analgesia was achieved in 153 (73%) parturients. Fifty-five (26%) women requested additional analgesia: 38 (18%) because of unsatisfactory analgesia and 17 (8%) because analgesia ended before delivery. The duration of spinal block was 101 +/- 34 min. Pruritus occurred in 64%, fetal bradycardia in 7% and hypotension in 2% of deliveries. Pain relief was rated excellent by 65%, moderate by 20% and inadequate by 14% of the parturients. One hundred and sixty-nine (81%) women stated that they would like to have spinal analgesia again for pain relief during delivery.

CONCLUSION

The majority of multiparous parturients found ITA adequate for pain relief during delivery. However, modifications are required in terms of improved timing, reliability and duration of analgesia.

Patient-controlled epidural technique improves analgesia for labor but increases cesarean delivery rate compared with the intermittent bolus technique

BACKGROUND

We tested the hypothesis that patient-controlled epidural analgesia for labor (PCEA) provides better analgesia and satisfaction than the intermittent bolus technique (bolus) without affecting the mode of delivery.

METHODS

We randomized 187 parturients to receive labor analgesia using either the PCEA or bolus technique. The PCEA group received a starting bolus of 14 mg of bupivacaine and 60 micro g of fentanyl in a 15-ml volume, followed by a background infusion (bupivacaine 0.08% and fentanyl 2 microg ml(-1)) 5 ml h(-1) with a 5-ml bolus and 15-min lock-out interval. The bolus group received boluses of 20 mg of bupivacaine and 75 micro g of fentanyl in a 15-ml volume.

RESULTS

Parturients in the PCEA group had significantly (P < 0.05-0.01) less pain during the first and second stages of labor. There was no difference in the spontaneous delivery rate between the groups, but the cesarean delivery rate was significantly (P < 0.05) higher (16.3% vs. 6.7%) in the PCEA group than in the bolus group. Bupivacaine consumption was significantly (P < 0.01) higher (11.2 mg h(-1) vs. 9.6 mg h(-1)) and the second stage of labor was significantly (P < 0.01) longer (70 min vs. 54 min) in the PCEA group than in the bolus group. Patient satisfaction was equally good in both groups.

CONCLUSION

The PCEA technique provided better pain relief. This was associated with higher bupivacaine consumption, prolongation of the second stage of labor, and an increased rate of cesarean section.

Parenteral opioids for labor analgesia

Labor pain relief is an important aspect of women's health that has historically been neglected. Epidural analgesia is the only consistently effective method of labor pain relief and has recently undergone substantial improvements to address the concerns of both parturients and obstetric care providers. With increased physician awareness, these recent advances are becoming more widely accepted and routinely available for all laboring parturients. Unfortunately, an increasing number of women are presenting to maternity wards with an absolute contraindication to epidural labor analgesia. The present review will provide an outline of the recent developments in parenteral analgesic options which complement modern epidural analgesic techniques. Protocols for the initiation of "state-of-the-art" parenteral analgesic techniques are provided as a guide to facilitate effective, modern, parenteral labor analgesia.

A high rate of epidural analgesia with bupivacaine-sufentanil is consistent with a low rate of caesarean section and instrumental deliveries

OBJECTIVE

To prospectively evaluate if a high rate of epidural analgesia (EDA) with bupivacaine-sufentanil is consistent with a low rate of caesarean section, instrumental deliveries and dystocia and to evaluate maternal and fetal adverse effects of sufentanil.

STUDY DESIGN

Populations-based prospective descriptive study. A change of EDA from bupivacaine to low dose bupivacaine-sufentanil at the delivery unit of the hospital during 1993 resulted in a marked increase in the rate of EDA. The outcome from the study period (1994-1995) was compared to the outcome during a reference period 1991-1992.

RESULTS

There were no significant differences in the incidence of caesarean section and instrumental delivery for dystocia between the two periods (4.4 and 4.6%). The overall incidence of caesarean section, 9.6% and instrumental deliveries, 6.4% during the study period was lower than or comparable to the national background data (11.1 and 6.8%, respectively) while the EDA rate was markedly higher 37.8 versus 21.9%.

CONCLUSION

A high rate of EDA, using low dose bupivacaine and sufentanil is consistent with a low rate of caesarean section and instrumental deliveries. No apparent negative effects on the neonates or mothers were observed.

Intramuscular opioids for maternal pain relief in labour: a randomised controlled trial comparing pethidine with diamorphine

OBJECTIVE

To compare the pain relief and side effects of intramuscular pethidine with intramuscular diamorphine in labour.

DESIGN

Double-blind randomised controlled trial.

SETTING

The labour ward in a UK teaching hospital.

PARTICIPANTS

Sixty-nine nulliparous women and 64 multiparous women in labour who requested narcotic analgesia and remained undelivered one hour after trial entry.

METHODS

Nulliparous women were randomised to receive either 150 mg intramuscular pethidine or 7.5 mg intramuscular diamorphine. Multiparous women were randomised to receive either 100 mg intramuscular pethidine or 5 mg intramuscular diamorphine. All participants received the anti-emetic prochloroperazine at the same time as the trial drugs.

MAIN OUTCOME MEASURES

Maternal analgesia assessed by a visual analogue score and verbal scales of pain intensity and pain relief, maternal sedation and vomiting, neonatal outcome assessed by Apgar scores and the need for resuscitation.

RESULTS

More women allocated to receiving pethidine than to diamorphine reported slight or no pain relief at 60 minutes after administration of these drugs (P = 0.03). This trend was repeated in most of the other measures for maternal analgesia. There was no difference in maternal sedation, but the incidence of vomiting within 60 minutes was lower for women who received diamorphine (P = 0.02). Pethidine was associated with lower Apgar scores at 1 minute (P < 0.05).

CONCLUSION

Intramuscular diamorphine in labour appears to have some benefits, compared with intramuscular pethidine, but the trial was small and further research, particularly into alternative opioids and long term effects on the infants is still needed.

Bupivacaine 2.5 mg/ml versus bupivacaine 0.625 mg/ml and sufentanil l μg/ml with or without epinephrine 1 μg/ml for epidural analgesia in labour

We have compared three different methods of epidural analgesia in labour, bupivacaine 2.5 mg/ml (group B), bupivacaine 0.625 mg/ml + sufentanil 1 microg/ml (group BS) and bupivacaine 0.625 mg/ml + sufentanil 1 microg/ml + epinephrine 1 microg/ml (group BSE). One hundred and forty parturients with a singleton fetus with cephalic presentation were randomly allocated to one of the three groups. Group BSE had significantly less pain than groups B and BS. Group B had a significantly higher degree of motor blockade assessed on the Bromage scale. Significantly, more women in group B required urinary bladder catheterization than in the two other groups and they also had significantly less urge to push during active delivery. The incidence of mild pruritus was 18% in group BS and 36% in group BSE. The frequency of instrumental delivery and caesarean section was low (12% and 6.4%, respectively) with no significant differences between the groups. All women were highly satisfied with the method of analgesia and 97% would prefer the same kind of pain alleviation at the next delivery. We conclude that epidural analgesia with low-dose bupivacaine and sufentanil is as good an analgesic method as high-dose bupivacaine. Addition of low-dose epinephrine improves the analgesia.

Traditional analgesic agents: are parenteral narcotics passé and do inhalational agents still have a place in labour?

Systemic labour pain treatment with opioids and inhaled nitrous oxide has for many decades frequently been used in medically developed countries. Self-administered nitrous oxide (50% in oxygen) has never gained the same popularity in the USA as in the UK or Scandinavia but the use of opioids, mainly pethidine, has generally been widespread in spite of well-known negative effects on the postnatal adaptation of the newborn. Since the often very intense labour pain seems to respond very poorly even to highly sedating doses of parenteral opioids, their frequent use during delivery and parturition has to be questioned. Self-administered inhalation of nitrous oxide 50% in oxygen also has a limited efficacy for relieving labour pain but because it is mainly devoid of adverse effects on the baby or on the parturient its future use in obstetrics can be defended more easily, either as a sole agent in women with low labour pain scores or in early labour preceding epidural analgesia.

Promising non-narcotic analgesic techniques for labour

Epidural analgesia and spinal analgesia are the most effective techniques for relieving labour pain. Basically, local anaesthetics (i.e. bupivacaine) and opioids (i.e. fentanyl or sufentanil), especially when combined, produce excellent analgesia with minimal motor blockade. However, none of these agents is devoid of side-effects and analgesia remains sometimes imperfect, suggesting that new drugs would be welcome. Adrenalin and clonidine act on a2-adrenoceptors in the spinal cord and both have been found to improve analgesia. These two drugs have already been used in many patients and studies because the absence of neurotoxicity has been well documented. Clonidine looks more attractive, although sedation and hypotension limit its use. Other analgesic drugs are promising alternatives but are still at an experimental or very early clinical stage. Neostigmine and ketamine (without preservative) are not neurotoxic while midazolam neurotoxicity is still controversial. Intravenous remifentanil might prove useful when neuraxial analgesia is contraindicated.

Obstetric outcome following epidural analgesia with bupivacaine-adrenaline 0.25% or bupivacaine 0.125% with sufentanil--a prospective randomized controlled study in 1000 parturients

BACKGROUND

Epidural analgesia (EDA) is the most efficient method for pain relief during labour, but there is still a debate as to whether it interferes with the normal process of delivery. Some authors argue that the incidence of instrumental deliveries, Caesarean section, malrotation and protracted labour is increased in parturients receiving EDA.

METHODS

1000 parturients were prospectively randomized to receive EDA either with a high dose of local anaesthetic (0.25% bupivacaine with adrenaline = HD) or with a low dose (0.125% bupivacaine with sufentanil 10 micrograms = LD).

RESULTS

The incidence of instrumental delivery and Caesarean section and the need for oxytocin was reduced in the LD compared to HD group. The delivery time was similar with HD and LD among primiparous, but decreased significantly among multiparous in the LD group. The incidence of malrotation was low in both groups. The quality of analgesia was equal during the first stage in the 2 groups, but was lower in the LD group during the second stage. More parturients in the LD group ambulated, but this did not affect the incidence of instrumental delivery.

CONCLUSION

It is concluded that a lower dosage of bupivacaine combined with sufentanil in epidural analgesia significantly improves the obstetric outcome as compared to a higher dosage of bupivacaine with adrenaline using intermittent bolus technique.

Intravenous fentanyl PCA during labour

PURPOSE

To evaluate the usefulness of intravenous patient-controlled analgesia (PCA) fentanyl for labour analgesia, its effectiveness for maternal pain and safety for the fetus and newborn.

METHODS

Twenty primigravidas were randomised to receive intravenous PCA fentanyl or epidural analgesia for labour pain. Maternal pain, heart rate and arterial oxyhaemoglobin saturation (SpO2) were monitored. Fetal and neonatal monitoring included cardiotocogram (CTG), APGAR, neurological scoring and static-charge-sensitive bed (SCSB) recording for 12 hr postnatally with ECG and SpO2. Fentanyl concentrations and pH of umbilical artery and vein were analysed.

RESULTS

Initially, epidural analgesia was more effective (P = 0.01), and three patients in the fentanyl group were given epidural due to unsatisfactory pain relief. Overall satisfaction for analgesia did not differ between the groups. Maternal side-effects were more frequent in the fentanyl group (dizziness and tiredness most often, P = 0.0001). Severe side-effects were not reported. In CTG there were no differences between groups. All the newborns were healthy, APGAR and pH were normal. Naloxone was not used. Neurological scoring was similar in both groups. In 12 hr monitoring heart rate, breathing frequency and movement time were similar in both groups, but SpO2 was lower in the fentanyl group (P < 0.001). Umbilical cord fentanyl concentrations were low or beyond the detection limit.

CONCLUSION

Intravenous fentanyl can be used for labour analgesia with the doses reported here as an alternative to epidural analgesia. However, the fetus and neonate must be appropriately monitored. Naloxone and oxygen should be available if neonatal distress occurs.

Maternal expectations and experiences of labour pain and analgesia: a multicentre study of nulliparous women

Six hospitals with large maternity units in five different European countries were involved in this multicentre study. At least 100 primiparae for each country were examined. All mothers received two standardized interviews, one during the last month of pregnancy, and one 24 h after delivery. Maternal expectations and experiences of pain, pain relief, and satisfaction with analgesia and childbirth were assessed by a 100 mm visual analogue scale (VAS). Almost all mothers were seen regularly by an obstetrician or a midwife during pregnancy, had prepared childbirth classes and received antenatal information on labor analgesia techniques. Differences between the five groups were noted in the level of education and socio-economic status. Maternal expectations of labor pain and the answers to the pre-delivery interview varied significantly between the centers, as did maternal knowledge, expectation and ultimate choice of analgesic technique. Generally speaking the level of maternal satisfaction with analgesia and childbirth experience was high; however, epidural analgesia was more effective than other methods of pain relief (P<0.0001). The most satisfied mothers were those who expected more pain, were satisfied with the analgesia received and had good pain relief after analgesia (P<0.001).

Lack of analgesic effect of systemically administered morphine or pethidine on labour pain

OBJECTIVE

To evaluate the true analgesic effect of morphine and pethidine on labour pain.

DESIGN

The analgesic and sedative effects of intravenous morphine or pethidine and their effect on anxiety were compared in a prospective, double-blind, randomised dose-response study.

SETTING

A Stockholm teaching hospital obstetric unit.

PARTICIPANTS

Ten healthy nulliparous parturients in active labour were included in each group.

RESULTS

Even after repeated doses (up to 0.15 mg/kg body weight morphine and up to 1.5 mg/kg body weight pethidine) the findings were uniform, with very high pain scores maintained in each group as assessed with visual analogue scale. The parturients were all significantly sedated and several fell asleep but were awakened by pain during contractions.

CONCLUSION

It is concluded that labour pain is not sensitive to systemically administered morphine or pethidine. These drugs only cause heavy sedation. It therefore seems unethical and medically incorrect to meet parturients' requests for pain relief by giving them sedation. Considering the well documented negative effects on newborn infants we also believe systemic pethidine should be avoided in labour.

The intensity of labor pain in grand multiparas

BACKGROUND

The purpose of the current study was to investigate differences in pain experiences and requirements for pain control in parturients with different birth experience. Previous studies have shown that the labor pain experience is significantly less intense in multiparas than in primiparas and requirements for analgesic treatment have therefore been assumed to be minimal in this group.

METHODS

The pain experience during labor was assessed by 70 consecutive grand multiparas (a minimum of five previous deliveries) compared to that of primiparous (n=70) and II-V parous women (n=70). Pain intensity was repeatedly assessed on a pain intensity scale (0-10) according to the progress of cervical dilatation at the first and second stage of labor.

RESULTS

During the latent phase of cervical dilatation (0-3 cm) grand multiparas had a median pain score of 3 compared to 4 in II-V paras and 6 in primiparas (p<0.001). At the end of the first stage and during the second stage the intensity of pain in grand multiparas was significantly higher compared to that in primiparas (median scores 7 to 8 vs 6 to 7, p<0.05). Epidural blocks were administered to 40% of primiparas, 3% of II-V paras and to no grand multiparas (p<0.0001). Twenty-one percent of grand multiparas rated their pain as intolerable (pain scores 9-10) during the second stage compared to 10% of primiparas (p<0.05%). On the third day after delivery, 47% of grand multiparas regarded their analgesia insufficient.

CONCLUSIONS

The majority of parturients, including grand multiparas, suffered from intense pain during labor. After delivery, a significant number of grand multiparas felt that they had received insufficient pain relief.