The effect of a rapid change in availability of epidural analgesia on the cesarean delivery rate: a meta-analysis

Modern labor epidural analgesia: implications for labor outcomes and maternal-fetal health

Epidural analgesia is an important means of pain control during labor throughout the world. Over its historic development, it has been implicated in several undesirable outcomes, including prolongation of labor and increased need for operative delivery. These effects have emerged in some retrospective and observational studies, but such methods of investigation are highly prone to bias and are particularly ill-suited for the study of labor analgesia. In high-quality studies, including Cochrane reviews and meta-analyses, epidural analgesia has been suggested to extend the first stage of labor by 30 minutes and the second stage by 15 minutes, when compared with alternative forms of analgesia. Although this may be a reproducible effect, it may be argued that it is clinically negligible. With respect to mode of delivery, similar high-quality studies have consistently shown no increased risk of cesarean delivery associated with epidural analgesia. Some forms of epidural analgesia were associated with higher risk of assisted vaginal delivery, but the use of newer modalities has been shown to abolish this effect. Specific advancements have centered on reducing total anesthetic consumption, given that local anesthetic-induced motor block is theorized to interfere with maternal expulsive efforts in the second stage of labor. These measures include the use of low-concentration local anesthetic solutions equivalent to ≤0.1% bupivacaine, shown in meta-analyses to lead to no higher risk of assisted vaginal delivery relative to nonepidural analgesia. Additional advancements in the maintenance of analgesia include programmed intermittent epidural bolus and patient-controlled epidural analgesia, the combination of which has been shown to reduce the risk of assisted vaginal delivery, also likely mediated by reduction in local anesthetic dose. These techniques have gained popularity in the past two decades, such that studies published since 2005 show no higher risk of assisted vaginal delivery with epidural than with opioid analgesia (as reported in a Cochrane review). Labor epidural analgesia has implications for maternal and fetal health perinatally. It is known to result in transient maternal hypotension (particularly with initiation), which may progress to the level of necessitating fluid or vasopressor therapy. This is not clearly associated with any adverse outcomes. There is also a consistently higher incidence of fever in parturients receiving neuraxial anesthesia, likely of noninfectious origin, which has similarly not been associated with adverse neonatal outcomes. Finally, neonates of parturients who receive epidural analgesia have been shown to have no worse Apgar scores and more favorable acid-base status than their counterparts. These observations should serve to reassure providers that modern labor analgesia, as currently understood, is not consistently associated with any significant adverse outcomes for the parturient or fetus. In this review, we describe variations of modern labor epidural analgesia, conduct an in-depth review of current literature on its use, and explore the most up-to-date evidence on its implications for the progression and outcomes of labor, including the pertinent maternal and fetal side effects.

Prolonged Dystocic Labor in Neuraxial Analgesia and the Role of Enkephalin Neurotransmitters: An Experimental Study

The investigation studied the enkephalinergic neuro fibers (En) contained in the Lower Uterine Segment (LUS) during the prolonged dystocic labor (PDL) with Labor Neuraxial Analgesia (LNA). PDL is generally caused by fetal head malpositions in the Occiput Posterior Position (OPP), Persistent Occiput Posterior Position (POPP), in a transverse position (OTP), and asynclitism (A), and it is detected by Intrapartum Ultrasonography (IU). The En were detected in the LUS samples picked up during cesarean section (CS) of 38 patients undergoing urgent CS in PDL, compared to 37 patients submitted to elective CS. Results were statistically evaluated to understand the differences in En morphological analysis by scanning electron microscopy (SEM) and by fluorescence microscopy (FM). The LUS samples analysis showed an important reduction in En in LUS of CS for the PDL group, in comparison with the elective CS group. The LUS overdistension, by fetal head malpositions (OPP, OTP, A) and malrotations, lead to dystocia, modification of vascularization, and En reduction. The En reduction in PDL suggests that drugs used during the LNA, usually local anesthetics and opioids, cannot control the "dystocic pain", that differs from normal labor pain. The IU administration in labor and the consequent diagnosis of dystocia suggest stopping the numerous and ineffective top-up drug administration during LNA, and to shift the labor to operative vaginal delivery or CS.

Association of Epidural Analgesia in Women in Labor With Neonatal and Childhood Outcomes in a Population Cohort

Importance

Although use of epidural analgesia during labor is safe, detailed information about its association with neonatal and child outcomes is limited.

Objective

To investigate the association of labor epidural analgesia with neonatal outcomes and childhood development during the first 1000 days of life.

Design, Setting, and Participants

This population-based cohort study used Scottish National Health Service hospital administrative data of all 435 281 singleton live births in Scotland between January 1, 2007, and December 31, 2016, with follow-up over the first 1000 days of life. All 435 281 mother-infant pairs delivering between 24 weeks 0 days and 43 weeks 6 days' gestation who were in active labor with cephalic presentation and who delivered vaginally or via unplanned cesarean delivery were included. Stillbirths and infants with known congenital anomalies were excluded. Data were analyzed between August 1, 2020, and July 23, 2021.

Exposures

Epidural analgesia in labor.

Main Outcomes and Measures

Neonatal outcomes included resuscitation, Apgar score less than 7 at 5 minutes, and neonatal unit admission. Childhood development measures (gross and fine motor function, communication, and social functioning) were obtained from standardized national childhood surveillance assessments performed at 2 years.

Results

This study included a total of 435 281 live births with cephalic presentation in labor (median gestational age at delivery, 40 weeks [IQR, 39-41 weeks]; 221 153 male infants [50.8%]), of which 94 323 (21.7%) had labor epidural. Epidural analgesia was associated with a reduction in spontaneous vaginal deliveries (confounder-adjusted [Cadj] relative risk [RR], 0.46; 95% CI, 0.42-0.50), an increased risk of neonatal resuscitation (Cadj RR, 1.07; 95% CI, 1.03-1.11), and an increased risk of neonatal unit admission (Cadj RR, 1.14; 95% CI, 1.11-1.17). With additional analysis for mediation by mode of delivery (CMadj), these associations were reversed (CMadj RR, 0.83; 95% CI, 0.79-0.86 for neonatal resuscitation and CMadj RR, 0.94; 95% CI, 0.91-0.97 for neonatal unit admission). Epidural analgesia was associated with a reduced risk of an Apgar score less than 7 at 5 minutes in both confounder and confounder/mediation analyses. Epidural analgesia was associated with a reduced risk of having developmental concern in any domain at 2 years in confounder and confounder/mediation analyses (CMadj RR, 0.96; 95% CI, 0.93-0.98), with specifically fewer concerns regarding communication (CMadj RR, 0.96; 95% CI, 0.93-0.99) and fine motor skills (CMadj RR, 0.89; 95% CI, 0.82-0.97).

Conclusions and Relevance

The results of this cohort study suggest that labor epidural analgesia is not independently associated with adverse neonatal or childhood development outcomes. Associations with neonatal resuscitation and admission were likely mediated by mode of delivery.

The effect of initiating neuraxial analgesia service on the rate of cesarean delivery in Hubei, China: a 16-month retrospective study

BACKGROUND

No Pain Labor &Delivery (NPLD) is a nongovernmental project to increase access to safe neuraxial analgesia through specialized training. This study explores the change in overall cesarean delivery (CD) rate and maternal request CD(MRCD) rate in our hospital after the initiation of neuraxial analgesia service (NA).

METHODS

NA was initiated in May 1st 2015 by the help of NPLD. Since then, the application of NA became a routine operation in our hospital, and every parturient can choose to use NA or not. The monthly rates of NA, CD, MRCD, multiparous women, intrapartum CD, episiotomy, postpartum hemorrhage (PPH), operative vaginal delivery and neonatal asphyxia were analyzed from January 2015 to April 2016.

RESULTS

The rate of NA in our hospital was getting increasingly higher from 26.1% in May 2015 to 44.6% in April 2016 (p < 0.001); the rate of CD was 48.1% (3577/7360) and stable from January to May 2015 (p>0.05), then decreased from 50.4% in May 2015 to 36.3% in April 2016 (p < 0.001); the rate of MRCD was 11.4% (406/3577) and also stable from January to May 2015 (p>0.05), then decreased from 10.8% in May 2015 to 5.7% in April 2016 (p < 0.001). At the same time, the rate of multiparous women remained unchanged during the 16 month of observation (p>0.05). There was a negative correlation between the rate of NA and rate of overall CD, r = - 0.782 (95%CI [- 0.948, - 0.534], p<0.001), and between the utilization rate of NA and rate of MRCD, r = - 0.914 (95%CI [- 0.989, - 0.766], p<0.001). The rates of episiotomy, PPH, operative vaginal delivery and neonatal asphyxia in women who underwent vaginal delivery as well as the rates of intrapartum CD, neonatal asphyxia, and PPH in women who underwent CD remained unchanged, and there was no correlation between the rate of NA and anyone of those rates from January 1st 2015 to April 30th 2016 (p>0.05).

CONCLUSIONS

Our study shows that the rates of CD and MRCD in our department were significantly decreased from May 1st 2015 to April 30th 2016, which may be due to the increasing use of NA during vaginal delivery with the help of NPLD.

A Review of the Impact of Obstetric Anesthesia on Maternal and Neonatal Outcomes

Obstetric anesthesia has evolved over the course of its history to encompass comprehensive aspects of maternal care, ranging from cesarean delivery anesthesia and labor analgesia to maternal resuscitation and patient safety. Anesthesiologists are concerned with maternal and neonatal outcomes, and with preventing and managing complications that may present during childbirth. The current review will focus on recent advances in obstetric anesthesia, including labor anesthesia and analgesia, cesarean delivery anesthesia and analgesia, the effects of maternal anesthesia on breastfeeding and fever, and maternal safety. The impact of these advances on maternal and neonatal outcomes is discussed. Past and future progress in this field will continue to have significant implications on the health of women and children.

Neuraxial techniques of labour analgesia

In recent years, many neuraxial techniques have been introduced to initiate and maintain labour analgesia, with low-dose mixtures of local anaesthetics and opioids, which have improved the quality of analgesia and made it safer for both mother and neonate. An independent search of the databases of PubMed, Medline, and Cochrane controlled trial data was conducted by two researchers, and randomized controlled trials that compared different methods of neuraxial analgesia and the different techniques of maintaining labor analgesia were retrieved and analyzed. The advantages, disadvantages, and indications of each technique along with the doses of intrathecal and epidural drugs are discussed. The myths and controversies involving neuraxial labor analgesia and the current consensus on their effect on the maternal and foetal outcomes are also outlined.

The effect of labor epidural analgesia on maternal-fetal outcomes: a retrospective cohort study

PURPOSE

To evaluate the impact of labor epidural analgesia on maternal-fetal safety outcomes in a signal Chinese academic medical center.

METHODS

A single-intervention impact study was conducted at The Second Affiliated Hospital, Wenzhou Medical University. The study period was divided into three phases: (1) baseline phase: from January 1 and June 30, 2009 when no analgesic method was routinely employed during labor; (2) phase-in period: the epidural analgesia was implemented 8 a.m.-5 p.m. during weekdays; and (3) the post-No Pain Labor N'Delivery phase when the labor epidural was applied 24 h a day, 7 days a week, from June 1, 2010 and June 30, 2011. The maternal-fetal safety outcomes of delivery were compared between the different periods.

RESULTS

There were 15,415 deliveries with 42.3% of nulliparous parturients in the 31-month study period. As the primary outcomes, the labor epidural analgesia rate increased from 0 to 57%, the vaginal delivery rate increased, and cesarean delivery rate decreased by 3.5% after full implementation. As the secondary outcomes, the rate of episiotomy and severe perineal injury after the implementation periods were significant decreased. The rate of postpartum oxytocin administration was decreased by 17.8%. No significant difference between the baseline and implementation periods was found in the rate of postpartum hemorrhage, Apgar scores less than 7 at both 1 and 5 min, 7-day mortality, and the overall neonatal intensive care unit admission rate.

CONCLUSION

Implementation of labor epidural analgesia increased the vaginal delivery rate and use of labor epidural analgesia is safe to parturients and fetus.

Does labour epidural slow the progress of labour and lead to complications? Obstetricians' perception working in private and public sector teaching hospitals in a developing country

Background and Aims:

Obstetricians play a major role in the decision making for provision of analgesia for the woman in labour. As epidural analgesia (EA) is the most preferred technique, it is important to know obstetricians' perception regarding its effect on progress of labour and associated complications.

Methods:

The 6 months cross-sectional study included 114 obstetricians from teaching hospitals. After informed consent, obstetricians were asked to fill a predesigned questionnaire containing 13 close ended questions regarding their perception on the effect of EA on progress of labour, EA complications and whether they would recommend EA to their patients or not. Other variables included age, gender, training in EA, practice type and hospital settings (private or public sector).

Results:

Majority of the obstetricians had the perception of EA prolonging the first stage (89.5%) and second stage (98.2%) of labour, increasing the rate of caesarean section (87.7%), instrumental delivery (58.8%) and increasing the incidence of backache (85.5%). None of the obstetricians received any formal training in EA. Majority (84.2%) were not sure if they would recommend EA to their patients. When these responses were compared between public and private sector, a statistically higher percentage (P < 0.001) of public sector obstetricians had negative perception of EA.

Conclusion:

Perception of obstetrician regarding EA is contrary to the current evidence. There is a need to introduce formal curriculum on EA in obstetric training program and conduct regular refresher courses.

Incidence of cesarean section and analysis of risk factors for failed conversion of labor epidural to surgical anesthesia: A prospective, observational study in a tertiary care center

BACKGROUND AND AIMS

This study aimed to analyze the effect of labor epidural (LE) on the incidence of cesarean section (CS) and assess the risk factors involved in failed conversion of LE to surgical anesthesia for CS.

MATERIAL AND METHODS

A prospective observational study of 18 months from January 2012 to June 2013 was conducted on all patients who had delivered in the labor room suit of our hospital. The data collected for all 4694 patients included their demographics, parity and mode of delivery. In addition a predesigned proforma, with additional information was used for 629 parturient with LE.

RESULTS

During the study period, total numbers of deliveries performed in our hospital were 4694, with an epidural rate of 13.4% (629/4694). No significant difference (P = 0.06) was observed in the rate of CS among women with or without LE (28 % [n = 176/629] vs. 31.7 % [n = 1289/4065]), however, a statistically significant difference (P < 0.01) was observed in the rate of assisted delivery in patients receiving LE as compared to those delivering without it (8.7% [n = 55/629] vs. n = 3.7% [154/4065]). For 176 patients requiring CS, LE utilization for surgical anesthesia was 52.8% (93/176) and factors identified for not utilizing LE in 47% (83/176) were; failure to achieve surgical anesthesia in 6.8% (12/176), emergency CS in 28.4% (50/176), patient preference in 6.8% (12/176) and inadequate labor pain relief with LE in 5.1% (9/176) patients. Non-obstetric anesthesiologists were involved in 59% (49/83) of cases where LE was not used for CS.

CONCLUSION

LE had no effect on the rate of CS; however it significantly increased (P < 0.01) the rate of assisted delivery. Factors like inadequate LE, emergency situations and non-obstetric anesthesiologists can all be responsible for failed conversion of LE to surgical anesthesia for CS.

Labor epidural analgesia and the incidence of instrumental assisted delivery

OBJECTIVE

To assess the influence of labor epidural analgesia on the course of labor and to determine its association with instrumental assisted delivery rate.

MATERIALS AND METHODS

A retrospective case-control study was performed during 2007-2011 aiming to identify the relation between epidural analgesia (EA) and instrumental assisted delivery (IAD) rate. All patients in whom instrumental assistance for delivery was applied were allocated into either case (parturients who received EA and had IAD) or control (parturients who did not receive EA but had IAD) groups. Maternal demographic data, pregnancy and delivery characteristics as well as neonatal short-term outcome were studied.

RESULTS

A total of 7675 vaginal deliveries occurred during the study period and 187 (2.43%) patients had IAD. Vacuum extraction was applied to 67 (2.16%) parturients who received EA, and to 120 (2.61%) who did not. The median duration of the first stage of labor was 510 min in the EA group as compared to 390 min in the control group (P=0.001). The median duration of the second stage of labor among cases and controls was 60 and 40 min, respectively (P<0.0005). Cases more often had their labor induced by oxytocin 80.3% as compared to 58.3% among controls (P=0.003). There was no significant association between the use of EA and increased IAD rate (OR=0.81; 95% CI, 0.60-1.09).

CONCLUSIONS

Labor EA did not increase the incidence of IAD and the risk of adverse neonatal outcomes, but was associated with prolonged first and second stages of labor.

Impact of the introduction of neuraxial labor analgesia on mode of delivery at an urban maternity hospital in China

OBJECTIVE

To evaluate the association between the introduction of neuraxial (epidural) labor analgesia and mode of delivery in a large urban maternity hospital in China.

METHODS

A single-intervention impact study was conducted at Shijiazhuang Obstetrics and Gynecology Hospital in Shijiazhuang. Baseline data collection occurred between August 1 and December 31, 2009, when no analgesic method was routinely employed during labor. An intervention was then implemented, consisting of a neuraxial labor analgesia service. The service was fully operational from September 1, 2010, and data were collected to August 31, 2011. The mode of delivery was compared between the different periods.

RESULTS

Neuraxial analgesia rate was used in none of the 3787 deliveries during the baseline period and 3429 (33.5%) of 10 230 in the implementation period. Cesareans were performed in 1533 (40.5%) deliveries in the baseline period and 3441 (33.6%) in the implementation period (difference -6.8%, 99.8% confidence interval [CI] -9.7% to -3.9%; P<0.0017). The proportion of vaginal deliveries in which forceps were used was unchanged (difference -0.8%, 99.8% CI -0.7% to 2.2%; P=0.92).

CONCLUSION

The introduction of epidural analgesia reduced the frequency of cesarean delivery, which improved obstetric and neonatal outcomes.

Neuraxial analgesia: a review of its effects on the outcome and duration of labor

Labor pain is one of the most challenging experiences encountered by females during their lives. Neuraxial analgesia is the mainstay analgesic for intrapartum pain relief. However, despite the increasing use and undeniable advantages of neuraxial analgesia for labor, there have been concerns regarding undesirable effects on the progression of labor and outcomes. Recent evidence indicates that neuraxial analgesia does not increase the rate of Cesarean sections, although it may be associated with a prolonged second stage of labor and an increased rate of instrumental vaginal delivery. Even when neuraxial analgesia is administered early in the course of labor, it is not associated with an increased rate of Cesarean section or instrumental vaginal delivery, nor does it prolong the labor duration. These data may help physicians correct misconceptions regarding the adverse effects of neuraxial analgesia on labor outcome, as well as encourage the administration of neuraxial analgesia in response to requests for pain relief.

Controversies in obstetric anesthesia

Obstetric anesthesia has become a widely evidence-based practice, with an increasing number of specialized anesthesiologists and a permanent research production. We believe that with the review of commonly discussed and controversial points the reader will be able to incorporate an evidence-based practice into their routine and offer to parturients and their babies a safe, reliable and consistent anesthesia care.

The influence of analgesia on labor--is it related to primary cesarean rates?

Multiple observational studies have reported an association between neuraxial (epidural, spinal, or combined spinal-epidural) labor analgesia and cesarean delivery. The purpose of this review is to summarize data from controlled trials addressing the question of whether neuraxial labor analgesia causes an increased risk of cesarean delivery. Additionally, the review will discuss whether the timing of initiation of analgesia or the specific type of neuraxial analgesia influences mode of delivery. Finally, the issue of external validity of published trials will be discussed.

Effect of Availability of a Parturient-elective Regional Labor Pain Relief Service on the Mode of Delivery

BACKGROUND/PURPOSE

Regional analgesia for labor pain relief is effective and widely used. This study evaluated the controversial association between mode of operative delivery and patient-elective labor regional analgesia.

METHODS

We retrospectively compared the rates of instrumental vaginal and cesarean deliveries in parturients before the introduction, in the first 15 months after, and in the subsequent 36 months after the implementation of an elective labor regional analgesia service. A total of 9779 low-risk singleton cephalic pregnancies above 36 weeks of gestation were included. The maternal and fetal outcomes for parturients before the service was implemented and in those with or without pain relief service in the two postimplementation periods were analyzed. Multivariate logistic regression analyses were used to investigate the effects of maternal age, gestational weeks and newborn weight, in addition to regional analgesia, on the mode of delivery in nulliparous women.

RESULTS

After adjusting for maternal age, gestational weeks, and newborn weight, no significant association was found between regional analgesia and cesarean delivery in nulliparas. Further, this lack of association was not affected by the receipt of regional analgesia in the early period of program implementation or in the period after staff had become familiar with the service. A higher rate of instrumental vaginal delivery was noted in nulliparas given regional analgesia.

CONCLUSION

Regional analgesia for pain relief increased the likelihood of instrumental vaginal delivery, but did not increase the likelihood of cesarean delivery.

Epidural analgesia for childbirth: effects of newer techniques on neonatal outcome

New low-dose, local anesthetic-opioid combinations, combined spinal epidural analgesia, and new anesthetic drugs, such as ropivacaine and levobupivacaine, have modified the anesthetic practice in obstetric labor analgesia. These new analgesic techniques have less or no neonatal effects when compared with traditional epidural labor analgesia. They also have less effect on mode of delivery, which may in turn affect neonatal outcome. The use of very diluted or low concentrations of local anesthetic solutions may reduce their placental passage and thus the possible subtle neonatal effects. Small doses of epidural or spinal opioids alone or combined with low doses of local anesthetics does not affect the well-being of the neonate at birth. When considering the neonatal outcome, combined spinal epidural analgesia is as well tolerated as low-dose epidural analgesia. Transient fetal heart rate changes have been described immediately after the administration of intrathecal or epidural opioids. Maternal hypotension may also occur at the onset of epidural analgesia. Whether the occurrence of transient fetal heart rate changes or maternal hypotension immediately after the epidural block may influence the neonatal outcome at birth needs verification.

Prenatal risk factors for Caesarean section. Analyses of the ALSPAC cohort of 12,944 women in England

BACKGROUND

There has been an escalation in Caesarean section rates globally. Numerous prenatal factors have been associated with elective and emergency Caesarean section, some of which may be amenable to change.

METHODS

A population-based cohort of 12,944 singleton, liveborn, term pregnancies were used to investigate risk factors for Caesarean section using multivariable logistic regression modelling. Numerous prenatal factors were investigated for their associations with the following outcomes: first, with Caesarean section (both elective and emergency) compared with vaginal delivery (spontaneous and assisted); second, for their associations with elective Caesarean section compared with attempted vaginal delivery; and finally emergency Caesarean section compared with spontaneous vaginal delivery.

RESULTS

11,791 women had vaginal delivery and 1153 had Caesarean section (685 emergency, 468 elective). Non-cephalic (breech) presentation (all Caesareans odds ratio (OR) 36.6, 95% confidence interval (CI) 26.8-50.0; elective Caesarean OR 86.4, 95% CI 58.5-127.8; emergency Caesarean OR 9.58, 95% CI 6.06-15.1) and previous Caesarean section (all Caesareans OR 27.8, 95% CI 20.9-37.0, elective Caesarean OR 54.4, 95% CI 38.4-77.5; emergency Caesarean OR 13.0, 95% CI 7.76-21.7) were associated in all analyses with an increased risk of Caesarean section. Extremes of neonatal birthweight were associated with an increased risk of Caesarean section (all Caesareans and emergency section) compared with vaginal delivery as was increasing neonatal head circumferences. In all analyses increasing maternal age (OR 1.07 per year, 95 % CI 1.04-1.09; OR 1.04 per year, 95 % CI 1.01-1.08; OR 1.11 per year, 95% CI 1.08-1.15) was independently associated with increased odds of Caesarean section. Increasing parity was associated with a decrease in risk for all Caesareans and emergency section (OR 0.63, 95% CI 0.53-0.75 and OR 0.46, 95% CI 0.33-0.63, respectively), as was the outcome of the last pregnancy being a live child. Increasing gestation was independently associated with a decreased risk of both all Caesareans and elective Caesarean (OR 0.86, 95% CI 0.80-0.93 and OR 0.52, 95% CI 0.46-0.58 respectively), whereas diabetes mellitus was associated with increased risk. These variables were not associated with emergency section. However, epidural use was associated with an increased risk of emergency Caesarean (OR 6.49, 95% CI 4.78-8.82) while being in a preferred labour position decreased the risk (OR 0.59, 95% CI 0.49-0.73).

CONCLUSIONS

A careful exploration of risk factors may allow us to identify reasons for the increasing rates of Caesarean section and the marked variation between institutions.

Misconceptions about neuraxial analgesia

Neuraxial analgesia is the most effective treatment for labor pain. Although there are known risks and side effects, many problems are attributed to the technique without appropriate scientific assessment. Some observations, such as the increased use of forceps and prolonged second stage of labor, are associated with epidural analgesia, but there is not enough evidence to categorically state whether the technique caused the problems. These topics warrant continued investigation.

Epidural analgesia: effects on labor progress and maternal and neonatal outcome

The intended and unintended effects of epidural labor analgesia are reviewed. Mothers randomized to epidural rather than parenteral opioid analgesia have better pain relief. Fetal oxygenation is not affected by analgesic method; however, neonates whose mothers received intravenous or intramuscular opioids rather than epidural analgesia require more naloxone and have lower Apgar scores. Epidural analgesia does not affect the rates of cesarean delivery, obstetrically indicated instrumented vaginal delivery, neonatal sepsis, or new-onset back pain. Epidural analgesia is associated with longer second labor stages, more frequent oxytocin augmentation, and maternal fever (particularly among women who shiver and women receiving epidural analgesia for > 5 hours) but not with longer first labor stages. Epidural analgesia has no affect but intrapartum opioids decrease lactation success. Epidural use and urinary incontinence are weakly, but probably not causally, associated. Epidural labor analgesia would improve if the mechanisms of these unintended effects could be determined.

Economic considerations related to providing adequate pain relief for women in labour: comparison of epidural and intravenous analgesia

Epidural analgesia and intravenous analgesia with opioids are two techniques for providing pain relief for women in labour. Labour pain is comparable to surgical pain in its severity, and epidural analgesia provides better relief from this pain than intravenous analgesia; a meta-analysis quantified this improvement to be 40 mm on a 100mm pain scale during the first stage of labour. Epidural analgesia also has fewer adverse effects. However, providing epidural analgesia for labour pain costs more. The full cost of providing epidural analgesia can be divided into two components: a baseline-cost component, which captures the costs of hospital care to parturients receiving intravenous analgesia for labour pain; and an incremental-cost component, which estimates the costs arising from incremental care specific to epidural analgesia. The baseline component may be constructed using hospital cost-accounting data pertaining to actual obstetric patients. The incremental component is constructed from a set of recognised complications of epidural and intravenous analgesia, associated incidence rates and estimates of the costs involved, from society's perspective. The incremental expected cost per patient to society of providing epidural analgesia was calculated to be approximately $US338 (1998 values). This cost difference results primarily from increased professional costs (and is particularly sensitive to the method used to estimate the cost of anaesthesia professional services) and increased complication costs associated with epidural analgesia. A rational social policy for providing labour analgesia must weigh the value of improved pain relief from epidural analgesia against the increased cost of epidural analgesia.

Approaches to heterogeneity in meta-analysis

This paper reviews publications from January 1999 to March 2001 on reproductive health topics that were self-identified as meta-analysis or were indexed as meta-analysis in MEDLINE. It sought to assess whether tests of statistical heterogeneity were done, whether the results were reported, and how a finding of significance for a test of statistical heterogeneity was handled and the results interpreted. The review identified some concerns. Tests of statistical heterogeneity were not done universally even though virtually all writers on the topic emphasize their importance. Even when done, results of these tests were not universally reported. Although the consensus appears to be that heterogeneity tests are conservative for meta-analysis of studies and a probability value of 0.10 is preferred, many meta-analyses used the conventional value of 0.05 without providing a reason. The rationale for the choice of a random or fixed effects model was not generally evident. The review also provided some positive models and some recommendations for assessing, reporting and exploring heterogeneity are made considering these models and the published recommendations of experts.

Epidural and spinal analgesia and labour

Epidural and spinal analgesia for pain relief in labour are now commonplace. Adverse effects such as hypotension and toxicity to anaesthetic agents are well described and easily managed. The effects on obstetric outcome, however, have been unclear to both obstetricians and anaesthetists, but are important due to the large number of pregnancies involved. Efforts to define implications for mother and child have been frustrated by a relative lack of evidence derived from good quality, large randomized trials. Ethical and methodological difficulties together with an abundance of confounding factors have conspired to cause considerable difficulties for researchers in this area. Nevertheless, recent evidence has significantly advanced knowledge in the field and has implications for future practice.

Anesthesia and the progress of labour

CONCLUSIONS

The last decade has seen a remarkable advance in our understanding of the effects of regional analgesia on the progress and outcome of labour. In particular, the appearance of several well conducted prospective, randomized trials have helped confirm the opinion of most anesthesiologists and a growing number of obstetricians, that epidural analgesia only minimally lengthens labour and does not increase the risk of cesarean section. But the extraordinary methodological complexities of studying this unblindable treatment in patients who are anything but ambivalent about whether or not they receive it ensures the debate will continue. It is perhaps time to move away from outcome studies and on to investigations of the putative mechanisms of any effects epidural analgesia may have on the labour and delivery process. It is also vital to place greater emphasis on the interaction between obstetrical practice, analgesic technique, and the patient. There may be important differences between subsets of patients with regard to their risk of cesarean section and the effect epidural analgesia may have on this risk. This is almost certainly true for certain obstetrical practices. Only by an appreciation of the actual physiology of epidural analgesia in the context of obstetrical care and the labour process itself will one of the longest running debates in anesthesiology come to an end.