Association of epidural analgesia with cesarean delivery in nulliparas

Delayed versus early pushing during the second stage of labour in primigravidas under epidural anaesthesia with occipitoposterior malposition: a randomised controlled study

This randomised controlled trial aimed to compare the effect of early and delayed pushing during the second stage of labour in women with occipitoposterior (OP) malposition. It included 184 nulliparous women with OP position randomised to early pushing in which women were allowed to push within one hour after full cervical dilatation or delayed pushing in which women were asked not to push for maximum of three hours or start pushing when the vertex was visible. The primary outcome was successful vaginal delivery. The rate of spontaneous vaginal delivery was significantly higher in the early pushing group (80.4 vs. 60.9%, p=.004) while the rate of instrumental vaginal delivery (30.4 vs. 15.4%) and CS (8.7 vs. 4.3%) was significantly higher in the delayed pushing group. Women in the delayed pushing group showed a significantly longer duration of the second stage (129.4 ± 7.5 vs. 61.6 ± 15.3 minutes, p<.001) and shorter duration of pushing (219.8 ± 74.8 vs. 693.9 ± 145.2 seconds, p<.001) .The rate of 2nd and 3rd degree perineal lacerations (19.6 and 13% vs. 5.4 and 8.7% respectively, p=.013) and vaginal tears (41.3 vs. 8.7%, p<.001) was significantly higher in the early pushing group. We concluded that early pushing during the second stage of labour is associated with higher rates of spontaneous vaginal delivery and vaginal and perineal lacerations.Clinical trial registration NCT03121274.Impact StatementWhat is already known on this subject? Occipitoposterior malposition is common during delivery especially in primigravida and is associated with higher rates of instrumental delivery and caesarean section. It can be managed through early or delayed pushing.What the results of this study add? Early pushing is associated with higher rates of spontaneous vaginal delivery, perineal and vaginal tears, shorter duration of second stage of labour, shorter duration of pushing, lower rates of both instrumental vaginal delivery and caesarean section.What the implications are of these findings for clinical practice and/or further research? Early pushing during the second stage of labour is associated with higher rates of spontaneous vaginal delivery and vaginal and perineal lacerations in women with OP malposition and should be tried and not delaying the pushing.

New multivariate tests for assessing covariate balance in matched observational studies

We propose new tests for assessing whether covariates in a treatment group and matched control group are balanced in observational studies. The tests exhibit high power under a wide range of multivariate alternatives, some of which existing tests have little power for. The asymptotic permutation null distributions of the proposed tests are studied and the P-values calculated through the asymptotic results work well in simulation studies, facilitating the application of the test to large data sets. The tests are illustrated in a study of the effect of smoking on blood lead levels. The proposed tests are implemented in an R package BalanceCheck.

Delivery mode and maternal and neonatal outcomes of combined spinal-epidural analgesia compared with no analgesia in spontaneous labor: A single-center observational study in Japan

AIM

We aimed to assess the outcomes of combined spinal-epidural (CSE) analgesia compared with no analgesia in spontaneous labor.

METHODS

We performed a retrospective cohort study of deliveries between 2008 and 2014 comparing two groups based on the use of CSE analgesia in both nulliparous and multiparous women. Adjusted odds ratios (aOR) were calculated using logistic regression analysis.

RESULTS

Among 5247 (3334 nulliparous, 1913 multiparous) singleton deliveries, 3041 (2045, 996, respectively) patients received CSE analgesia and 2206 (1289, 917, respectively) had no analgesia. CSE analgesia was associated with increased risk of oxytocin augmentation (P < 0.01), prolonged duration of labor (P < 0.01), instrumental delivery (aOR, 3.35; 95% confidence interval (CI), 2.69-4.19 for nulliparous and aOR, 2.13; 95% CI, 1.32-3.53 for multiparous women), blood loss volume during vaginal delivery (P < 0.01), meconium-stained amniotic fluid (aOR, 1.23; 95% CI, 1.02-1.51 and aOR, 1.39; 95% CI, 1.01-1.93) and Apgar score less than 7 at 1 min (aOR, 1.85; 95% CI, 1.28-2.74 and aOR, 2.65; 95% CI, 1.35-5.61) in both nulliparous and multiparous women, respectively, and umbilical arterial blood gas pH less than 7.15 (aOR, 2.69; 95% CI, 1.35-5.75) and umbilical arterial blood gas pH less than 7.10 (aOR, 3.69; 95% CI, 1.11-16.69) in multiparous women. There was no significant difference in incidence of cesarean delivery or Apgar score less than 7 at 5 min.

CONCLUSION

We observed several increased risks in obstetric and neonatal outcomes among pregnant women who received CSE analgesia during labor. Preparations for these risks are needed when administering CSE analgesia during labor.

Ultrasonographic evaluation of the second stage of labor. Predictive parameters for a successful vaginal delivery with or without neuraxial analgesia: a pilot study

PURPOSE

The aim of the study was to evaluate the progression and rotation of the fetal head during the second stage of labor using translabial ultrasound and to compare ultrasonographic data obtained in nulliparous women both receiving and not receiving neuraxial analgesia.

METHODS

The 49 patients enrolled in the study were divided into two groups according to receiving or not receiving neuraxial analgesia. Every half hour from full dilation to delivery, the ultrasonographic translabial parameters of Angle of Progression, Head Symphysis Distance, and Midline Angle were obtained and recorded by a single operator. Then, these records were compared between the two groups of patients.

RESULTS

Patients that underwent neuraxial analgesia presented with increased duration of the second stage of labor, with mean values of Angle of Progression significantly higher and of Midline Angle significantly lower for each time interval studied compared to patients without analgesia. A borderline significant relationship was found between administration of neuraxial analgesia and Head Symphysis Distance.

CONCLUSIONS

In this study, we demonstrated that combined spinal-epidural analgesia influences the duration of the second stage of labor and the initial progression and rotation of the fetal head through the birth canal, but not the kind of delivery. A correlation between Angle of Progression values and success in the application of a vacuum has been reported by other authors and confirmed in our study.

Epidurals: Do They or Don't They Increase Cesareans?

The controversy over whether epidurals increase the risk of cesarean has raged since the 1970s. This article provides a history of of the early observational research designed to answer this question and an in-depth analysis of the most recent randomized control trials. Based on the research, the author concludes that we cannot assure women that epidurals do not increase the risk of cesarean.

Management of Foley catheter induction among nulliparous women: a retrospective study

Background

Induction of labour is associated with increased risk for caesarean delivery among nulliparous women. The aims of this study were to evaluate the risk factors for caesarean delivery and to investigate the risk of maternal and neonatal infections in nulliparous women undergoing induction of labour by Foley catheter.

Methods

This clinical retrospective study of 432 nulliparous women with singleton pregnancy and intact amniotic membranes at or beyond 37 gestational weeks scheduled for induction of labour by Foley catheter was conducted over the course of one year, between January 2012 and January 2013, in Helsinki University Hospital. The main outcome measures were caesarean section rate and maternal and neonatal infections. Univariate and multivariate logistic regressions were used to estimate relative risks by odds ratios with 95 % confidence intervals.

Results

The caesarean section rate was 39.1 % (n = 169). In multivariate regression analysis, the factors associated with caesarean section were the need for oxytocin for labour induction [OR 2.9 (95 % CI 1.8-4.5) p < 0.001] and early epidural analgesia [OR 9.9 (95 % CI 2.1-47.5), p = 0.004]. The maternal intrapartum infection rate was 6.3 %, and the clinical neonatal infection rate was 2.8 %. In multivariate analysis, gestational diabetes was associated with maternal intrapartum infection [OR 4.3 (95 % CI 1.7-11.0, p = 0.002] and early epidural analgesia with neonatal clinical sepsis [OR 10.5 (95 % CI 1.4-76), p = 0.02].

Conclusions

Oxytocin induction and early epidural analgesia were associated with caesarean delivery. Gestational diabetes and early epidural analgesia were associated with infectious morbidity. Since the first caesarean delivery has a major impact on subsequent pregnancies, optimising labour induction among nulliparous women is important.

The degree of labor pain at the time of epidural analgesia in nulliparous women influences the obstetric outcome

Background

The increased pain at the latent phase can be associated with dysfunctional labor as well as increases in cesarean delivery frequency. We aimed to research the effect of the degree of pain at the time of epidural analgesia on the entire labor process including the mode of delivery.

Methods

We performed epidural analgesia to 102 nulliparous women on patients' request. We divided the group into three based on NRS (numeric rating scale) at the moment of epidural analgesia; mild pain, NRS 1-4; moderate pain, NRS 5-7; severe pain, NRS 8-10. The primary outcome was the mode of delivery (normal labor or cesarean delivery).

Results

There were significant differences in the mode of delivery among groups. Patients with severe labor pain had a significantly higher cesarean delivery compared to patients with moderate labor pain (P = 0.006). The duration of the first and second stage of labor, fetal heart rate, use of oxytocin and premature rupture of membranes had no differences in the three groups.

Conclusions

Our research showed that the degree of pain at the time of epidural analgesia request might influence the rate of cesarean delivery. Further research would be necessary for clarifying the mechanism that the augmentation of pain affects the mode of delivery.

Adjustment for compliance behavior in trials of epidural analgesia in labor using instrumental variable meta-analysis

OBJECTIVES

Intention-to-treat (ITT) analysis of randomized controlled trials (RCTs) may cause bias when compliance is poor. Noncompliance describes failure to comply with allocation in the intervention arm, and contamination describes uptake of the intervention in the control arm. Instrumental variable (IV) analysis can be applied in addition to the primary ITT analysis to estimate the causal effect adjusted for noncompliance and contamination, assuming that noncompliers would have had the same treatment benefit as compliers. We aimed to compare ITT and IV meta-analysis of the association between epidural analgesia in labor and cesarean section.

STUDY DESIGN AND SETTING

The study was restricted to 27 trials in a Cochrane Systematic Review. The association between epidural analgesia in labor and cesarean section was calculated using ITT and IV analyses. Pooled risk ratios (RRs) were calculated using fixed-effects meta-analysis.

RESULTS

In 18 trials with compliance data, noncompliance was 23% and contamination was 27%. In 10 trials with outcome data stratified by compliance, the pooled RR for cesarean section following epidural analgesia was 1.37 [95% confidence interval (CI): 1.00, 1.89; P = 0.049] using IV compared with 1.19 (95% CI: 0.93, 1.51; P = 0.16) using ITT.

CONCLUSION

ITT meta-analysis underestimates the effect of receiving epidural analgesia in labor on cesarean section compared with IV meta-analysis.

Epidural analgesia and operative delivery: a ten-year population-based cohort study in The Netherlands

OBJECTIVE

To describe trends in the use of epidural analgesia (EA) and to evaluate the association of EA with operative deliveries.

STUDY DESIGN

In this population-based, retrospective cohort study, women with an intention to deliver vaginally of a term, cephalic, singleton between 2000 and 2009 (n=1378458) were included. Main outcome measures were labor EA rates, unplanned caesarean section (CS), and instrumental vaginal delivery (IVD) including deliveries by either vacuum or forceps. Data were obtained from the Perinatal Registry of The Netherlands and logistic regression analyses were used.

RESULTS

Among nulliparous, EA use almost tripled over the 10-year span (from 7.7% to 21.9%), while rates of CS and IVD did not change much (+2.8% and -3.3%, respectively). Among multiparous, EA use increased from 2.4% to 6.8%, while rates of CS and IVD changed slightly (+0.8% and -0.7%, respectively). Multivariable analysis showed a positive association of EA with CS, which weakened in ten years, from an adjusted OR of 2.35 (95% CI, 2.18 to 2.54) to 1.69 (95% CI, 1.60 to 1.79; p<0.001) in nulliparous, and from an adjusted OR of 3.17 (95% CI, 2.79 to 3.61) to 2.56 (95% CI, 2.34 to 2.81; p<0.001) in multiparous women. A weak inverse association between EA and IVD was found among nulliparous (adjusted OR, 0.76; 95% CI, 0.75 to 0.78), and a positive one among multiparous women (adjusted OR, 2.08; 95% CI, 2.00 to 2.16). Both associations grew slightly weaker over time.

CONCLUSIONS

A near triplication of EA use in The Netherlands in ten years was accompanied by relatively stable rates of operative deliveries. The association between EA and operative delivery became weaker. This supports the idea that EA is not an important causal factor of operative deliveries.

Early versus late initiation of epidural analgesia for labour

BACKGROUND

Pain during childbirth is arguably the most severe pain some women may experience in their lifetime. Epidural analgesia is an effective form of pain relief during labour. Many women have concerns regarding its safety. Furthermore, epidural services and anaesthetic support may not be available consistently across all centres. Observational data suggest that early initiation of epidural may be associated with an increased risk of caesarean section, but the same findings were not seen in recent randomised controlled trials. More recent guidelines suggest that in the absence of a medical contraindication, maternal request is a sufficient medical indication for pain relief during labour. The choice of analgesic technique, agent, and dosage is based on many factors, including patient preference, medical status, and contraindications. There is no systematically reviewed evidence on the maternal and foetal outcomes and safety of this practice.

OBJECTIVES

This systematic review aimed to summarise the effectiveness and safety of early initiation versus late initiation of epidural analgesia in women. We considered the obstetric and fetal outcomes relevant to women and side effects of the treatments, including risk of caesarean section, instrumental birth and time to birth.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (12 February 2014), the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2014, Issue 1), MEDLINE (January 1966 to February 2014), Embase (January 1980 to February 2014) and reference lists of retrieved studies.

SELECTION CRITERIA

We included all randomised controlled trials involving women undergoing epidural labour analgesia that compared early initiation versus late initiation of epidural labour analgesia.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trials for inclusion, extracted the data and assessed the trial quality. Data were checked for accuracy.

MAIN RESULTS

We included nine studies with a total of 15,752 women.The overall risk of bias of the studies was low, with the exception of performance bias (blinding of participants and personnel).The nine studies showed no clinically meaningful difference in risk of caesarean section with early initiation versus late initiation of epidural analgesia for labour (risk ratio (RR) 1.02; 95% confidence interval (CI) 0.96 to 1.08, nine studies, 15,499 women, high quality evidence). There was no clinically meaningful difference in risk of instrumental birth with early initiation versus late initiation of epidural analgesia for labour (RR 0.93; 95% CI 0.86 to 1.01, eight studies, 15,379 women, high quality evidence). The duration of second stage of labour showed no clinically meaningful difference between early initiation and late initiation of epidural analgesia (mean difference (MD) -3.22 minutes; 95% CI -6.71 to 0.27, eight studies, 14,982 women, high quality evidence). There was significant heterogeneity in the duration of first stage of labour and the data were not pooled.There was no clinically meaningful difference in Apgar scores less than seven at one minute (RR 0.96; 95% CI 0.84 to 1.10, seven studies, 14,924 women, high quality evidence). There was no clinically meaningful difference in Apgar scores less than seven at five minutes (RR 0.96; 95% CI 0.69 to 1.33, seven studies, 14,924 women, high quality evidence). There was no clinically meaningful difference in umbilical arterial pH between early initiation and late initiation (MD 0.01; 95% CI -0.01 to 0.03, four studies, 14,004 women, high quality evidence). There was no clinically meaningful difference in umbilical venous pH favouring early initiation (MD 0.01; 95% CI -0.00 to 0.02, four studies, 14,004 women, moderate quality evidence).

AUTHORS' CONCLUSIONS

There is predominantly high-quality evidence that early or late initiation of epidural analgesia for labour have similar effects on all measured outcomes. However, various forms of alternative pain relief were given to women who were allocated to delayed epidurals to cover that period of delay, so that is it hard to assess the outcomes clearly. We conclude that for first time mothers in labour who request epidurals for pain relief, it would appear that the time to initiate epidural analgesia is dependent upon women's requests.

Epidural analgesia in labour and risk of caesarean delivery

BACKGROUND

A Cochrane Systematic Review of randomised controlled trials of epidural analgesia compared with other or no analgesia in labour reported no overall increased risk of caesarean delivery. However, many trials were affected by substantial non-compliance, and there are concerns about the external validity of some trials for contemporary maternity populations. We aimed to explore the association between epidural analgesia in labour and caesarean delivery in clinical practice and compare with findings from randomised controlled trials.

METHODS

Population-based cohort of pregnant women (n = 210 708) without major obstetrical complications who delivered a singleton live infant in hospitals in New South Wales, Australia, 2007-10. Data were obtained from linked, validated population-based data collections. Propensity score matching was used to examine the association between epidural analgesia in labour and caesarean delivery.

RESULTS

Epidural analgesia in labour was used by a third (31.5%, n = 66 317) of the women, and 9.8% (n = 20 531) had a caesarean delivery. Epidural analgesia in labour was associated with increased risk of caesarean delivery {risk ratio [RR] 2.5, [95% confidence interval (CI) 2.5, 2.6]}. The association with epidural analgesia in labour was higher for caesarean delivery for failure to progress {RR 3.0, [95% CI 2.9, 3.0]} than for caesarean delivery for fetal distress {RR 1.9, [95% CI 1.8, 2.0]}.

CONCLUSIONS

Epidural analgesia in labour is associated with caesarean delivery in a large maternity population. Population-based studies contribute important data about obstetrical care, when research settings and participants may not represent the clinical settings or broader population in which obstetrical interventions in labour are applied.

Update on best available options in obstetrics anaesthesia: perinatal outcomes, side effects and maternal satisfaction. Fifteen years systematic literature review

PURPOSE

In modern obstetrics, different pharmacological and non-pharmacological options allow to obtain pain relief during labour, one of the most important goals in women satisfaction about medical care. The aim of this review is to compare all the analgesia administration schemes in terms of effectiveness in pain relief, length of labour, mode of delivery, side effects and neonatal outcomes.

METHODS

A systematic literature search was conducted in electronic databases in the interval time between January 1999 and March 2013. Key search terms included: “labour analgesia”, “epidural anaesthesia during labour” (excluding anaesthesia for Caesarean section), “epidural analgesia and labour outcome” and “intra-thecal analgesia”.

RESULTS

10,331 patients were analysed: 5,578 patients underwent Epidural-Analgesia, 259 patients spinal analgesia, 2,724 combined spinal epidural analgesia, 322 continuous epidural infusion (CEI), 168 intermittent epidural bolus, 684 patient-controlled infusion epidural analgesia and 152 intra-venous patient-controlled epidural analgesia. We also considered 341 women who underwent patient-controlled infusion epidural analgesia in association with CEI and 103 patients who underwent patient-controlled infusion epidural analgesia in association with automatic mandatory bolus.

CONCLUSION

No significant differences occurred among all the available administration schemes of neuraxial analgesia. In absence of obstetrical contraindication, neuraxial analgesia has to be considered as the gold standard in obtaining maternal pain relief during labour. The options available in the administration of analgesia should be known and evaluated together by both gynaecologists and anaesthesiologists to choose the best personalized scheme and obtain the best women satisfaction. Since it is difficult to identify comparable circumstances during labour, it is complicate to standardize drugs schemes and their combinations.

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.

Women's perception of the onset of labour and epidural analgesia: a prospective study

OBJECTIVE

childbearing women and their midwives differ in their diagnoses of the onset of labour. The symptoms women use to describe the onset of labour are associated with the process of labour. Perinatal factors and women's attitudes may be associated with the administration of epidural analgesia. Our study aimed to assess the correlation between women's perception of the onset of labour and the frequency and timing of epidural analgesia during labour.

DESIGN

prospective cohort study.

SETTING

41 maternity units in Lower Saxony, Germany.

PARTICIPANTS

549 nulliparae (as defined in the "Methods" section) and 490 multiparae giving birth between April and October 2005. Women were included after 34 completed weeks of gestation with a singleton in vertex presentation and planned vaginal birth.

MEASUREMENTS

the association between women's symptoms at the onset of labour and the administration of epidural analgesia - frequency, timing in relation to onset of labour and cervical dilatation - was assessed. The analysis was performed by Kaplan-Meiers estimation, logistic regression and Cox regression.

FINDINGS

a total of 174 nulliparae and 49 multiparae received epidural analgesia during labour. Nulliparae received it at a median time of 5.47hrs (range: 0.25-51.17hrs) after onset of labour, at a median cervical dilatation of 3.3cm (range: 1.0-10.0cm). In multiparae, epidural analgesia was applied at a median time of 3.79hrs (range: 0.42-28.55hrs) after onset of labour; the median cervical dilatation was 3.0cm (range: 1.0-8.0cm). Women who were admitted with advanced cervical dilatation received epidural analgesia less often. Women who defined their onset of labour earlier than it was diagnosed by their midwives received epidural analgesia earlier. Gastrointestinal symptoms and irregular pain at the onset of labour were associated with later administration of epidural analgesia. Induction of labour was associated with a reduced interval from the onset of labour to epidural analgesia.

KEY CONCLUSIONS

women's self-diagnosis of the onset of labour and their perception of their labour duration when meeting their midwives has some impact on their admission to the labour ward and the timing of epidural analgesia.

IMPLICATIONS FOR PRACTICE

consideration of women's own perceptions and expectations regarding the onset and process of labour is necessary for individual care during labour.

Mode of delivery after epidural analgesia in a cohort of low-risk nulliparas

BACKGROUND

  Although epidural analgesia is widespread and very effective for alleviating labor pain, its use is still controversial, as the literature is inconsistent about the risk of adverse birth outcome after administration of epidural analgesia. The aim of this study was to explore associations between epidural analgesia and mode of delivery.

METHODS

  Data were obtained from a prospective cohort from nine Danish labor wards and comprised 2,721 term nulliparous women with spontaneous onset of labor and a singleton fetus in cephalic presentation. Information about epidural analgesia, mode of delivery, and birth complications was obtained by the staff attending labor. Additional information was provided from self-administered questionnaires in gestational week 37. Multiple logistic regression analyses were used to estimate the association between epidural analgesia and birth outcomes. Results are presented as crude and adjusted odds ratios (OR [95% CI]).

RESULTS

  Of the total cohort, 21.6 percent required epidural analgesia, 8.7 percent had emergency cesarean section, and 14.9 percent had vacuum extraction. Women with epidural analgesia had a higher risk of emergency cesarean section (adjusted OR: 5.8; 95% CI: 4.1-8.1), and vacuum extraction (adjusted OR: 1.7; 95% CI: 1.3-2.2). In a subgroup of the cohort with a very low overall risk of cesarean section, 3.4 percent had emergency cesarean section and an increased risk of emergency cesarean section was also found in this group (adjusted OR: 3.5; 95% CI: 1.5-8.2).

CONCLUSIONS

  In nulliparous women of a very low-risk population, use of epidural analgesia for labor pain was associated with higher risks of emergency cesarean section and vacuum extraction.

Higher caesarean section rates in women with higher body mass index: are we managing labour differently?

BACKGROUND

Higher body mass index has been associated with an increased risk of Caesarean section. The effect of differences in labour management on this association has not yet been evaluated.

METHODS

We conducted a cohort study using data from the McGill Obstetrics and Neonatal Database for deliveries taking place during a 10-year period. Women's BMI at delivery was categorized as normal (20 to 24.9), overweight (25 to 29.9), obese (30 to 39.9), or morbidly obese (≥ 40). We evaluated the effect of the management of labour on the need for Caesarean section using unconditional logistic regression models.

RESULTS

Data were available for 11 922 women, of whom 2289 women had normal weight, 5663 were overweight, 3730 were obese, and 240 were morbidly obese. After adjustment for known confounding variables, increased BMI category was associated with an overall increase in the use of oxytocin and in the use of epidural analgesia, and with a decrease in use of forceps and vacuum extraction among second stage deliveries. Higher BMI was also found to be associated with earlier decisions to perform a Caesarean section in the second stage of labour. When adjusted for these differences in the management of labour, the increasing rate of Caesarean section observed with increasing BMI category was markedly attenuated (P < 0.001).

CONCLUSION

Women with an increased BMI are managed differently in labour than women of normal weight. This difference in management in part explains the increased rate of Caesarean section observed with higher BMI.

Acupuncture for pain relief during induced labour in nulliparae: a randomised controlled study

OBJECTIVE

To assess the role of acupuncture for analgesia during labour.

DESIGN

Double-blind study of manual, electro and sham acupuncture, and single-blind study comparing acupuncture with a control group for analgesia for labour induction.

SETTING

A major obstetric unit in the UK.

POPULATION

A cohort of 105 nulliparae undergoing labour induction at term.

METHODS

Twenty-three subjects needed to be randomised to each group to have an 80% power of detecting a 50% relative reduction in epidural rate with an alpha value of 0.05.

MAIN OUTCOME MEASURES

The primary end point was the rate of intrapartum epidural analgesia, and the secondary end points were parenteral analgesia requirement, labour length, delivery mode, neonatal condition and postpartum haemorrhage.

RESULTS

There was no difference in epidural analgesia between acupuncture and sham acupuncture, relative risk 1.18 (95% CI 0.8-1.74), or between acupuncture and control, relative risk 0.88 (95% CI 0.66-1.19). There were no significant differences in the secondary end points between the acupuncture groups and the control group. Side effects or complications of acupuncture were not identified.

CONCLUSIONS

Using the protocols studied, there was no analgesic benefit with acupuncture for pain relief during induced labour in nulliparae.

[Epidural analgesia in obstetrics: is there an effect on labor and delivery?]

BACKGROUND AND OBJECTIVE

Epidural analgesia is routinely used in obstetrics but has been blamed for possible effects on labor that lead to greater use of instruments or conversion to cesarean delivery. We aimed to assess this possibility in a cohort of obstetric patients receiving or not receiving epidural analgesia.

PATIENTS AND METHODS

Prospectively enrolled full-term obstetric patients were distributed in 2 groups according to whether they received epidural analgesia or not. We compared maternal and fetal characteristics, obstetric variables, and type of delivery between groups to record the likely causes of difficult labor and delivery and detect a possible influence of epidural analgesia.

RESULTS

Of a total of 602 patients, 462 received epidural analgesia and 140 did not. Epidural analgesia was related to a higher rate of use of instruments but not cesareans (P < .01) and more frequent need for oxytocin (30.7% of the epidural analgesia group vs 0% of the group receiving no epidural analgesia, P < .001). The women receiving analgesia also had a longer mean (SD) duration of the dilatation phase of labor (6.4 [4.2] hours in the epidural group vs 4.7 [3.5] hours in the no-epidural group, P < .01) and of the expulsion phase (1.0 [0.6] hours vs 0.7 [0.6] hours, respectively; P<.01). We observed no effects on the incidence of tearing, rate of episiotomy, or other variables. Predictors of instrumentation or conversion to cesarean delivery were longer duration of the first phase (odds ratio [OR] 1.2; 95% confidence interval [CI], 1.1-1.3), longer duration of the second phase (OR 2.3; 95% CI, 1.3-3.9), and maternal obesity (OR, 1.1; 95% CI, 0.9-1.2). Previous deliveries and initiation of epidural analgesia after the fetus has reached Hodge's first plane decreased risk 2.7-fold and 3.03-fold, respectively.

CONCLUSIONS

Although epidural analgesia has traditionally been associated with a higher incidence of difficult labor and delivery, this association was not unequivocally evident in this cohort of patients. The apparent increase seems to be attributable to such obstetric factors as longer duration of stages of labor, higher body mass index, and first delivery.

A traffic safety evaluation of California's traffic violator school citation dismissal policy

INTRODUCTION

This study evaluated California's traffic violator school (TVS) citation dismissal policy.

METHOD

This study identified and compared two large samples of drivers either completing a TVS (N=210,015) or convicted of a traffic citation (N=168,563).

RESULTS

Prior to adjudication, the TVS group had characteristics (e.g., lower prior conviction rate and smaller proportion of males) that were predictive of a lower subsequent crash risk. However, the TVS group exhibited significantly more crashes than did the convicted group in the subsequent one-year period. The difference (4.83%) increased to 10% after adjusting for the more favorable characteristics of the TVS group. The TVS group also had a higher adjusted subsequent crash rate at each prior driver record entry level, reflecting a loss in the general and specific deterrence of the non-conviction masked status of TVS dismissed citations. It was reported that the TVS dismissal policy results in approximately 12,300 additional crashes annually with economic costs of approximately $398,000,000.

CONCLUSIONS

The avoidance of licensing actions resulting from the dismissal policy assists in explaining why the driving public is exposed to an increased crash risk. A number of recommendations are offered to reduce the negative traffic safety impact of the TVS citation dismissal policy.

Epidural analgesia for low risk labour determines the rate of instrumental deliveries but not that of caesarean sections

We analysed retrospectively the link between the incidence of epidural analgesia and the frequency distribution of instrumental delivery, caesarean section, labour induction and parity in a selected group of women with a low risk labour profile in all (85) obstetric units in Flanders (Northern Belgium). A group of 104 932 women with presumed low risk labour profile was subjected to analysis. The main outcome measures were the incidence of obstetric intervention in each obstetric unit in relation to the extent of their use of epidural analgesia. There was a wide variation in the rate of epidural analgesia (3-75%), labour induction 'for convenience' (4-48%) and instrumental delivery (4-50%) among the Flemish obstetric units. The incidence of instrumental delivery in a given unit was greatly influenced by the rate of epidural analgesia and labour induction for convenience (P < 0.001). However, the incidence of caesarean section in a given unit was not determined by either the rates of epidural, labour induction, attempted instrumental delivery or the size of the unit.

Disparities in cesarean delivery rates and associated adverse neonatal outcomes in New York City hospitals

OBJECTIVE

To examine the primary cesarean delivery rates and associated neonatal outcomes by insurance status in public and private hospitals in New York City.

METHODS

We accessed Vital statistics data on all births to women with Medicaid or private insurance from 1996 through 2003, compiling a total of 321,308 nulliparous women who delivered singleton neonates by either normal spontaneous vaginal delivery or primary cesarean delivery. Rates of primary cesarean delivery and adverse neonatal outcomes were examined by hospital type and insurance status while controlling for potential confounders.

RESULTS

There were 51,682 and 269,626 women who delivered in public hospitals and private hospitals, respectively. The cesarean delivery rate of women with private insurance delivering in private hospitals was 30.4% compared with a cesarean rate of 21.2% in Medicaid patients delivering in public hospitals (adjusted odds ratio [OR] 1.57, 95% confidence interval [CI] 1.53-1.63). The percent of infants born to women with private insurance and Medicaid delivering in private hospitals with a 5-minute Apgar score less than 7 was 0.6% and 0.8% compared with 1.0% of infants delivering in the public hospital system (adjusted OR 0.59, 95% CI 0.51- 0.68 and adjusted OR 0.73, 95% CI 0.65- 0.82). The neonatal intensive care unit admission rate was also lower in neonates born in private hospitals at 6.7% and 8.5% compared with a 12.8% admission rate in public hospitals (adjusted OR 0.48, 95% CI 0.46-0.51 and adjusted OR 0.59, 95% CI 0.57- 0.62 after controlling for mode of delivery).

CONCLUSION

Even when controlling for confounders, there was an association between primary cesarean delivery and insurance status regardless of hospital type. There was also a higher risk of adverse neonatal outcomes in the public hospitals regardless of mode of delivery.

LEVEL OF EVIDENCE

III.

Impact of pain level on second-stage delivery outcomes among women with epidural analgesia: results from the PEOPLE study

OBJECTIVE

The objective of the study was to assess the effect of suboptimal second-stage pain control on the risk of difficult delivery.

STUDY DESIGN

We conducted a secondary analysis of the Pushing Early Or Pushing Late with Epidural (PEOPLE) randomized, controlled trial cohort on second-stage nulliparous women. We defined suboptimal pain control as a visual analog pain scale score of 30 or greater on a scale of 100 and evaluated initial postrandomization and subsequent pain control on obstetrical interventions and outcomes. We estimated adjusted relative risk for caesarean delivery using logistic regression models to control for confounding variables and to evaluate the role of effect measure modifiers.

RESULTS

One thousand seven hundred fifty-six women were included in the cohort, of which 1565 (89.1%) had optimal analgesia and 191 (10.9%) had suboptimal analgesia. Women with suboptimal analgesia had an increased risk of cesarean delivery of 2.97 (1.52-5.80), midpelvic procedures of 1.83 (1.10-3.05), and third- and fourth-degree perineal tears of 1.82 (1.03-3.21). As compared with women with sustained optimal analgesia, increasing levels of pain were associated with an increase in difficult deliveries, 2.19 (1.50-3.21). The improvement of relief among women with initial suboptimal initial analgesia did not alter the risk of difficult deliveries.

CONCLUSION

Although most women achieve optimal epidural analgesia, the inability to sustain optimal epidural analgesia is associated with an increased risk of adverse second-stage obstetrical outcomes.

Walking Epidural : An Effective Method of Labour Pain Relief

BACKGROUND

Labour pain can be deleterious for mother and baby. Epidural analgesia relieves labour pains effectively with minimal maternal and foetal side effects. A prospective open label study was undertaken to ascertain effective dosing regime for walking epidural in labour.

METHODS

Fifty women with singleton foetus in vertex position were included. Epidural catheter was inserted in L2-3 / L3-4 interspinous space. Initial bolus of 10 ml (0.1% bupivacaine and 0.0002% fentanyl) solution was injected and after the efficacy of block was established, an epidural infusion of the same drug solution was started at the rate of 5 ml/hour.

RESULTS

In first stage of labour 80% of the parturient had excellent to good pain relief (visual analogue scale 1 to 3) with standard protocol while 20% parturient required one or more additional boluses. For the second stage, pain relief was good to fair (VAS 4-6) for most of the parturient. The incidence of caesarian section was 4% and 6% needed assisted delivery. No major side effects were observed.

CONCLUSION

0.1% bupivacaine with 0.0002% fentanyl maximizes labour pain relief and minimizes side effects.

Effects of epidural lidocaine analgesia on labor and delivery: a randomized, prospective, controlled trial

Background

Whether epidural analgesia for labor prolongs the active-first and second labor stages and increases the risk of vacuum-assisted delivery is a controversial topic. Our study was conducted to answer the question: does lumbar epidural analgesia with lidocaine affect the progress of labor in our obstetric population?

Method

395 healthy, nulliparous women, at term, presented in spontaneous labor with a singleton vertex presentation. These patients were randomized to receive analgesia either, epidural with bolus doses of 1% lidocaine or intravenous, with meperidine 25 to 50 mg when their cervix was dilated to 4 centimeters. The duration of the active-first and second stages of labor and the neonatal apgar scores were recorded, in each patient. The total number of vacuum-assisted and cesarean deliveries were also measured.

Results

197 women were randomized to the epidural group. 198 women were randomized to the single-dose intravenous meperidine group. There was no statistical difference in rates of vacuum-assisted delivery rate. Cesarean deliveries, as a consequence of fetal bradycardia or dystocia, did not differ significantly between the groups. Differences in the duration of the active-first and the second stages of labor were not statistically significant. The number of newborns with 1-min and 5-min Apgar scores less than 7, did not differ significantly between both analgesia groups.

Conclusion

Epidural analgesia with 1% lidocaine does not prolong the active-first and second stages of labor and does not increase vacuum-assisted or cesarean delivery rate.

Epidural anaesthesia for labour: does it influence the mode of delivery?

BACKGROUND

Epidural anaesthesia (EDA) is an effective method to lower labour pain. EDA might have an impact on instrumental delivery rates and on caesarean section rates. The present study compares the mode of delivery in women who were either receiving EDA or not. The indication for EDA was pain relief only in order to switch off a selection bias.

METHODS

During a 1-year duration, we included a total of 1,452 cases. Exclusion criteria were factors that could influence the mode of delivery, independent from EDA, as well as obstetrical indications for administering EDA. 530 women remained in the analysis. The primary outcome variable was the mode of delivery.

RESULTS

We detected in both nullipara and multipara a statistically significant accumulatin in patients with EDA and caesarean section combined. Most importantly, the majority of the women without EDA (57% of nullipara and 60% of multipara) delivered within the median timeframe from admission until administration of EDA.

CONCLUSIONS

It seems to be obvious to conclude that EDA as performed in our study results in a higher rate of caesarean sections. It is important though to take into consideration that between the period from admission to the delivery ward and administration of EDA most of the parturients without EDA had already delivered. Our results make evident, that the administration of EDA exclusively used for reducing labour pain is a result of a complex collaboration of temporal conditions of labour as well as psychological conditions and also of the mother's wish.

Prenatal maternal stress is associated with delivery analgesia and unplanned cesareans

We tested the hypothesis that women with greater prenatal maternal stress (PNMS) would be more likely to receive intravenous opiates and epidural for delivery, and thereby increase the likelihood of unplanned cesarean delivery. PNMS was assessed during early, mid, and late pregnancy using psychometrically sound instruments in structured interviews with women receiving prenatal care at a public university clinic. Medical records were abstracted for analgesia during delivery, fetal heart tracing (FHT) abnormalities, and method of delivery. Only subjects attempting vaginal delivery (N = 298) were included. Using structural equation modeling, a PNMS variable was constructed from five indicators: pregnancy-specific distress, number of prenatal stressful life events, distress from life events, state anxiety, and perceived stress. After controlling for medical predictors of analgesia receipt and surgical delivery, women with higher PNMS were more likely to receive analgesia, and those who received analgesia were more likely to deliver surgically. Analgesia was also associated with FHT abnormalities, which in turn was associated with surgical delivery (all p's < 0.05). Women who received both an epidural and meperidine were most likely to have a cesarean delivery; 29% of this group delivered surgically. Results indicate that PNMS contributes to higher likelihood of unplanned cesarean delivery through its association with delivery analgesia.

[Evaluation of controlled-release dinoprostone Propess for labor induction]

OBJECTIVE

To evaluate the efficacy of cervix ripening with vaginal controlled-release Propess.

PATIENTS AND METHODS

A retrospective study of all women who underwent cervical ripening with Propess during the study period from 1(st) January 2002 to 31(st) December 2004 was carried out. A total of 130 patients who experienced Propess was compared with the next following patient who delivered spontaneously matched on gestational age. Modes of delivery, failure of labor, maternal morbidity were recorded.

RESULTS

Indications for induction of labor were: post-term pregnancies in 18.5%, pre-eclampsia in 20.8%, oligohydroamnios in 18.5%, post-term pregnancy and oligohydramnios in 10.8%, intra-uterine fetal growth in 6.9%, premature rupture of membranes in 6.9%, diminution of fetal mobility in 6.1% and miscellaneous in 11.5%. Failure of cervical ripening was 21.2%. Patients in the Propess group had a 3.5 fold higher risk of Cesarean section [95% CI: 1.5-8.3; P < 0.04]. There was no case of maternal or fetal death. There was no difference in incidence of maternal complications, and post-partum haemorrhage.

DISCUSSION AND CONCLUSION

Use of vaginal pessary Propess does not induce adverse maternal or fetal morbidity. However, it was associated with a higher incidence of Cesarean delivery.

A review of the application of propensity score methods yielded increasing use, advantages in specific settings, but not substantially different estimates compared with conventional multivariable methods

OBJECTIVE

Propensity score (PS) analyses attempt to control for confounding in nonexperimental studies by adjusting for the likelihood that a given patient is exposed. Such analyses have been proposed to address confounding by indication, but there is little empirical evidence that they achieve better control than conventional multivariate outcome modeling.

STUDY DESIGN AND METHODS

Using PubMed and Science Citation Index, we assessed the use of propensity scores over time and critically evaluated studies published through 2003.

RESULTS

Use of propensity scores increased from a total of 8 reports before 1998 to 71 in 2003. Most of the 177 published studies abstracted assessed medications (N=60) or surgical interventions (N=51), mainly in cardiology and cardiac surgery (N=90). Whether PS methods or conventional outcome models were used to control for confounding had little effect on results in those studies in which such comparison was possible. Only 9 of 69 studies (13%) had an effect estimate that differed by more than 20% from that obtained with a conventional outcome model in all PS analyses presented.

CONCLUSIONS

Publication of results based on propensity score methods has increased dramatically, but there is little evidence that these methods yield substantially different estimates compared with conventional multivariable methods.

Early versus late initiation of epidural analgesia in labor: does it increase the risk of cesarean section? A randomized trial

OBJECTIVE

To determine whether early initiation of epidural analgesia in nulliparous women affects the rate of cesarean sections and other obstetric outcome measures.

STUDY DESIGN

A randomized trial in which 449 at term nulliparous women in early labor, at less than 3 cm of cervical dilatation, were assigned to either immediate initiation of epidural analgesia at first request (221 women), or delay of epidural until the cervix dilated to at least 4 cm (228 women).

RESULTS

At initiation of the epidural the mean cervical dilatation was 2.4 cm in the early epidural group and 4.6 cm in the late group (P < 0.0001). The rates of cesarean section were not significantly different between the groups--13% and 11% in the early and late groups, respectively (P = 0.77). The mean duration from randomization to full dilatation was significantly shorter in the early compared to the late epidural group--5.9 hours and 6.6 hours respectively (P = 0.04). When questioned after delivery regarding their next labor, the women indicated a preference for early epidural.

CONCLUSION

Initiation of epidural analgesia in early labor, following the first request for epidural, did not result in increased cesarean deliveries, instrumental vaginal deliveries, and other adverse effects; furthermore, it was associated with shorter duration of the first stage of labor and was clearly preferred by the women.

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.

Bishop Score and Risk of Cesarean Delivery After Induction of Labor in Nulliparous Women

OBJECTIVE

To quantify the risk and risk factors for cesarean delivery associated with medical and elective induction of labor in nulliparous women.

METHODS

A prospective cohort study was performed in nulliparous women at term with vertex singleton gestations who had labor induced at 2 obstetrical centers. Medical and elective indications and Bishop scores were recorded before labor induction. Obstetric and neonatal data were analyzed and compared with the results in women with a spontaneous onset of labor. Data were analyzed using univariate and multivariable regression modeling.

RESULTS

A total of 1,389 women were included in the study. The cesarean delivery rate was 12.0% in women with a spontaneous onset of labor (n = 765), 23.4% in women undergoing labor induction for medical reasons (n = 435) (unadjusted odds ratio [OR] 2.24; 95% confidence interval [CI] 1.64-3.06), and 23.8% in women whose labor was electively induced (n = 189) (unadjusted OR 2.29; 95% CI 1.53-3.41). However, after adjusting for the Bishop score at admission, no significant differences in cesarean delivery rates were found among the 3 groups. A Bishop score of 5 or less was a predominant risk factor for a cesarean delivery in all 3 groups (adjusted OR 2.32; 95% CI 1.66-3.25). Other variables with significantly increased risk for cesarean delivery included maternal age of 30 years or older, body mass index of 31 or higher, use of epidural analgesia during the first stage of labor, and birth weight of 3,500 g or higher. In both induction groups, more newborns required neonatal care, more mothers needed a blood transfusion, and the maternal hospital stay was longer.

CONCLUSION

Compared with spontaneous onset of labor, medical and elective induction of labor in nulliparous women at term with a single fetus in cephalic presentation is associated with an increased risk of cesarean delivery, predominantly related to an unfavorable Bishop score at admission.

LEVEL OF EVIDENCE

II-2.

Propensity score estimation with boosted regression for evaluating causal effects in observational studies

Causal effect modeling with naturalistic rather than experimental data is challenging. In observational studies participants in different treatment conditions may also differ on pretreatment characteristics that influence outcomes. Propensity score methods can theoretically eliminate these confounds for all observed covariates, but accurate estimation of propensity scores is impeded by large numbers of covariates, uncertain functional forms for their associations with treatment selection, and other problems. This article demonstrates that boosting, a modern statistical technique, can overcome many of these obstacles. The authors illustrate this approach with a study of adolescent probationers in substance abuse treatment programs. Propensity score weights estimated using boosting eliminate most pretreatment group differences and substantially alter the apparent relative effects of adolescent substance abuse treatment.

Prise en charge du travail et de l’accouchement chez la nullipare à bas risque : comparaison d’une maternité de type 1 et d’une maternité de type 3

OBJECTIVES

To compare obstetrical practices between level 1 ( community hospital) and level 3 (university hospital) maternities in a low risk nulliparous population.

MATERIALS AND METHODS

1532 low risk nulliparas were included in a retrospective study conducted in the setting of two maternities in the Ile-de-France area. Cesarean delivery and forceps rates, management of labor, analgesia, maternal and neonatal outcomes were compared.

RESULTS

Cesarean delivery rates were not significantly different (11.5% in level 3 vs 10.2% in level 1). Level 1 maternity performed induction of labor more often (14.7% vs 8.7%, p<0.01). Peridural analgesia rates were higher in the level 3 maternity (95.1% vs 75.5%. p<0.01) but general anesthesia was two-fold more frequent in level 1 maternity. Level 3 maternity performed more instrumental deliveries (27.5% vs 17.4%, p<0.01) and more episiotomies (72.7% vs 39.3%). But we noted more first and second degree perineal tears in the level 1 maternity (29.9% vs 17.4%, p<0.01). Neonatal hospitalizations were more frequently in level 3 maternity.

CONCLUSION

Some "interventionist" practices, but not all, were less frequent amongst physicians managing mainly low-risk women than amongst physicians managing mainly high-risk women but without difference for the cesarean delivery rates. The main differences were observed for epidural, instrumental delivery, and episiotomy rates but perineal tears and induction of labor were more frequent in the level I maternity. These differences could be explained by obstetrical politics in the two maternities rather than the type of level.

Physician contribution to a cesarean delivery risk model

OBJECTIVE

The purpose of this study was to assess the contribution of physician management to the probability of cesarean delivery.

STUDY DESIGN

A prospective cohort study was performed of all live births who weighed > or =500 g for a 2-year period (1999-2000) at a large metropolitan hospital (n = 10,027 births). Factors that were associated significantly with cesarean delivery at one time excluded cases in which cesarean delivery was a necessary or probable outcome. In the planned vaginal delivery sample (n = 7940 births), a risk-adjusted logistic regression model was used to assess the prediction of cesarean delivery. To test for the effect of physician-management physician, we used the subset of physicians with > or =45 deliveries in the 2-year time period (n = 6563 deliveries).

RESULTS

When physician-management physician data were added to the use of forward stepwise regression, entry order was abnormal position, nulliparity, birth weight of >4000 g, and physician. The model's predictive ability improved from 43.8% to 50.2%.

CONCLUSION

Physician management adds a significant independent effect to the cesarean delivery risk model.

Analgesia and cesarean delivery rates

Various studies report conflicting data with regard to the level of risk of cesarean delivery for nulliparous women who receive epidural analgesia before 5 cm of cervical dilatation. As a result, some institutions are requiring that laboring women reach 4-5 cm of dilatation before receiving epidural analgesia. The American College of Obstetricians and Gynecologists wishes to reaffirm the opinion published jointly with the American Society of Anesthesiologists that while under a physician's care, in the absence of a medical contraindication, maternal request is a sufficient medical indication for pain relief during labor Decisions regarding analgesia should be coordinated among the obstetrician, the anesthesiologist, the patient, and support personnel.