Epidural analgesia need not increase operative delivery rates

OBJECTIVE: We sought to examine the relationship between epidural analgesia and cesarean and instrumental vaginal delivery rates. STUDY DESIGN: This is a retrospective analysis of the first 1000 nulliparous pregnancies in women with a cephalic presentation in spontaneous labor at term in each of 3 different years, over which the epidural rate increased from 10% to 57%. RESULTS: Cesarean and instrumental vaginal delivery rates were similar in all 3 years. Demographic characteristics remained unchanged or altered in a manner that has previously been associated with an increase in intervention. Electronic fetal monitoring and first-stage oxytocin use remained unchanged, but oxytocin use in the second stage increased considerably. CONCLUSIONS: Increased use of epidural analgesia had no effect on cesarean delivery rates. Although randomized trials have suggested that it increases instrumental vaginal delivery rates, this might be overcome by active management of labor or judicious use of oxytocin in the second stage.     

Does epidural analgesia prolong labor and increase risk of cesarean delivery? A natural experiment

OBJECTIVE: More than 50% of pregnant women in the United States are using epidural analgesia for labor pain. However, whether epidural analgesia prolongs labor and increases the risk of cesarean delivery remains controversial. STUDY DESIGN: We examined this question in a community-based, tertiary military medical center where the rate of continuous epidural analgesia in labor increased from 1% to 84% in a 1-year period while other conditions remained unchanged-a natural experiment. We systematically selected 507 and 581 singleton, nulliparous, term pregnancies with spontaneous onset of labor and vertex presentation from the respective times before and after the times that epidural analgesia was available on request during labor. We compared duration of labor, rate of cesarean delivery, instrumental delivery, and oxytocin use between these two groups. RESULTS: Despite a rapid and dramatic increase in epidural analgesia during labor (from 1% to 84% in 1 year), rates of cesarean delivery overall and for dystocia remained the same (for overall cesarean delivery: adjusted relative risk, 0.8; 95% confidence interval, 0.6-1.2; for dystocia: adjusted relative risk, 1.0; 95% confidence interval, 0.7-1.6). Overall instrumental delivery did not increase (adjusted relative risk, 1.0; 95% confidence interval, 0.8-1.4), nor did the duration of the first stage and the active phase of labor (multivariate analysis; P >.1). However, the second stage of labor was significantly longer by about 25 minutes (P <.001). CONCLUSION: Epidural analgesia during labor does not increase the risk of cesarean delivery, nor does it necessarily increase oxytocin use or instrumental delivery caused by dystocia. The duration of the active phase of labor appears unchanged, but the second stage of labor is likely prolonged. (Am J Obstet Gynecol 2001;185:128-34).     

Influence of persistent occiput posterior position on delivery outcome.

OBJECTIVE: To evaluate the influence of intrapartum persistent occiput posterior position of the fetal head on delivery outcome and anal sphincter injury, with reference to the association with epidural analgesia. METHODS: We conducted a prospective observational study of 246 women with persistent occiput posterior position in labor during a 2-year period, compared with 13,543 contemporaneous vaginal deliveries with occiput anterior position. RESULTS: The incidence of persistent occiput posterior position was significantly greater among primiparas (2.4%) than multiparas (1.3%; P <.001; 95% confidence interval 1.4, 2.4) and was associated with significantly higher incidences of prolonged pregnancy, induction of labor, oxytocin augmentation of labor, epidural use, and prolonged labor. Only 29% of primiparas and 55% of multiparas with persistent occiput posterior position achieved spontaneous vaginal delivery, and the malposition was associated with 12% of all cesarean deliveries performed because of dystocia. Persistent occiput posterior position was also associated with a sevenfold higher incidence of anal sphincter disruption. Despite a high overall incidence of use of epidural analgesia (47% versus 3%), the institutional incidence of persistent occiput posterior position was lower than that reported 25 years ago. CONCLUSION: Persistent occiput posterior position contributed disproportionately to cesarean and instrumental delivery, with fewer than half of the occiput posterior labors ending in spontaneous delivery and the position accounting for 12% of all cesarean deliveries for dystocia. Persistent occiput posterior position leads to a sevenfold increase in the incidence of anal sphincter injury. Use of epidural analgesia was not related to the malposition.     

A meta-analysis of upright positions in the second stage to reduce instrumental deliveries in women with epidural analgesia

BACKGROUND: Epidural analgesia is associated with an increased risk of instrumental delivery. We, in this study, present a systematic review in order to assess the effectiveness of maintaining an upright position during the second stage of labor to reduce instrumental deliveries among women choosing epidural analgesia. The study population included women with uncomplicated pregnancies at term with epidural analgesia established in the first stage of labor. METHODS: We searched MEDLINE, EMBASE, and CINAHL databases and the Cochrane Trials Register up to July 2003 and cross-checked the reference lists of published studies. Trial eligibility and outcomes were pre-specified. Group tabular data were obtained for each trial and were analyzed by using meta-analytic techniques. RESULTS: Only two studies were included with data on 281 women (166 upright and 115 recumbent). Upright positions in the second stage were associated with a non-significant reduction in the risk of both instrumental delivery (relative risk (RR) = 0.77, 95% confidence interval (CI) = 0.46-1.28) and cesarean section (RR = 0.57, 95% CI = 0.28-1.16). Both studies reported a statistically significant reduction in labor duration associated with upright positions. Data on other outcomes, including perineal trauma, postpartum hemorrhage, maternal satisfaction, and infant well-being, were insufficient. CONCLUSIONS: There were insufficient data to show a significant benefit from upright positions in the second stage of labor for women who choose epidural or to evaluate safety aspects. However the magnitude of the reductions in instrumental delivery and cesarean section warrants an adequately powered randomized, controlled trial to fully evaluate the practice of upright positions in the second stage for women with an epidural.     

Maternal and neonatal outcomes after oxytocin augmentation in patients undergoing a trial of labor after prior cesarean delivery.

OBJECTIVE: To study the safety of oxytocin augmentation in patients having abnormal labors after a prior cesarean delivery. METHODS: We retrospectively analyzed a case series of women undergoing a trial of labor after a previous cesarean delivery from the University of California San Francisco perinatal data base. Women whose labors were augmented with oxytocin were compared to women with labor abnormalities managed without the use of oxytocin. A wide range of maternal and neonatal outcomes was compared. Only vertex singleton term deliveries were studied. RESULTS: From 1975-1990 there were 504 trials of labor, of which 185 (37%) had labor abnormalities; 62 of these 185 (34%) were augmented with oxytocin. Fifty-eight percent of the trials of labor ended in vaginal delivery. In patients since 1982, 73% delivered vaginally. Forty-six (74%) of augmented patients delivered vaginally. There were no maternal deaths, uterine ruptures, or hysterectomies. Estimated blood loss was slightly greater among augmented patients after controlling for mode of delivery (P < .05), but only by 50-100 mL on average. There was no difference in the need for maternal transfusion. Fetal trauma and fetal scalp blood sampling occurred more frequently (P < .05) in the augmented labors, but only in the subgroup delivered by cesarean. No increased risk was demonstrated by a comparison between patients receiving oxytocin and epidural anesthesia and patients with labor abnormalities receiving neither. CONCLUSION: Retrospective analysis supports the use of oxytocin and epidural anesthesia to augment abnormal trials of labor after prior cesarean.     

Labor course and delivery in epidural analgesia: a case-control study.

BACKGROUND: We aimed to establish if epidural analgesia is associated with a higher incidence of operative vaginal delivery, longer duration of labor and more frequent use of oxytocin than labor without analgesia. METHODS: We analyzed a cohort of 207 women with no risk factors who delivered with epidural analgesia in the labor unit of Spedali Civili, Brescia, Italy, during 2001. Length of the first and second stage of labor, mode of delivery, neonatal cord blood pH, neonatal Apgar score and neonatal outcomes were evaluated. RESULTS: Epidural analgesia was performed on request in 6%: in this group (group A) there were 141 (68%) nulliparae and 66 (32%) pluriparae; mean ( +/- standard deviation) gestational age at delivery was 39.4 +/- 1.3 weeks (range: 34.1-41.5 weeks). In this group, 184 (89%) had vaginal delivery and 23 (11%) delivered by Cesarean section. Among controls (group B), 368 (89%) had a vaginal delivery and 46 (11%) delivered by Cesarean section; vacuum extraction was used in 18 deliveries (9%) in group A and in 13 deliveries (3%) in group B. The duration of the second stage of spontaneous labor in the nulliparae of group A was significantly longer than in group B. No statistically significant differences were found between mean umbilical artery pH values of groups A and B. CONCLUSION: Our results confirm that epidural analgesia does not affect the rate of Cesarean delivery, while increasing the use of oxytocin augmentation, the duration of the second stage of labor and the rate of instrumental vaginal delivery.     

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.     

Rate of uterine rupture during a trial of labor in women with one or two prior cesarean deliveries.

OBJECTIVE: We sought to determine whether there is a difference in the rate of symptomatic uterine rupture after a trial of labor in women who have had 1 versus 2 prior cesarean deliveries. STUDY DESIGN: The medical records of all women with a history of either 1 or 2 prior cesarean deliveries who elected to undergo a trial of labor during a 12-year period (July 1984-June 1996) at the Brigham and Women's Hospital were reviewed. Rates of uterine rupture were compared for these 2 groups. Potential confounding variables were controlled by using logistic regression analyses. RESULTS: Women with 1 prior cesarean delivery (n = 3757) had a rate of uterine rupture of 0.8%, whereas women with 2 prior cesarean deliveries (n = 134) had a rate of uterine rupture of 3.7% (P =.001). In a logistic regression analysis that was controlled for maternal age, use of epidural analgesia, oxytocin induction, oxytocin augmentation, the use of prostaglandin E(2) gel, birth weight, gestational age, type of prior hysterotomy, year of trial of labor, and prior vaginal delivery, the odds ratio for uterine rupture in those patients with 2 prior cesarean deliveries was 4.8 (95% confidence interval, 1.8-13. 2) CONCLUSIONS: Women with a history of 2 prior cesarean deliveries have an almost 5-fold greater risk of uterine rupture than those with only 1 prior cesarean delivery.     

Epidural analgesia and the course of delivery in term primiparas

OBJECTIVES: Epidural analgesia provides the most effective pain control during labor. Of great concern is its influence on the course of delivery and perinatal complications. DESIGN: The aim of the study was to assess the effect of epidural analgesia on the course of delivery and perinatal outcome. MATERIALS AND METHODS: 609 deliveries among 1334 (323 women with epidural analgesia (53%) and 548 without epidural analgesia (47%)) met the following criteria: primipara, singleton, live pregnancy, > =37 weeks' gestation, cephalic presentation of a fetus, lack of contraindication for vaginal delivery. The incidence of instrumental deliveries and fetal distress, duration of the first, second and third stage of labor, perinatal outcome, perinatal complications and perinatal blood loss and were analyzed. RESULTS: The incidence of fetal distress during second stage of labor was significantly higher in the epidural group (12.69 vs. 6.99%, P=0.02). The incidence of fetal distress during first stage of labor did not differ in both groups (10.53% vs. 8.74%, NS). Cesarean sections rate was similar in epidural and non-epidural group (17.7 vs. 18.2%, NS). Among vaginal deliveries duration of the first and second stage of labor was longer in epidural group (6.5+/-2.4 vs. 5.4+/-2.5 godz., P=0,000003 and 47.3+/-34.8 vs. 29.1+/-25.8 min., P=0.000003) and this was independent of period of time between onset of first stage of labor and epidural analgesia. Oxitocin use was significantly more frequent in the epidural group (20.6 vs. 10.3%, P<0.004). There were no statistically significant differences in the rates of instrumental vaginal deliveries, 1 and 5-minute Apgar scores, length of third stage of labor and perinatal blood loss in patients with and without epidural analgesia. Perinatal outcome did not depend on previous use of epidural analgesia or mode of analgesia for the operation in cesarean section subgroup. CONCLUSION: Epidural labor analgesia is associated with slower progress of labor but has no adverse effect on perinatal outcome and perinatal complications.     

Trial of labor without oxytocin in patients with a previous cesarean section

In a 30-month period, 261 of 557 (46.8%) patients underwent a trial of labor. Of these, 215 patients (82.4%) achieved vaginal delivery. The major controversial issues regarding vaginal delivery in patients with a prior cesarean section are oxytocin administration, the inclusion of patients with recurring indications, and the use of epidural analgesia. Oxytocin was not used in this study. When our results were compared to those of others who used oxytocin liberally we found that oxytocin augmentation was not a major factor in increasing significantly the success and vaginal delivery rate. We believe that oxytocin usage should be reserved for selected patients with well-defined indications. When the primary cesarean section was for cephalopelvic disproportion, 66.6% delivered vaginally. This success rate justifies the inclusion of these patients in a trial of labor. Epidural analgesia proved to be a safe and efficient procedure. There was no maternal or perinatal mortality related to trial of labor.     

Does epidural anesthesia affect the course of labor and delivery?

The progress of labor ideally leads to a normal, spontaneous, vaginal delivery. Many factors--maternal, fetal, obstetrical and anesthetic--may collectively contribute to delaying or precluding an ideal outcome. Adverse outcomes of labor and delivery must be clearly defined in terms of maternal, fetal, or neonatal morbidity or mortality, and should be distinguished from abnormal data (such as fetal heart rate, duration of labor, and incidence of low forceps deliveries) that are only indirectly related to outcome. Epidural anesthesia is not a singular phenomenon. Variations and subtle nuances in the administration of epidural anesthesia create a vast array of potential anesthetic regimens. To discover the anesthetic methods that provide excellent analgesia with no adverse effects on the course of labor is an ideal goal that has not yet been achieved. To approach this goal, the answers to several questions are needed. Are study patient groups adequately matched for risk factors? Are obstetrical practices well-defined with respect to elective versus indicated use of instrumental or cesarean delivery methods? Do the risks of instrumental delivery outweigh the benefit of perineal analgesia associated with epidural anesthesia? Is it possible to provide optimal analgesia throughout stage two labor without tending to increase the risk of instrumental delivery? Can delayed pushing during stage two labor increase the probability of spontaneous vaginal delivery with continuous epidural anesthesia? Well-controlled clinical trials and refinements in both anesthetic and obstetric techniques are necessary to resolve such issues so that every parturient (and fetus) may undergo a safe and painless delivery.     

Epidural analgesia with sufentanil during labor and operative delivery

BACKGROUND: It has been argued that by adding an opioid to the local anesthetic drug used for epidural analgesia during childbirth, one can reduce the risk of operative delivery. Objective. In a population-based observational study, to evaluate the effect of adding an opioid to a local anesthetic drug on the risk of instrumental delivery or cesarean section. DESIGN: Comparison of delivery units adding/not adding opioid to the local anesthetic for epidural analgesia in labor. SETTING: All deliveries using epidural analgesia in Sweden during 1992-96 were evaluated on the basis of information stored at the Medical Birth Registry, the National Board of Health and Welfare, Stockholm. METHOD: A questionnaire was sent to all delivery units (n=61), as well as to the Head of corresponding Anesthesiology Department in each hospital, requesting information regarding the period when opioids (sufentanil) were first added to the local epidural analgesic. Parturients given epidural analgesia were divided into three time-related groups: those delivered before the introduction of opioids (n=34,071), when opioids were first added (n=7,236), and since the introduction of opioids (n=44,384). Odds ratio (OR) with 95% confidence interval (CI) was used to assess the effect of sufentanil versus no sufentanil, on the risk of operative delivery. The parturients were stratified for year of delivery, age, and parity. Main outcome measures. Instrumental delivery, cesarean section, length of stay in hospital post partum. RESULTS: A significant reduction was observed in the incidence of instrumental delivery (OR 0.72; 95% CI 0.68-0.76). A similar though less pronounced effect was evident concerning the risk of cesarean section for nulliparae (OR 0.79; 95% CI 0.72-0.88) but not for multiparae (OR 0.93; 95% CI 0.80-1.07). Fewer women with an opioid added to the local anesthetic spent more than 4 (or more than 7) days in hospital post partum, compared with those given epidural analgesia without an opioid. CONCLUSION: When added to the local anesthetic used for epidural analgesia, as in Sweden during the last 5 years, opioids appear to reduce the incidence of instrumental delivery and cesarean section and also the post partum hospital stay.     

Uterine rupture during induced or augmented labor in gravid women with one prior cesarean delivery.

OBJECTIVE: Our purpose was to examine the risk of uterine rupture during induction or augmentation of labor in gravid women with 1 prior cesarean delivery. STUDY DESIGN: The medical records of all gravid women with history of cesarean delivery who attempted a trial of labor during a 12-year period at a single center were reviewed. The current analysis was limited to women at term with 1 prior cesarean delivery and no other deliveries. The rate of uterine rupture in gravid women within that group undergoing induction was compared with that in spontaneously laboring women. The association of oxytocin induction, oxytocin augmentation, and use of prostaglandin E(2) gel with uterine rupture was determined. Logistic regression analysis was used to examine these associations, with control for confounding factors. RESULTS: Of 2774 women in the analysis, 2214 had spontaneous onset of labor and 560 women had labor induced with oxytocin or prostaglandin E(2) gel. The overall rate of rupture among all patients with induction of labor was 2.3%, in comparison with 0.7% among women with spontaneous labor (P =.001). Among 1072 patients receiving oxytocin augmentation, the rate of uterine rupture was 1.0%, in comparison with 0.4% in nonaugmented, spontaneously laboring patients (P =.1). In a logistic regression model with control for birth weight, use of epidural, duration of labor, maternal age, year of delivery, and years since last birth, induction with oxytocin was associated with a 4.6-fold increased risk of uterine rupture compared with no oxytocin use (95% confidence interval, 1.5-14.1). In that model, augmentation with oxytocin was associated with an odds ratio of 2.3 (95% confidence interval, 0.8-7.0), and use of prostaglandin E(2) gel was associated with an odds ratio of 3.2 (95% confidence interval, 0.9-10.9). These differences were not statistically significant. CONCLUSION: Induction of labor with oxytocin is associated with an increased rate of uterine rupture in gravid women with 1 prior uterine scar in comparison with the rate in spontaneously laboring women. Although the rate of uterine rupture was not statistically increased during oxytocin augmentation, use of oxytocin in such cases should proceed with caution.     

罗哌卡因用于分娩镇痛对产程和分娩方式的影响

目的探讨罗哌卡因用于分娩镇痛对产妇产程和分娩方式的影响。方法采用回顾性分析的方法,选择行0.1%罗哌卡因+芬太尼(1μg/ml)硬膜外阻滞的190例健康、单胎、足月临产初产妇为镇痛组。另选择同期222例条件相似、未行任何镇痛措施的自然临产产妇为对照组。记录两组产妇产程时间、分娩方式、新生儿1分钟和5分钟Apgar评分。结果(1)产程时间比较:镇痛组第一产程、第二产程和总产程时间分别为(426±161)min、(54±27)min、(489±166)min;对照组分别为(364±167)min、(37±22)min、(409±170)min,两组比较,差异均有统计学意义(P<0.01)。(2)分娩方式比较:镇痛组阴道器械助产率为20.0%(38/190),明显高于对照组的6.3%(14/222),两组比较,差异均有统计学意义(P<0.01);镇痛组剖宫产率及阴道顺产率分别为20.0%(38/190)、60.5%(115/190),对照组分别为28.4%(63/222)、65.8%(146/222),两组比较,差异均无统计学意义(P>0.05)。(3)Apgar评分比较:镇痛组新生儿1分钟及5分钟Apgar评分<7分者分别为7.9%(15/190)、2.6%(5/190),对照组分别为4.5%(10/222)、0.5%(1/222),两组比较,差异均无统计学意义(P>0.05)。结论罗哌卡因用于分娩镇痛对产妇产程有延长作用及增加阴道器械助产率,但对新生儿出生结局无明显影响。     

Epidural analgesia and severe perineal tears: a literature review and large cohort study

Abstract

Objective: Our objectives were to study the association between epidural analgesia and risk of severe perineal tears (SPT), and identify additional risk factors for SPT.

Methods: We conducted a historical cohort study of women with term delivery between 2006 and 2011. Inclusion criteria were an uncomplicated singleton pregnancy, cephalic presentation and vaginal delivery. Multivariate logistic regression models were constructed to study the association between epidural analgesia and SPT, controlling for potential confounders. Additional models studied the association between prolonged second stage and instrumental labor and SPT.

Results: During the study period, 61?308 eligible women gave birth, 31?631 (51.6%) of whom received epidural analgesia. SPT occurred in 0.3% of births. Deliveries with epidural had significantly higher rates of primiparity, induction and augmentation of labor, prolonged second stage of labor, instrumental births and midline episiotomies. The univariate analysis showed a significant association between the use of epidural and SPT (OR: 1.78, 95% CI: 1.34–2.36); however, this association disappeared when parity was introduced (OR: 0.95, 95% CI: 0.69–1.29). Instrumental deliveries and prolonged second stage of labor were both strongly associated with SPT (ORs of 1.82 and 1.77)

Conclusions: Epidural analgesia was not associated with SPT once confounding factors were controlled for.     

Emergency cesarean delivery in induction of labor: an evaluation of risk factors

BACKGROUND: Induction of labor has been associated with an increased risk of emergency cesarean delivery. Knowledge of factors that influence the risk of cesarean delivery in women with induced labor is limited. METHODS: We performed a case-control study, nested within a population-based cohort of women with induced labor at term during 1991-1996 in Uppsala County, Sweden. Cases were women delivered with emergency cesarean delivery, and controls were women vaginally delivered (n = 193, respectively). Using logistic regression, analyses were performed. Odds ratio (OR) with 95% confidence intervals (CI) was used as a measure of relative risk. RESULTS: Women with a previous cesarean delivery had high risks of cesarean delivery (adjusted OR = 10.10, 95% CI = 3.30-30.92). The risk of cesarean delivery was also increased among nulliparous (adjusted OR = 4.92, 95% CI = 2.81-8.61), short (adjusted OR = 2.20, 95% CI = 1.06-4.59), and obese women (adjusted OR = 2.03, 95% CI = 1.07-3.84). A cervix dilatation less than 1.5 cm doubled the risk of cesarean delivery (adjusted OR = 2.26, 95% CI = 1.09-4.66). Mother's age, epidural analgesia, oxytocin augmentation, gestational age, and birthweight were not significantly associated with risks of cesarean delivery. CONCLUSIONS: Women with a previous cesarean delivery, nulliparous, short, and obese women with induced labor are at high risk of a cesarean delivery. When there is a need to deliver a woman with a previous cesarean section or a nulliparous woman with other risk factors for cesarean delivery, it may be prudent to consider an elective cesarean section.     

Minimum oxytocin dose requirement after cesarean delivery for labor arrest

OBJECTIVE: To estimate the minimum effective intravenous dose of oxytocin required for adequate uterine contraction after cesarean delivery for labor arrest. METHODS: A randomized single-blinded study was undertaken in 30 parturients undergoing cesarean deliveries under epidural anesthesia for labor arrest despite intravenous oxytocin augmentation. Oxytocin was administered as a slow intravenous bolus immediately after delivery of the infant, according to a biased coin up-down sequential allocation scheme. After assisted spontaneous delivery of the placenta, the obstetrician, blinded to the oxytocin dose, assessed uterine contraction as either satisfactory or unsatisfactory. Additional boluses of oxytocin were administered as required, followed by a maintenance infusion. Data were interpreted and analyzed by a logistic regression model at 95% confidence intervals. RESULTS: All patients received oxytocin infusions at a mean +/- standard deviation of 9.8 +/- 6.3 hours before cesarean delivery (maximum infusion dose 10.3 +/- 8.2 mU/min). The minimum effective dose of oxytocin required to produce adequate uterine response in 90% of women (ED90) was estimated to be 2.99 IU (95% confidence interval 2.32-3.67). The estimated blood loss was 1,178 +/- 716 mL. CONCLUSION: Women requiring cesarean delivery for labor arrest after oxytocin augmentation require approximately 3 IU rapid intravenous infusion of oxytocin to achieve effective uterine contraction after delivery. This dose is 9 times more than previously reported after elective cesarean delivery in nonlaboring women at term, suggesting oxytocin receptor desensitization from exogenous oxytocin administration during labor. Therefore, alternative uterotonic agents, rather than additional oxytocin, may achieve superior uterine contraction and control of blood loss during cesarean delivery for labor arrest. LEVEL OF EVIDENCE: I.     

Plasma oxytocin levels in women during labor with or without epidural analgesia: a prospective study

BACKGROUND: Epidural analgesia (EDA) has been reported to prolong labor. Whether this is by interference with endogenous oxytocin release or other mechanisms is unclear. With increasing numbers of women receiving an EDA, it is important to study its effects on labor. The aim was to study the concentration of plasma oxytocin and the progress of labor in women with and without EDA. METHODS: Thirty-four full-term women in spontaneous labor were included, 17 with epidural and 17 controls, matched for cervical dilatation and parity. Oxytocin was measured by radioimmunoassay before analgesia, 60 min later and after placental discharge. No oxytocin augmentation was given during the first hour. RESULTS: EDA during labor was associated with a fall in plasma oxytocin. There was no difference in plasma oxytocin levels between the groups at inclusion. One hour later, oxytocin concentrations had decreased in the epidural and increased in the control group (Student's t-test, p = 0049). The change in oxytocin levels between the first and second sample differed significantly between the groups (ancova, p = 0.028). No difference in cervix dilatation between the groups 1 h after inclusion was noted, but women with EDA had a longer labor compared with those without, especially those with epidural and oxytocin augmentation during the later phase of the first stage of labor. CONCLUSION: EDA during labor may interfere with the release of plasma oxytocin, which may be one mechanism behind prolongation of labor. Larger studies are needed to clarify the effects of epidural analgesia and the role of oxytocin during labor.     

Ambulatory epidural anesthesia and the duration of labor.

OBJECTIVES: Ambulatory epidural analgesia has become a common option for women in labor in France. We tested the hypothesis that a method of epidural analgesia that allowed women to walk had specific advantages regarding mode of delivery, consumption of local anesthetic, oxytocin requirement, and labor duration. METHODS: Two hundred and twenty-one women with uncomplicated pregnancies who presented in spontaneous labor between 36 and 42 weeks of gestation or who were scheduled for induced labor were randomly divided into two groups, ambulatory and non-ambulatory. All were given intermittent epidural injections of 0.1% ropivacaine with 0.6 microg/ml sufentanil for analgesia during labor (P<0.05 was considered significant). None of the women had previous cesarean delivery. RESULTS: There were no significant differences between the two groups in mode of delivery, consumption of local anesthetic, or oxytocin requirement. However, a significant difference was noted in labor duration (173.4+/-109.9 min vs. 236.4+/-130.6 min; P=0.001). CONCLUSIONS: Walking with ambulatory labor analgesia shortens labor duration but has no other effect on the progress and outcome of labor.