Epidural use in labour is not associated with an increased risk of maternal or neonatal morbidity when the second stage is prolonged

Inconsistent definitions of prolonged labor in international literature: a scoping review

Objective

Prolonged labor is the commonest indication for intrapartum cesarean section, but definitions are inconsistent and some common definitions were recently found to overestimate the speed of physiological labor. The objective of this review is to establish an overview of synonyms and definitions used in the literature for prolonged labor, separated into first and second stages, and establish types of definitions used.

Data sources

A systematic search was conducted in PubMed, Embase, Web of Science, Cochrane Library, Emcare, and Academic Search Premier.

Study eligibility criteria

All articles in English that (1) attempted to define prolonged labor, (2) included a definition of prolonged labor, or (3) included any synonym for prolonged labor, were included.

Methods

Data on study design, year of publication, country or region of origin, synonyms used, definition of prolonged first and/or second stage, and origin of provided definition (if not primarily established by the study) were collected into a database.

Results

In total, 3402 abstracts and 536 full-text papers were screened, and 232 papers were included. Our search established 53 synonyms for prolonged labor. Forty-three studies defined prolonged labor and 189 studies adopted a definition of prolonged labor. Definitions for prolonged first stage of labor were categorized into: time-based (n=14), progress-based (n=12), clinician-based (n=5), or outcome-based (n=4). For the 33 studies defining prolonged second stage, the majority of definitions (n=25) were time-based, either based on total duration or duration of no descent of the presenting part.

Conclusions

Despite efforts to arrive at uniform labor curves, there is still little uniformity in definitions of prolonged labor. Consensus on which definition to use is called for, in order to safely and respectfully allow physiological labor progress, ensure timely management, and assess and compare incidence of prolonged labor between settings.

Factors associated with spontaneous vaginal birth in nulliparous women: A descriptive systematic review

PROBLEM

Spontaneous vaginal birth (SVB) rates for nulliparous women are declining internationally.

BACKGROUND

There is inadequate understanding of factors affecting this trend overall and limited large-scale responses to improve women's opportunity to birth spontaneously.

AIM

To undertake a descriptive systematic review identifying factors associated with spontaneous vaginal birth at term, in nulliparous women with a singleton pregnancy.

METHODS

Quantitative studies of all designs, of nulliparous women with a singleton pregnancy and cephalic presentation, who experienced a SVB at term were included. Nine databases were searched (inception to October 2022). Two reviewers undertook quality appraisal; Randomised Controlled Trials (RCTs) with high risk of bias (ROB 2.0) and other designs with (QATSDD) scoring ≤ 50% were excluded.

FINDINGS

Data were abstracted from 90 studies (32 RCTs, 39 cohort, 9 cross-sectional, 4 prevalence, 5 case control, 1 quasi-experimental). SVB rates varied (13%-99%). Modifiable factors associated with SVB included addressing fear of childbirth, low impact antenatal exercise, maternal positioning during second-stage labour and midwifery led care. Complexities arising during pregnancy and regional analgesia were shown to decrease SVB and other interventions, such as routine induction of labour were equivocal.

DISCUSSION

Antenatal preparation (low impact exercise, childbirth education, addressing fear of childbirth) may increase SVB, as does midwifery continuity-of-care. Intrapartum strategies to optimise labour progression emerged as promising areas for further research.

CONCLUSION

Declining SVB rates may be improved through multi-factorial approaches inclusive of maternal, fetal and clinical care domains. However, the variability of SVB rates testifies to the complexity of the issue.

Differences in rates of severe perineal trauma between midwife-led and obstetrician-led care in the Netherlands: A nationwide cohort study

Objective

To investigate trends and rates of severe perineal trauma (SPT), also known as obstetric anal sphincter injury (OASI), between midwife-led and obstetrician-led care in the Netherlands, and factors associated with SPT.

Methods

This nationwide cohort study included registry data from 2000 to 2019 (n = 2,169,950) of spontaneous vaginal births of term, live, cephalic, single infants, without a (previous) caesarean section or assisted vaginal birth.First, trends of SPT and episiotomy were shown. Second, differences in SPT rates between midwife- and obstetrician-led care were assessed. Third, associations of care factors with SPT were examined. Multivariable logistic regression analyses were used to determine which factors were important in the associations. All outcomes were stratified for parity.

Results

Over time, the SPT incidence increased mainly in midwife-led care and episiotomy rates decreased. Compared to midwife-led care, SPT rates were lower in obstetrician-led care among primiparous women (aOR 0.78; 99 % CI 0.74-0.81) and comparable among multiparous women (aOR 1.04; 99 % CI 0.99-1.10). Among women without epidural analgesia, these differences were smaller for primiparous women (aOR 0.88; 99 % CI 0.84-0.92), but the SPT rate was higher in obstetrician-led care among multiparous women (aOR 1.09; 99 % CI 1.03-1.15). Among women without shoulder dystocia, induction, augmentation, and pain medication, SPT rates were comparable among primiparous women, but higher among multiparous women in obstetrician-led care. In midwife-led care, SPT occurred more often among hospital versus home births. In obstetrician-led care, lower SPT incidences were found among births with epidural analgesia and for multiparous women with induction or augmentation.

Conclusions

Iinduction, augmentation, and epidural analgesia in obstetrician-led care may be an explanatory factor for the higher incidence of SPT among primiparous women in midwife-led care. More research is needed to explain differences in SPT rates and to understand how SPT can be prevented, while maintaining a high intact perineum rate.

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.

Oxytocin Administration in Low-Risk Women, a Retrospective Analysis of Birth and Neonatal Outcomes

BACKGROUND

In recent years, higher than the recommended rate of oxytocin use has been observed among low-risk women. This study examines the relationship between oxytocin administration and birth outcomes in women and neonates.

METHODS

A retrospective analysis of birth and neonatal outcomes for women who received oxytocin versus those who did not. The sample included 322 women with a low-risk pregnancy.

RESULTS

Oxytocin administration was associated with cesarean section (aOR 4.81, 95% CI: 1.80-12.81), instrumental birth (aOR 3.34, 95% CI: 1.45-7.67), episiotomy (aOR 3.79, 95% CI: 2.20-6.52) and length of the second stage (aOR 00:18, 95% CI: 00:04-00:31). In neonatal outcomes, oxytocin in labor was associated with umbilical artery pH ≤ 7.20 (OR 3.29, 95% CI: 1.33-8.14). Admission to neonatal intensive care unit (OR 0.56, 95% CI: 0.22-1.42), neonatal resuscitation (OR 1.04, 95% CI: 0.22-1.42), and Apgar score <7 (OR 0.48, 95% CI: 0.17-1.33) were not associated with oxytocin administration during labor.

CONCLUSIONS

Oxytocin administration during labor for low-risk women may lead to worse birth outcomes with an increased risk of instrumental birth and cesarean, episiotomy and the use of epidural analgesia for pain relief. Neonatal results may be also worse with an increased proportion of neonates displaying an umbilical arterial pH ≤ 7.20.

Association between Neuraxial Labor Analgesia and Neonatal Morbidity after Operative Vaginal Delivery

BACKGROUND

Up to 84% of women who undergo operative vaginal delivery receive neuraxial analgesia. However, little is known about the association between neuraxial analgesia and neonatal morbidity in women who undergo operative vaginal delivery. The authors hypothesized that neuraxial analgesia is associated with a reduced risk of neonatal morbidity among women undergoing operative vaginal delivery.

METHODS

Using United States birth certificate data, the study identified women with singleton pregnancies who underwent operative vaginal (forceps- or vacuum-assisted delivery) in 2017. The authors examined the relationships between neuraxial labor analgesia and neonatal morbidity, the latter defined by any of the following: 5-min Apgar score less than 7, immediate assisted ventilation, assisted ventilation greater than 6 h, neonatal intensive care unit admission, neonatal transfer to a different facility within 24 h of delivery, and neonatal seizure or serious neurologic dysfunction. The authors accounted for sociodemographic and obstetric factors as potential confounders in their analysis.

RESULTS

The study cohort comprised 106,845 women who underwent operative vaginal delivery, of whom 92,518 (86.6%) received neuraxial analgesia. The proportion of neonates with morbidity was higher in the neuraxial analgesia group than the nonneuraxial group (10,409 of 92,518 [11.3%] vs. 1,271 of 14,327 [8.9%], respectively; P < 0.001). The unadjusted relative risk was 1.27 (95% CI, 1.20 to 1.34; P < 0.001); after accounting for confounders using a multivariable model, the adjusted relative risk was 1.19 (95% CI, 1.12 to 1.26; P < 0.001). In a post hoc analysis, after excluding neonatal intensive care unit admission and neonatal transfer from the composite outcome, the effect of neuraxial analgesia on neonatal morbidity was not statistically significant (adjusted relative risk, 1.07; 95% CI, 1.00 to 1.16; P = 0.054).

CONCLUSIONS

In this population-based cross-sectional study, a neonatal benefit of neuraxial analgesia for operative vaginal delivery was not observed. Confounding by indication may explain the observed association between neuraxial analgesia and neonatal morbidity, however this dataset was not designed to evaluate such considerations.

EDITOR’S PERSPECTIVE

Obstetric anal sphincter injuries (OASIS) in multiparous women with the use of epidural anaesthesia: A retrospective cohort study

BACKGROUND

The use of epidural as a form of analgesia is increasingly common in labour, but this has shown to have been associated with increased rates of instrumental delivery, and prolonged second stage, resulting in increased rates of OASIS (Obstetric Anal Sphincter Injury).

AIMS

This study aimed to investigate the impact of epidural anaesthesia in multiparous women undergoing vaginal deliveries on OASIS and secondary maternal outcomes.

MATERIALS AND METHODS

A retrospective cohort study of multiparous women with singleton pregnancies delivering at term ≥37 weeks and the use of epidural analgesia in labour at a tertiary hospital in Melbourne, Victoria, Australia, the Royal Women's Hospital was undertaken between the period 2012-2018. Maternal outcomes were collated and dichotomised according to the presence of epidural use. Multiparous women with no prior history of a vaginal birth and non-cephalic presentation during labour were excluded.

RESULTS

There were 14 124 multiparous women who met the inclusion criteria; spontaneous labour is associated with an increased risk of OASIS at adjusted odds ratio (aOR) 1.46, P = 0.012. The overall rate of epidural use was 17%. Women with epidural use had significantly lower chances of sustaining OASIS in normal vaginal births and instrumental vaginal births. (1% vs 1.8%, aOR 0.49, P = 0.004). Epidural is associated with increased rates of prolonged second stage (8.5% vs 3.8%, P < 0.05), instrumental delivery (26.1% vs 4%, P < 0.05), and episiotomy use (23.8% vs 10.2%, P < 0.05).

CONCLUSION

The use of epidural analgesia in multiparous women is associated with a reduction in anal sphincter injuries.

Pregnant women's clinical characteristics, intrapartum interventions, and duration of labour in urban China: a multi-center cross-sectional study

BACKGROUND

There is an increasing global trend towards the widespread over-medicalisation of labour and childbirth. The present study aimed to investigate pregnant women's clinical characteristics, intrapartum interventions, duration of labour and its associated factors; and to compare the differences of these variables between nulliparas and multiparas in China.

METHODS

A multi-center cross-sectional study was carried out in three tertiary hospitals of Fudan University in Shanghai, China. A total of 1523 participants were approched and assessed for eligibility. Data on women's sociodemographic characteristics, intrapartum interventions, and duration of labour were measured and collected. Kaplan-Meier survival analysis was performed to present the curves of total duration of labour by parity. After z-transformation of labour duration, multivariable linear regression was used to control for confounding and to identify independent associations between potential associated factors and the primary outcome of labour duration.

RESULTS

Overall, 1209 eligible women agreed to participate and were investigated. Rates of different intrapartum interventions were 27.4% in use of amniotomy, 37.9% in use of oxytocin, 53.0% in continuous electronic fetal monitoring, and 52.9% in epidural use, respectively. The curve of total duration of labour was significantly different between nulliparas and multiparas (P < .001). Of the 1209 participants, 983 (81.3%) women eventually achieved successful vaginal birth while 226 (18.7%) women ended in intrapartum caesarean section. The median duration of total stage of labour was significantly longer in the nulliparous group [9.38 (6.33,14.10) hours] than that in the multiparous group [5.08 (3.00,7.83) hours] (P < .001). The following factors were independently associated with longer duration of total stage of labour: epidural analgesia (P < .001), primiparity (P < .001), continuous electronic fetal monitoring (P = .035), and increased birth weight (P = .005).

CONCLUSIONS

Intrapartum medical interventions become common obstetric practices in urban China. Multifactorial variables independently associated with longer duration of labour were identified, including epidural analgesia, primiparity, continuous electronic fetal monitoring, and increased birth weight. Further research is required to validate these variables and to determine the modifiable factors for labour management. And models of care with lower intervention rates such as midwife-led models of care should be developed and implemented in China.

Reducing caesarean rates in a public maternity hospital by implementing a plan of action: a quality improvement report

BACKGROUND

Caesarean rates increased in different parts of the world, rising from 20% to 33% in the USA and from 40% to 55% in Brazil between 1996 and 2011; however, there was no reduction in morbimortality rates. Several factors have been suggested as responsible for this increase, such as health judicialisation, fear of the painful process on the patients' part and reduction of medical training in vaginal delivery and labour complications. It is urgent to reverse this process and, therefore, a model of actions was created with the intention of engaging the team in order to reduce caesarean rates in a Brazilian hospital.

METHODOLOGY

The model was based on the following actions: encouragement of labour analgesia; execution of written reports of any cardiotocographic examination; plan-do-study-act cycles for nursing orientations about the positions that favour pregnant women during labour; creation of a birth induction form; monthly feedback with physicians and nurses on caesarean rates achieved; verification of the caesarean rate by medical staff with individual feedback; daily round of medical coordination for case discussions; disclosure of caesarean rates on hospital posters; and constant dissemination of literature with strategies to reduce caesarean delivery. This plan of action started in January 2016. The mean caesarean section rate in the 31 months preceding the interventions (period A) was then compared with the 31 subsequent months (period B).

RESULTS

Both periods presented caesarean rates with normal distribution. The mean caesarean rate was 29.24% (range: 38.69%-23.89%, SD 3.24%) vs 25.84% (range: 17.96%-34.97%, SD 3.92%, p<0.05), respectively, for periods A and B.

CONCLUSION

After the implementation of the plan of action, there was a reduction in caesarean rates in this hospital.

Effect of music on labor and delivery in nulliparous singleton pregnancies: a randomized clinical trial

BACKGROUND

Women's experience of pain during labor varies greatly, and pain control is a major concern for obstetricians. Several methods have been studied for pain management for women in labor, including drug and non-drug interventions.

OBJECTIVE

To test the hypothesis that in nulliparous women with singleton pregnancies at term, listening to music would reduce the pain level during labor.

METHODS

Parallel group non-blinded randomized clinical trial conducted at a single center in Italy. Nulliparous women in spontaneous labor with singleton pregnancies and vertex presentation admitted in labor and delivery room between 37 0/7 and 42 0/7 weeks of gestation for active phase of labor were eligible, and were randomized in a 1:1 ratio to receive music during labor or no music during labor. Music in labor was defined listening to music from the randomization until the delivery of the baby. The primary endpoint was the pain level during the active phase of labor, recorded using the visual analogue scale (VAS) for pain, ranging from 0 (no pain) to 10 (unbearable pain). The effect of music use during labor on each outcome was quantified as the mean difference (MD) with 95% confidence interval (CI).

RESULTS

During the study period, 30 women agree to take part in the study, underwent randomization, and were enrolled and followed up. 15 women were randomized in the music group, and 15 in the control group. No patients were lost to follow up for the primary outcome. Pain level during the active phase of labor was scored 8.8 ± 0.9 in the music group, and 9.8 ± 0.3 in the control group (MD - 1.00 point, 95% CI - 1.48 to - 0.52; P < 0.01). Music during labor and delivery was also associated with a decreased pain at 1 h postpartum (MD - 2.40 points, 95% CI - 4.30 to - 0.50), and decreased anxiety level during active phase of labor (MD - 19.90 points, 95% CI - 38.72 to - 1.08), second stage of labor (MD - 49.40 points, 95% CI - 69.44 to - 29.36), and at 1 h postpartum (MD - 27.00 points, 95% CI - 47.37 to - 6.63).

CONCLUSION

In nulliparous women with singleton pregnancies at term, listening to music reduces the pain level, and the anxiety level during labor.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03779386.