Labor patterns in women attempting vaginal birth after cesarean with normal neonatal outcomes

Labor curves based on cervical dilatation over time and their accuracy and effectiveness: A systematic scoping review

OBJECTIVES

This systematic scoping review was conducted to 1) identify and describe labor curves that illustrate cervical dilatation over time; 2) map any evidence for, as well as outcomes used to evaluate the accuracy and effectiveness of the curves; and 3) identify areas in research that require further investigation.

METHODS

A three-step systematic literature search was conducted for publications up to May 2023. We searched the Medline, Maternity & Infant Care, Embase, Cochrane Library, Epistemonikos, CINAHL, Scopus, and African Index Medicus databases for studies describing labor curves, assessing their effectiveness in improving birth outcomes, or assessing their accuracy as screening or diagnostic tools. Original research articles and systematic reviews were included. We excluded studies investigating adverse birth outcomes retrospectively, and those investigating the effect of analgesia-related interventions on labor progression. Study eligibility was assessed, and data were extracted from included studies using a piloted charting form. The findings are presented according to descriptive summaries created for the included studies.

RESULTS AND IMPLICATIONS FOR RESEARCH

Of 26,073 potentially eligible studies, 108 studies were included. Seventy-three studies described labor curves, of which ten of the thirteen largest were based mainly on the United States Consortium on Safe Labor cohort. Labor curve endpoints were 10 cm cervical dilatation in 69 studies and vaginal birth in 4 studies. Labor curve accuracy was assessed in 26 studies, of which all 15 published after 1986 were from low- and middle-income countries. Recent studies of labor curve accuracy in high-income countries are lacking. The effectiveness of labor curves was assessed in 13 studies, which failed to prove the superiority of any curve. Patient-reported health and well-being is an underrepresented outcome in evaluations of labor curves. The usefulness of labor curves is still a matter of debate, as studies have failed to prove their accuracy or effectiveness.

Randomized controlled trial comparing efficacy of a combination regime containing two cervical sensitizers (mifepristone + Foley's catheter) versus single agent mifepristone or Foley's catheter for labor induction in women attempting TOLAC at late third trimester with a dead fetus in utero

Randomized controlled trial comparing efficacy of a combination regime containing two cervical sensitizers (mifepristone + Foley's catheter) versus single agent mifepristone or Foley's catheter for labor induction in women attempting TOLAC at late third trimester with a dead fetus in utero.

AIM

To compare efficacy and safety of a new combination regime comprising of two cervical sensitizers used simultaneously with single agents, for labor induction in women attempting TOLAC at ≥34 weeks' gestation with a dead fetus.

METHOD

This was a multiarm randomized controlled trial (RCT) where participants received one of the three regimes-single agent oral Mifepristone 200 mg, intracervical Foley's catheter (16 Fr size, filled with 40 mL normal saline after intracervical instillation), and combination regime consisting of both used simultaneously. Number of women undergoing vaginal birth within 48 h of induction (VB48 ) was the primary outcome compared between groups.

RESULTS

VB48 was higher in participants on combination regime in comparison to participants on Foley's catheter (54 vs. 42). Total vaginal births were higher in participants on combination regime compared to both single agents (58 vs. 48 and 44). Duration and dose of oxytocin augmentation was lower in participants on combination regime compared to both single agents. Induction birth interval was short in participants on combination regime compared to those on Foley's catheter. Maternal complications between groups were similar.

CONCLUSION

Combination of cervical sensitizers for labor induction in late third trimester among women with dead fetus attempting TOLAC resulted in higher proportion of vaginal births and might reduce risk of scar dehiscence due to requirement of a lower dose of oxytocin for augmentation.

Delivery Progress, Labor Interventions and Perinatal Outcome in Spontaneous Vaginal Delivery of Singleton Pregnancies between Nulliparous and Primiparous Women with One Previous Elective Cesarean Section: A Retrospective Comparative Study

Trial of labor after cesarean (TOLAC) is an alternative to repeated cesarean for women with singleton pregnancy and one previous transverse lower segment cesarean section (LSCS), resulting in most cases being a successful vaginal birth after cesarean section (VBAC). The primary objective of this study was to examine if the progress and the duration of the active first stage and the second stage of labor in nulliparous women with singleton pregnancy, spontaneous start of labor and vaginal birth differ from primiparous women succeeding VBAC after one previous elective LSCS in a country with a low cesarean section and high VBAC rate. Secondary objectives were to compare labor interventions and maternal-neonatal outcomes between the two groups.

METHODS

This is a retrospective comparative study. Data were collected in a four-year period at the departments of Obstetrics and Gynecology at Kristianstad and Ystad hospitals in Sweden. Out of 14,925 deliveries, 106 primipara women with one previous elective LSCS and a spontaneous labor onset in the subsequent singleton pregnancy were identified. Of these women, 94 (88.7%) delivered vaginally and were included in the study (VBAC group). The comparison group included 212 randomly selected nulliparous women that had a normal singleton pregnancy, spontaneous labor onset and delivered vaginally.

RESULTS

The rate of cervical dilation during the active first stage of labor as well as the duration of the second stage did not differ between the two groups. When adjusting for cervical dilation at admission, there was no significant difference between the two groups regarding the duration of the active phase of the first stage of labor. No significant differences were found in maternal-neonatal outcomes between the two groups except for higher birth weight in the VBAC group. The use of epidural analgesia was associated with slower dilation rhythm over the duration of the active phase and second stage of labor, need for labor augmentation, postpartum bleeding and need for transfusion at higher rates, irrespective of parity when epidural was used.

CONCLUSIONS

Our study provides evidence that in women with one previous elective LSCS undergoing TOLAC in the subsequent pregnancy resulting in vaginal birth, the progress and duration of labor are not different from those in nulliparous women when labor is spontaneous and the it is a singleton pregnancy. The use of epidural was associated with prolonged labor, need for labor augmentation and higher postpartum bleeding, irrespective of parity. This information may be useful in patient counseling and labor management in TOLAC.

Labor characteristics and intrapartum interventions in women with vaginal birth after cesarean section

Background

With the development of China’s two-child-policy, vaginal birth after cesarean section (VBAC) has aroused public concern. It is important to understand the labour characteristics and intrapartum management of women attempting VBAC to enhance the rates of successful VBAC. The purpose of our research was to investigate the differences in the characteristics of labor, intervention measures and perinatal outcomes between women who had a VBAC and primiparas or multiparas not undergoing VBAC, providing clinical references of intrapartum management for women who are planning a VBAC.

Material and methods

This observational retrospective study enrolled all women who laboured spontaneously and who had a VBAC (n = 139) at the Second Affiliated Hospital of Wenzhou Medical University in China between 2016 and 2019. They were allocated into VBAC group A (the previous cesarean section was performed before dilation of the cervix) and VBAC group B (the previous cesarean section was performed after dilation of the cervix). The primipara control group included 149 primiparae, and the multipara control group included 155 multiparae with second vaginal birth. Durations of labor, intervention measures and perinatal outcomes were compared among the groups.

Results

The durations of labor, intrapartum interventions and maternal and neonatal outcomes in VBAC group A were similar to those of the VBAC group B. However, all women who had a VBAC and those in VBAC group A had shorter first, second and the total stages of labor than primiparae. All women with VBAC and those in VBAC group B had longer second stage of labor, but shorter third stage of labor than multiparae. Oxytocin, labor analgesia and artificial rupture of membranes were administered less often in women with VBAC than in primiparae, while phloroglucinol was administered more often in women with VBAC than in multiparae. Women who had a VBAC were more likely to receive episiotomy and had higher incidences of postpartum hemorrhage than primipara and multipara women.

Conclusions

Labor characteristics, intrapartum interventions and perinatal outcomes in women who had a VBAC with cervical dilation were similar to those in women who had a VBAC without cervical dilation before the previous cesarean section, but differed significantly from those of multiparae and primiparae who did not undergo VBAC.

Spontaneous labor patterns among women attempting vaginal birth after cesarean delivery

OBJECTIVE

This study evaluated spontaneous labor patterns among women achieving a vaginal birth after cesarean (VBAC), without a previous vaginal delivery in relation to nulliparous women.

METHODS

This historical cohort study included 422 women attempting VBAC and 150 nulliparas. We examined time intervals for each centimeter of cervical dilation and compared labor progression in 321 women who achieved spontaneous VBAC and 147 nulliparous women achieving a spontaneous vaginal delivery. Epidural anesthesia use, delivery mode, cord arterial pH and 5-minute Apgar score were also compared.

FINDINGS

Women in the VBAC group compared to nulliparous women had similar durations of first (4-10 cm: 4:22 (00:54-13:10) h vs. 4:47 (1:10-15:10) h, p = .61), second (1:07 (8:00-3:21), vs. 1:34 (10:00-3:40), p = .124) and third stages of labor (10:00 (2:00-22:00) vs. 08:00 (3:24-22:12), p = .788). When comparing women who had epidural analgesia to those who did not, no differences were found between the groups regarding durations of first and second stages of labor. Interestingly, among parturients without epidural anesthesia only, the VBAC group had shorter second stage compared to the nulliparous (00:19 (0:04-1:59) vs. 00:47 (0:08-2:09), p = .023).

CONCLUSION

Labor patterns among women achieving spontaneous VBAC are similar to those of nulliparous women with spontaneous vaginal deliveries.

Cervical ripening after cesarean section: a prospective dual center study comparing a mechanical osmotic dilator vs. prostaglandin E2

OBJECTIVES

Worldwide, the overall cesarean section is rising. Trial of labor after cesarean (TOLAC) is an overall safe option with an immediate impact on neonatal and maternal short- and long-term health. Since the use of prostaglandins in cervical ripening is associated with an increased risk of uterine rupture, mechanical methods as balloon catheters or osmotic dilators have been suggested for cervical ripening prior to induction of labour. Here we are analyzing and comparing the VBAC rate, as well as maternal and fetal outcome in cervical ripening prior to TOLAC.

METHODS

This prospective dual center study analyses maternal and neonatal outcomes of TOLAC in women with an unfavorable cervix requiring cervical ripening agent. The prospective application of an osmotic dilator (Dilapan-S, n=104) was analysed in comparison to the retrospective application of off-label dinoprostone (n=102).

RESULTS

The overall fetal and neonatal outcome revealed no significant differences in both groups. Patients receiving cervical ripening with the osmotic dilator delivered vaginally/by ventouse in 52% of cases, compared to 53% when using dinoprostone (p=0.603). The interval between application to onset of labor was significantly higher in the osmotic dilator group (37.9 vs.20.7 h, p=<0.001). However, time from onset of labor to delivery was similar in both groups (7.93 vs. 7.44 h, p=0.758). There was one case of uterine rupture in the dinoprostone group.

CONCLUSIONS

Our data shows that the application of the osmotic dilator leads to similar outcomes in VBAC rate and time from onset of labor to delivery as well as safety in both groups compared to off-label use dinoprostone. Cervical ripening using the mechanical dilator is a viable and effective option, without the risk of uterine hyperstimulation.

The continuum of a prolonged labor and a second stage cesarean delivery

OBJECTIVE

To investigate the association of the timing of primary cesarean delivery with the progress of labor and the operative delivery rate at the subsequent successful trial of labor.

METHODS

A retrospective study of women with a primary cesarean and subsequent term cephalic vaginal delivery in two medical centers. Cesarean deliveries were classified as planned, intrapartum first stage or intrapartum second stage. The second stage duration and the operative delivery rate, adjusted to epidural analgesia and oxytocin use, were compared between the groups. χ² and Kruskal-Wallis tests were used for analysis of categorical and continuous variables, respectively.

RESULTS

The study population included 1166 women. The second stage of labor was longer when the previous cesarean delivery occurred during the second stage compared to planned or first stage (1.7 h vs 1.3 h vs 1.3 h, p = 0.005). The proportion of operative deliveries was greater among women with previous cesarean in the second stage of labor (39.6%), compared to planned (26.9%) or first stage (28.8%), p = 0.006.

CONCLUSION

Cesarean delivery at the second stage of labor is associated with a longer second stage and an increased operative delivery rate at the subsequent vaginal birth. Our findings attest to the delicate passenger-passage relations that can exist in some parent-couples.

Safety and feasibility of trial of vaginal labor after cesarean section: A retrospective study

By observing and analyzing the success rate of Tai'an City central hospital TOLAC and VBNC and various indicators after delivery, we make sure whether TOLAC is safe and feasible to be promoted in Tai'an area.Between January and December 2017, data of 144 cases undergoing TOLAC, 152 cases undergoing VBNC, 152 cases undergoing RCS and 142 case undergoing PCS in Tai'an City Central Hospital were retrospectively analyzed. The success rate of vaginal delivery, labor time, 24 hours postpartum hemorrhage, hospital stay, Apgar score of newborns and puerperal morbidity were observed.Primary study outcomes: The success rates of the TOLAC and VBNC groups were 93.06% and 93.42%, respectively, where the difference was not statistically significant (P = .901). Secondary study outcomes: There were no significant differences in labor time (P = .0249), amount of 24 hours postpartum hemorrhage (P = .206), Apgar score of newborns (P = .582), hospital stay (P = .194) and puerperal morbidity (P = .942) between the VBAC group and VBNC group. There were statistically significant differences in amount of 24 hours postpartum hemorrhage (P < .001), hospital stay (P < .001) and puerperal morbidity (P = .018), but no difference in Apgar score of newborns (P = .228) between the VBAC group and RCS group. There were significant differences in operation time (P = .011), amount of 24 hours hemorrhage (P = .001), hospital stay (P = .001) and puerperal morbidity (P = .041), but no significant difference in Apgar score of newborns (P = .300) between the RCS and PCS groups.The TOLAC is as safe and feasible as VBNC, and more favorable to the safety of mother and fetus than RCS in Tai'an area.

Duration of first vaginal birth following cesarean: Is stage of labor at previous cesarean a factor?

OBJECTIVE

Parturients in second delivery undergoing vaginal birth after cesarean (VBAC) are divided to those who had their cesarean delivery (CD) while in labor as opposed to those who had an elective CD. We aimed to study if the stage of labor that was present during the primary CD is associated with the duration of subsequent spontaneous VBAC.

METHODS

A retrospective study (2006-2014). Multiparas in second delivery with a history of a CD (P2-VBAC) were sub-grouped based on stage of labor at which the CD was performed in the first delivery; elective, latent, first or second stage of labor, Duration of labor was compared between P2-VBAC (as one group and further as the sub-groups) to primiparas (P1), multiparas in second (P2) and third (P3) vaginal delivery (VD). A Cox regression analysis was performed including maternal age, preterm-delivery, regional anesthesia, oxytocin augmentation, birthweight and neonatal gender.

RESULTS

A total of 58,028 parturients were included in the study. Mean duration of labor was significantly longer in parturients with a first VD (P1 and P2-VBAC) compared to repeat VD (P2 and P3), 6.0 versus 2.5 h, respectively, (P < 0.001). Analyzing duration of labor by the sub-groups of P2-VBAC revealed that spontaneous VD following a second-stage CD was associated with shorter duration of labor when compared with spontaneous VD following elective, latent and active first stage CD 4.2 versus 6.3, 7.0, 6.9 h respectively, p<0.001.

CONCLUSION

Second stage CD shortens duration of the following VBAC compared to those who underwent cesarean in earlier stages of labor.

Prediction of vaginal birth after cesarean deliveries using machine learning

BACKGROUND

Efforts to reduce cesarean delivery rates to 12-15% have been undertaken worldwide. Special focus has been directed towards parturients who undergo a trial of labor after cesarean delivery to reduce the burden of repeated cesarean deliveries. Complication rates are lowest when a vaginal birth is achieved and highest when an unplanned cesarean delivery is performed, which emphasizes the need to assess, in advance, the likelihood of a successful vaginal birth after cesarean delivery. Vaginal birth after cesarean delivery calculators have been developed in different populations; however, some limitations to their implementation into clinical practice have been described. Machine-learning methods enable investigation of large-scale datasets with input combinations that traditional statistical analysis tools have difficulty processing.

OBJECTIVE

The aim of this study was to evaluate the feasibility of using machine-learning methods to predict a successful vaginal birth after cesarean delivery.

STUDY DESIGN

The electronic medical records of singleton, term labors during a 12-year period in a tertiary referral center were analyzed. With the use of gradient boosting, models that incorporated multiple maternal and fetal features were created to predict successful vaginal birth in parturients who undergo a trial of labor after cesarean delivery. One model was created to provide a personalized risk score for vaginal birth after cesarean delivery with the use of features that are available as early as the first antenatal visit; a second model was created that reassesses this score after features are added that are available only in proximity to delivery.

RESULTS

A cohort of 9888 parturients with 1 previous cesarean delivery was identified, of which 75.6% of parturients (n=7473) attempted a trial of labor, with a success rate of 88%. A machine-learning-based model to predict when vaginal delivery would be successful was developed. When features that are available at the first antenatal visit are used, the model showed a receiver operating characteristic curve with area under the curve of 0.745 (95% confidence interval, 0.728-0.762) that increased to 0.793 (95% confidence interval, 0.778-0.808) when features that are available in proximity to the delivery process were added. Additionally, for the later model, a risk stratification tool was built to allocate parturients into low-, medium-, and high-risk groups for failed trial of labor after cesarean delivery. The low- and medium-risk groups (42.4% and 25.6% of parturients, respectively) showed a success rate of 97.3% and 90.9%, respectively. The high-risk group (32.1%) had a vaginal delivery success rate of 73.3%. Application of the model to a cohort of parturients who elected a repeat cesarean delivery (n=2145) demonstrated that 31% of these parturients would have been allocated to the low- and medium-risk groups had a trial of labor been attempted.

CONCLUSION

Trial of labor after cesarean delivery is safe for most parturients. Success rates are high, even in a population with high rates of trial of labor after cesarean delivery. Application of a machine-learning algorithm to assign a personalized risk score for a successful vaginal birth after cesarean delivery may help in decision-making and contribute to a reduction in cesarean delivery rates. Parturient allocation to risk groups may help delivery process management.

Reasons for previous Cesarean deliveries impact a woman's independent decision of delivery mode and the success of trial of labor after Cesarean

Background

Cesarean delivery rates are increasing globally with almost half of them occurring due to a previous Cesarean delivery. A trial of labor after Cesarean (TOLAC) is considered a safe procedure, but most eligible women instead undergo Cesarean before 39 weeks of gestation. Lack of education about TOLAC is often associated with increased repeat Cesarean. To reveal the safety and feasibility of TOLAC, we conducted this observational, prospective study with women’s independent decisions. We aimed to clarify the relationship between their chosen mode of delivery and the reason for their previous Cesarean. Additionally, we have tried to identify maternal and obstetric factors associated with failed TOLAC to improve its success rate.

Methods

This was a prospective, observational study of 1086 pregnant women with at least one previous Cesarean delivery. Of these, 735 women met our TOLAC criteria (Table 1), and then, could choose TOLAC or repeat Cesarean after receiving detailed explanations regarding the risks and benefits of both procedures. The primary outcomes were the number of successful TOLAC procedures and 5-min Apgar scores < 7 for the trial of labor after Cesarean group and elective Cesarean group. We collected the maternal and neonatal data including the reasons of previous Cesarean.

Results

In total, 64.1% of women chose TOLAC. The success rate was 91.3%. The uterine rupture rate was 0.6%. There were no significant differences in the rate of Apgar scores at 5 min < 7 between both groups. Histories of experience of labor in previous Cesarean delivery were observed in 30 and 50% of women who chose TOLAC and repeat Cesarean, respectively (p < 0.05). Factors related to failed TOLAC included ≥40 weeks of gestation (odds: 5.47, 95% CI: 2.55–11.70) and prelabor rupture of membranes (PROM) (odds: 4.47, 95% CI: 2.07–9.63).

Conclusions

TOLAC is a favorable delivery option for both mothers and neonates when women meet criteria and choose after receiving detailed explanations. Women who experience PROM or ≥ 40 weeks of gestation, their modes of delivery should be reconsulted.

ACOG Practice Bulletin No. 205: Vaginal Birth After Cesarean Delivery

Trial of labor after cesarean delivery (TOLAC) refers to a planned attempt to deliver vaginally by a woman who has had a previous cesarean delivery, regardless of the outcome. This method provides women who desire a vaginal delivery the possibility of achieving that goal-a vaginal birth after cesarean delivery (VBAC). In addition to fulfilling a patient's preference for vaginal delivery, at an individual level, VBAC is associated with decreased maternal morbidity and a decreased risk of complications in future pregnancies as well as a decrease in the overall cesarean delivery rate at the population level (). However, although TOLAC is appropriate for many women, several factors increase the likelihood of a failed trial of labor, which in turn is associated with increased maternal and perinatal morbidity when compared with a successful trial of labor (ie, VBAC) and elective repeat cesarean delivery (). Therefore, assessing the likelihood of VBAC as well as the individual risks is important when determining who is an appropriate candidate for TOLAC. Thus, the purpose of this document is to review the risks and benefits of TOLAC in various clinical situations and to provide practical guidelines for counseling and management of patients who will attempt to give birth vaginally after a previous cesarean delivery.

Intrapartum interventions that affect maternal and neonatal outcomes for vaginal birth after cesarean section

Objective

To investigate maternal and neonatal outcomes after different intrapartum interventions for vaginal birth after cesarean section (VBAC) in mainland China.

Methods

A retrospective study was performed on 143 VBAC cases from Beijing Obstetrics and Gynecology Hospital between January 2015 and November 2016. These cases were divided into two groups on the basis of different intrapartum interventions. Maternal and neonatal outcomes were compared.

Results

The durations of the first stage and total labor after oxytocin were significantly longer than those before oxytocin use. The proportion of operative vaginal delivery with oxytocin was significantly higher than that without oxytocin (43.9% vs. 11.8%). The times of the first stage, second stage, and total labor with analgesia were significantly longer than those without analgesia (548.4±198.1 vs. 341.8±233.0 minutes, 52.0±38.9 vs. 36.0± 29.1 minutes, and 606.3±212.1 vs. 387.3±233.0 minutes, respectively). Postpartum hemorrhage and operative vaginal delivery occurred significantly more frequently in women with epidural analgesia than in those without epidural analgesia (29.7% vs. 12.3 and 35.1% vs. 16.0%, respectively).

Conclusions

Induction can increase the rate of operative vaginal delivery in VBAC. Oxytocin and epidural analgesia may increase the risk of operative vaginal delivery, and may be associated with a prolonged duration of labor.

Duration of labor and maternal and neonatal morbidity

BACKGROUND

Labor dystocia has been identified as a contributor to the rising cesarean delivery rate in the United States. Allowing more time for vaginal delivery, while being cognizant of maternal and neonatal outcomes, has been identified as a possible strategy to lower cesarean delivery rates.

OBJECTIVE

This study aimed to characterize the relationship between the duration of active phase and second-stage labor and maternal and neonatal morbidity.

STUDY DESIGN

We present a secondary analysis of the Consortium on Safe Labor project. From labors of 66,940 nonanomalous nulliparous term singleton vertex gestations, we excluded labors for which active phase (≥6 cm dilation) or second stage durations could not be calculated and from sites that did not report determinants of morbidity. For each duration of active phase or second stage labor (grouped in 1-hour increments), the adjusted maternal and neonatal composite morbidity was estimated by and compared with the morbidity associated with a duration <1 hour total and a duration of 1 hour shorter.

RESULTS

After exclusions, 48,144 deliveries remained. In adjusted models, compared with labor durations <1 hour total, maternal composite morbidity was significantly higher across active phase and second stage durations (both P<.001); neonatal composite morbidity was higher across the second stage (P<.001), but not active phase (P=.07) duration. These relationships appear linear with no apparent inflection point, and morbidity increases more rapidly. When compared with labor durations 1 hour shorter, significant differences persisted in maternal and neonatal composite morbidity in second stage labor only through 4 and 3 hours, respectively.

CONCLUSION

Maternal and neonatal composite morbidity is greater with longer durations of active and second stage labor; however, no clear cutoff point was determined to suggest truncation of either stage of labor for reasons of morbidity. In addition, incrementally higher morbidities that were noted vs duration <1 hour total were obscured when comparison was made with labors 1 hour shorter, which suggests that focusing on short differences in duration of labor may mask important underlying trends.

Inter-institutional variations in oxytocin augmentation during labour in German university hospitals: a national survey

BACKGROUND

There are several international guidelines on oxytocin regimens for induction and augmentation of labour, but no agreement on a standardised regimen in Germany. This study collated and reviewed the oxytocin regimens used for labour augmentation in university hospitals, with the long-term aim of contributing to the development of a national clinical guideline.

METHODS

Germany has 34 university hospital compounds, representing 39 maternity units. In this observational study we asked units to provide standard operational procedures on oxytocin augmentation during labour or provide the details in a structured survey. Data were collected on the dosage of oxytocin, type and volume of solutions used, indications and contraindications for use and discontinuation, case-specific administration, and on who developed the procedures. Findings were analysed descriptively.

RESULTS

A total of 35 (90%) units participated in this study. Standard operating procedures were available in 24 units (69%), seven units (20%) did not have procedures and information was missing from four units (11%). Midwives participated in the development of standard operating procedures in 15 units (43%). Infusions were most commonly prepared using six units of oxytocin in 500 ml 0.9% normal saline solution (12 mU/ml). The infusions were started at 120 mU/hour and increased by 120 mU/hour at 20-min intervals up to a maximum dosage of 1200 mU/hour. The most common indication for use was delayed progress in labour. Infusions were stopped when uterine contractions became hypertonic and/or the fetal heart rate showed signs of distress. Most of the practices described aligned with international guidance. All units used reduced oxytocin dosages for women with a history of previous caesareans section, as recommended in the international guidelines, and restrictive use was advised in multiparous women. The main difference between units related to combined use of amniotomy and oxytocin, recommended by three guidelines but used in only four maternity units (11%).

CONCLUSIONS

While there was considerable variation in the oxytocin augmentation procedures, most but not all practices used in these 35 German maternity units were comparable. Establishing a national guideline on the criteria for and administration of oxytocin for augmentation of labour would eliminate the observed differences and minimise risk of administration and medication error.

Timing of cesarean and its impact on labor duration and genital tract trauma at the first subsequent vaginal birth: a retrospective cohort study

Background

The objectives of this study were to explore the course of labor and the risk of obstetric anal sphincter injury at the first vaginal birth after cesarean section (fVBAC) in comparison to primiparous vaginal birth (PVB) in women without epidural analgesia and to assess if laboring before the previous cesarean affected these outcomes.

Methods

All fVBACs without epidural analgesia and the subsequent PVBs (controls) between 2012 and 2016 were included in this retrospective cohort study. Data were collected from health records and included maternal demographics, gestational age, and labor details (duration of 1st and 2nd stages, labor induction or augmentation, birthweight, operative vaginal birth, estimated blood loss, extent of childbirth trauma) in both groups as well as cervical dilation at the time of previous cesarean in the fVBAC group. Wilcoxon and Chi-square tests were used for data analyses.

Results

The study comprised 510 women; 255 fVBACs and 255 controls. The majority of fVBACs were after a pre-labor cesarean section – 177 (69.4%). There was a statistically significant difference in the recorded duration of first stage between the fVBACs and controls (289 vs. 347 min respectively, p < .001). Women were less likely to have an intact perineum in the fVBAC group (29.8 vs. 43.1%, p < 0.01), however, there was no statistically significant difference in anal sphincter injury rates between both groups (2.3 vs. 1.9%, p = 0.76). The groups differed in rates of cervical tears requiring suturing (21.2 vs. 12.9%, p = 0.01). On further subgroup analysis, the duration of first stage of labor was shorter in women who previously had a caesarean section late in labor (≥ 8 cm cervical dilatation) compared to a pre-labor cesarean section, however, there were no differences in other outcomes.

Conclusion

Compared to primiparous women having a vaginal birth, women having their first vaginal birth after a cesarean section have a shorter 1st stage of labor (particularly if the cesarean was performed in advanced labor), a higher risk of sustaining cervical lacerations and perineal trauma. However, there was no difference in the risk of sustaining obstetric anal sphincter injuries between the study groups.

Electronic supplementary material

The online version of this article (10.1186/s12884-019-2359-7) contains supplementary material, which is available to authorized users.

Vaginal Birth After Previous Cesarean Birth: A Comparison of 3 National Guidelines

Importance

Vaginal birth after previous cesarean birth (VBAC) is a reasonable option for many women with previous cesarean delivery.

Objective

The aim of this study was to summarize evidence and compare recommendations from national guidelines regarding VBAC.

Evidence Acquisition

A descriptive review of 3 national guidelines on VBAC was conducted: Royal College of Obstetricians and Gynaecologists on "Birth After Previous Caesarean Birth," American College of Obstetricians and Gynecologists on "Vaginal Birth After Cesarean Delivery," and Society of Obstetricians and Gynaecologists of Canada on "Guidelines for Vaginal Birth After Previous Caesarean Birth." These guidelines were summarized and compared in terms of the recommended antenatal and intrapartum care of women. Recommendations and strength of evidence were also reviewed based on method of reporting.

Results

The variations mentioned on the different guidelines reflect the heterogeneity of the published data on the management of VBAC during the antenatal and intrapartum care.

Conclusions

Evidence-based medicine could support the conception of international recommendations for VBAC, which may improve both safety and efficacy of this procedure.

Labor progression of women attempting vaginal birth after previous cesarean delivery with or without epidural analgesia

PURPOSE

Normal labor curves have not been assessed for women undergoing a trial of labor after cesarean delivery (TOLAC). This study examined labor patterns during TOLAC in relation to epidural analgesia use.

METHODS

Retrospective cohort study of deliveries of women undergoing TOLAC at a single, academic, tertiary medical center. Length of first, second and third stages of labor was compared between 424 women undergoing TOLAC in the current labor with no previous vaginal delivery (VD) and 357 women with at least one previous VD and current TOLAC.

RESULTS

Women in the TOLAC only group had significantly longer labors compared to women in the previous VD and TOLAC group. In both groups, women who underwent epidural analgesia had longer first and second stages of labor. In the TOLAC only group, more women who had epidural analgesia tended to deliver vaginally as compared to those who did not (P = 0.09). For women who delivered vaginally, the 95th percentile for the second stage duration with epidural was 3.40 h in the TOLAC only group and 2.3 h in the previous VD and TOLAC group. The 95th percentile for the second stage duration without epidural was 1.4 h in the TOLAC only group and 0.9 h in the previous VD and TOLAC group.

CONCLUSIONS

Operative intervention (instrumental delivery/cesarean delivery (CD)) might be considered for women attempting TOLAC after a 2-h duration of second stage without epidural and 3-h duration with epidural, with an hour less for women who also had previous VD.

Labor Onset, Oxytocin Use, and Epidural Anesthesia for Vaginal Birth after Cesarean Section and Associated Effects on Maternal and Neonatal Outcomes in a Tertiary Hospital in China: A Retrospective Study

Background

In the mainland of China, the trial of labor after cesarean section is still a relatively new technique. In this study, we aimed to investigate the effects of labor onset, oxytocin use, and epidural anesthesia on maternal and neonatal outcomes for vaginal birth after cesarean section (VBAC) in a tertiary hospital in China.

Methods

This was a retrospective study carried out on 212 VBAC cases between January 2015 and June 2017 in Beijing Obstetrics and Gynecology Hospital, Capital Medical University. Relevant data were acquired on a form, including maternal age, gravidity and parity, body mass index before pregnancy, weight gain during pregnancy, type of labor onset, gestational age, the use of oxytocin and epidural anesthesia, birth mode, the duration of labor, and neonatal weight. The factors affecting maternal and neonatal outcomes for cases involving VBAC, especially with regards to postpartum hemorrhage (PPH) and fetal distress, were evaluated by univariate analysis and multivariable logistic regression.

Results

Data showed that 36 women (17.0%) had postpartum hemorrhage (PPH) and 51 cases (24.1%) featured fetal distress. Normal delivery took place for 163 infants (76.9%) while 49 infants (23.1%) underwent operative vaginal deliveries with forceps. There were 178 cases (84.0%) of spontaneous labor and 34 cases (16.0%) required induction. Oxytocin was used in 54 cases (25.5%) to strengthen uterine contraction, and 65 cases (30.7%) received epidural anesthesia. The rate of normal delivery in cases involving PPH was significantly lower than those without PPH (61.1% vs. 80.1%; χ² = 6.07, P = 0.01). Multivariate logistic analysis showed that the intrapartum administration of oxytocin (odds ratio [OR] = 2.47; 95% confidence interval [CI] = 1.07-5.74; P = 0.04) and birth mode (OR = 0.40; 95% CI = 0.18-0.87; P = 0.02) was significantly associated with PPH in VBAC cases. Operative vaginal delivery occurred more frequently in the group with fetal distress than the group without (49.0% vs. 14.9%, χ² = 25.36, P = 0.00). Multivariate logistic analysis also revealed that the duration of total labor (OR = 1.01; 95% CI = 1.00-1.03; P = 0.04) and the gestational week of delivery (OR = 1.08; 95% CI = 1.05-1.11; P = 0.00) were significantly associated with fetal distress in VBAC.

Conclusions

The administration of oxytocin during labor and birth was identified as a protective factor for PPH in VBAC while birth mode was identified as a risk factor. Finally, the duration of total labor and the gestational week of delivery were identified as risk factors for fetal distress in cases of VBAC. This information might help obstetricians provide appropriate interventions during labor and birth for VBAC.

Cervical ripening agents in the second trimester of pregnancy in women with a scarred uterus: a systematic review and metaanalysis of observational studies

OBJECTIVE

The aim of this systematic review and metaanalysis was to determine the efficacy and safety of cervical ripening agents in the second trimester of pregnancy in patients with previous cesarean delivery.

STUDY DESIGN

Data sources were PubMed, EMBASE, CINAHL, LILACS, Google Scholar, and clinicaltrials.gov (1983 through 2015). Eligibility criteria were cohort or cross-sectional studies that reported on efficacy and safety of cervical ripening agents in patients with previous cesarean delivery. Efficacy was determined based on the proportion of patients achieving vaginal delivery and vaginal delivery within 24 hours following administration of a cervical ripening agent. Safety was assessed by the risk of uterine rupture and complications such as retained placental products, blood transfusion requirement, and endometritis, when available, as secondary outcomes. Of the 176 studies identified, 38 met the inclusion criteria. Of these, 17 studies were descriptive and 21 studies compared the efficacy and safety of cervical ripening agents between patients with previous cesarean and those with no previous cesarean. From included studies, we abstracted data on cervical ripening agents and estimated the pooled risk differences and risk ratios with 95% confidence intervals. To account for between-study heterogeneity, we estimated risk ratios based on underlying random effects analyses. Publication bias was assessed via funnel plots and across-study heterogeneity was assessed based on the I(2) measure.

RESULTS

The most commonly used agent was PGE1. In descriptive studies, PGE1 was associated with a vaginal delivery rate of 96.8%, of which 76.3% occurred within 24 hours, uterine rupture in 0.8%, retained placenta in 10.8%, and endometritis in 3.9% in patients with ≥1 cesarean. In comparative studies, the use of PGE1, PGE2, and mechanical methods (laminaria and dilation and curettage) were equally efficacious in achieving vaginal delivery between patients with and without prior cesarean (risk ratio, 0.99, and 95% confidence interval, 0.98-1.00; risk ratio, 1.00, and 95% confidence interval, 0.98-1.02; and risk ratio, 1.00, and 95% confidence interval, 0.98-1.01; respectively). In patients with history of ≥1 cesarean the use of PGE1 was associated with higher risk of uterine rupture (risk ratio, 6.57; 95% confidence interval, 2.21-19.52) and retained placenta (risk ratio, 1.21; 95% confidence interval, 1.03-1.43) compared to women without a prior cesarean. However, the risk of uterine rupture among women with history of only 1 cesarean (0.47%) was not statistically significant (risk ratio, 2.36; 95% confidence interval, 0.39-14.32), whereas among those with history of ≥2 cesareans (2.5%) was increased as compared to those with no previous cesarean (0.08%) (risk ratio, 17.55; 95% confidence interval, 3.00-102.8). Funnel plots did not demonstrate any clear evidence of publication bias. Across-study heterogeneity ranged from 0-81%.

CONCLUSION

This systematic review and metaanalysis provides evidence that PGE1, PGE2, and mechanical methods are efficacious for achieving vaginal delivery in women with previous cesarean delivery. The use of prostaglandin PGE1 in the second trimester was not associated with significantly increased risk for uterine rupture among women with only 1 cesarean; however, this risk was substantially increased among women with ≥2 cesareans although the absolute risk appeared to be relatively small.

Labour duration and timing of interventions in women planning vaginal birth after caesarean section

OBJECTIVE

understanding the labour characteristics of women attempting vaginal birth after caesarean (VBAC) may suggest how to improve intrapartum management and may enhance success rates. Promoting VBAC is a relevant factor in decreasing overall caesarean section (c-section) rates. However, the labour processes of women attempting VBAC are not well investigated. The aim of this paper is to compare multiparae planning a first VBAC (pVBAC) with primiparae and with multiparae planning a second vaginal birth, all starting to give birth vaginally, with regard to (a) perinatal characteristics, (b) the timing of intrapartal spontaneous rupture of membranes (SROM) and of interventions, and (c) labour duration, with respect to the first and second stages.

SETTING

cohort study of women planning vaginal birth in 47 obstetric units in Lower Saxony, Germany.

PARTICIPANTS

1897 primiparae, 211 multiparae with one previous c-section and 1149 multiparae with one previous vaginal birth.

MEASUREMENTS

secondary analysis of data from an existing cohort study. Kaplan-Meier estimates, log rank test, Wilcoxon test and shared frailty Cox regression models including time-varying covariates were used to compare the timing of interventions and labour duration between the subsamples. Analyses were done with the statistics programme Stata 13.

FINDINGS

perinatal and labour characteristics of multiparae with pVBAC mainly resembled those of primiparae and differed from those of multiparae planning a second vaginal birth. However, compared to primiparae, multiparae with pVBAC received oxytocin less often (48.82 versus 56.95%, p=0.024) and gave birth vaginally significantly less often (69.19 versus 83.40%, p<0.001). The timing of intrapartal SROM (2.67 versus 3.42 hours, p=0.112) and of interventions (amniotomy: 5.50 versus 5.83 hours, p=0.198; oxytocin: 5.75 versus 6.00 hours, p=0.596; epidural: 4.00 versus 4.67 hours, p=0.416; opioids: 3.83 versus 3.78, p=0.851) was similar to that in primiparae although timings of all interventions but not of SROM differed significantly from that in multiparae with second vaginal birth (SROM: 2.67 versus 2.67 hours, p=0.481; amniotomy: 5.50 versus 3.93 hours, p<0.001; oxytocin: 5.75 versus 4.25 hours, p<0.001; epidural: 4.00 versus 3.50 hours, p=0.009; 3.83 versus. 2.75 hours, p=0.026). Overall and first-stage labour duration were comparable to primiparae (overall labour duration: 8.83 versus 8.57 hours, HR=0.998, 95% CI=0.830-1.201, p=0.987; first stage: 7.42 versus 7.00 hours, HR=0.916, 95% CI=0.774-1.083, p=0.303) but significantly longer than in other multiparae (overall labour duration: 8.83 versus 4.63 hours, HR=0.319, 95% CI=0.265-0.385, p<0.001; first stage: 7.42 versus 4.25 hours, HR=0.402, 95% CI=0.339-0.478, p<0.001). However, the second stage of labour was significantly shorter in multiparae with pVBAC than in primiparae (0.55 versus 0.77 hours, HR=1.341, 95% CI=1.049-1.714, p=0.019), but longer than in multiparae with second vaginal birth (0.55 versus 0.22 hours, HR=0.334, 95% CI=0.262-0.426, p<0.001).

KEY CONCLUSION

labour patterns of multiparous women planning a VBAC differ from those of primiparae and other multiparous women. Multiparae with pVBAC should be considered as a distinct group of parturients.

IMPLICATION FOR PRACTICE

expectations regarding labour progression for multiparae with first pVBAC should be similar to those for primiparae. However, the chance that the second stage of labour might be shorter than in primiparae is relevant and motivating information for pregnant women with a previous c-section in deciding the planned mode of birth.