Normal First Stage of Labor in Women Undergoing Trial of Labor After Cesarean Delivery:

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.

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.

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.

Association of abnormal first stage of labor duration and maternal and neonatal morbidity

BACKGROUND

Contemporary guidelines for labor management do not characterize abnormal labor on the basis of maternal and/or neonatal morbidity.

OBJECTIVE

In this study, we aimed to evaluate the association of abnormal duration of the first stage of term labor and the risk of maternal and neonatal morbidity.

STUDY DESIGN

We conducted a retrospective analysis of prospectively collected data of all consecutive women admitted for delivery at a single center at ≥37 weeks and 0 to 7 days of gestation with singleton, nonanomalous, vertex infants from 2010 to 2015, who reached 10 cm cervical dilation. Multivariable logistic regression compared odds ratios for maternal and neonatal outcomes among women above and below the 90th, 95th, and 97th percentiles for first stage of labor duration. Receiver operating characteristic curves estimated the association between first stage of labor duration and maternal morbidity. Maternal morbidity was a composite of maternal fever, hemorrhage, transfusion, or endomyometritis; prolonged second stage of labor duration; and third- or fourth-degree perineal laceration. Neonatal morbidity was a composite of hypothermic therapy, need for mechanical ventilation, respiratory distress syndrome, meconium aspiration syndrome, birth injury or trauma, and neonatal seizure or sepsis.

RESULTS

Of 6823 women included in this study, 682 were anticipated to have first stage of labor duration above the 90th percentile cutoff point, which was associated with an increased risk of composite maternal morbidity, maternal fever, postpartum transfusion, prolonged second stage of labor duration, third- or fourth-degree perineal laceration, and cesarean or operative vaginal delivery (P≤.02) and an increased risk of composite neonatal morbidity, respiratory distress syndrome, need for mechanical ventilation, and neonatal sepsis (P≤.03). Composite maternal morbidity was 2.2 (95% confidence interval, 1.8-2.7), 1.9 (95% confidence interval, 1.4-2.4), and 1.8 (95% confidence interval, 1.3-2.5) times more likely to occur among women above the 90th, 95th, and 97th percentile, respectively, for first stage of labor duration from 4 to 10 cm. Composite neonatal morbidity was 2.6 (95% confidence interval, 2.1-3.2), 2.2 (95% confidence interval, 1.7-2.9), and 1.9 (95% confidence interval, 1.3-2.8) times more likely to occur among infants delivered by women above the 90th, 95th, and 97th percentiles for first stage of labor duration from 4 to 10 cm. Receiver operating characteristic curves among all women from 4 to 10 cm and 6 to 10 cm, including when stratified by parity and type of labor onset, had an area under the curve of 0.51 to 0.62 and 0.53 to 0.71 for maternal and neonatal morbidity, respectively. Thus, duration of labor has moderate predictive ability, at best, for composite maternal or neonatal morbidity. No curve demonstrated a clear point at which adverse maternal or neonatal outcomes increased that could be used to define abnormal labor.

CONCLUSION

The benefit of expectantly managing a prolonged first stage of labor with duration above the 90th percentile in anticipation of vaginal delivery must be weighed against the increased risk of composite maternal and neonatal morbidity. Risks associated with performing cesarean delivery as an alternative management for women with prolonged first stage of labor duration must also be considered.

The determinants of obstetricians' willingness to undertake delivery by vaginal birth after cesarean section in Taiwan

Background

Babies are sometimes delivered by cesarean section (CS) to women eligible for trial of labor after a cesarean (TOLAC) due to a fear of complications during the delivery process. This view is especially widespread in Taiwan, as evidenced by the extremely low rate (<5%) of vaginal birth after cesarean section (VBAC). To improve the safety and quality of childbirth and the obstetrical practice environment, this study aimed to identify ways to contain the ever-increasing rate of CS by investigating the determinants for TOLAC from the viewpoint of obstetricians.

Methods

A specially designed questionnaire was employed that incorporated the perceived risk of VBAC, institutional managerial attitude, and obstetricians' personal characteristics. Face-to-face surveys were conducted with obstetricians from across Taiwan. Regression analysis was used as appropriate.

Results

Among the 231 recruited obstetricians, 86.7% were willing to undertake VBAC, but only 71.4% had actually done so. Obstetricians with a more risk-tolerant personality were more likely to undertake VBAC. Institutional characteristics, such as the time it takes to transfer a woman from the delivery table to the operating table (table to table) and the general facilities of the hospital to handle delivery complications resulting from VBAC were also key determinants for attempting VBAC.

Conclusion

In Taiwan, a country with a low birthrate, obstetricians need to be risk-tolerant to undertake VBAC. This phenomenon is probably due to underinvestment in facilities for vaginal delivery and thus a general perception that VBAC is risky. The study's results will potentially help medical institutions to adopt appropriate guidelines and build incentive structures to achieve a higher VBAC rate.

Reassessing the Duration of the Second Stage of Labor in Relation to Maternal and Neonatal Morbidity

OBJECTIVE

To assess the morbidity associated with continuing the second-stage duration of labor, weighing the probability of spontaneous vaginal birth without morbidity compared with birth with serious maternal or neonatal complications.

METHODS

In a retrospective cohort, we analyzed singleton, vertex births at 36 weeks of gestation or greater without prior cesarean delivery (n=43,810 nulliparous and 59,605 multiparous women). We calculated rates of spontaneous vaginal birth and composite serious maternal or neonatal complications. Results were stratified by parity (nulliparous or multiparous) and epidural status (yes or no). Competing risks models were created for 1) spontaneous vaginal birth with no morbidity, 2) birth with maternal or neonatal morbidity, and 3) no spontaneous vaginal birth and no morbidity, and our main interest was in comparing number 1 against number 2.

RESULTS

Rates of spontaneous vaginal birth without morbidity were slightly higher after the first half hour (greater than 0.5-1.0 hours) for nulliparous women, after which rates decreased with increasing second-stage duration. For multiparous women, rates of spontaneous vaginal birth without morbidity decreased with increasing second-stage duration. For illustration, for a nulliparous woman with an epidural at 3.0 hours of the second stage of labor who extended by another 1.0 hour, her likelihood of delivering by spontaneous vaginal birth was 31.4% compared with her likelihood of birth with any serious complication in the subsequent hour, which was 7.6%. The percentage of cesarean deliveries for nonreassuring fetal heart rate tracing were higher for women without compared with women with an epidural.

CONCLUSION

Rates of spontaneous vaginal birth without serious morbidity steadily decreased for increasing second-stage duration except for the first half hour for nulliparous women. We did not observe an inflection point at a particular hour mark for either spontaneous vaginal delivery without morbidity or births with morbidity. Our findings will assist in decision-making for extending second-stage duration.

Diagnosing onset of labor: a systematic review of definitions in the research literature

BACKGROUND

The diagnosis of labor onset has been described as one of the most important judgments in maternity care. There is compelling evidence that the duration of both latent and active phase labor are clinically important and require consistent approaches to measurement. In order to measure the duration of labor phases systematically, we need standard definitions of their onset. We reviewed the literature to examine definitions of labor onset and the evidentiary basis provided for these definitions.

METHODS

Five electronic databases were searched using predefined search terms. We included English, French and German language studies published between January 1978 and March 2014 defining the onset of latent labor and/or active labor in a population of healthy women with term births. Studies focusing exclusively on induced labor were excluded.

RESULTS

We included 62 studies. Four 'types' of labor onset were defined: latent phase, active phase, first stage and unspecified. Labor onset was most commonly defined through the presence of regular painful contractions (71% of studies) and/or some measure of cervical dilatation (68% of studies). However, there was considerable discrepancy about what constituted onset of labor even within 'type' of labor onset. The majority of studies did not provide evidentiary support for their choice of definition of labor onset.

CONCLUSIONS

There is little consensus regarding definitions of labor onset in the research literature. In order to avoid misdiagnosis of the onset of labor and identify departures from normal labor trajectories, a consistent and measurable definition of labor onset for each phase and stage is essential. In choosing standard definitions, the consequences of their use on rates of maternal and fetal morbidity must also be examined.

Second stage of labor

Current American College of Obstetricians and Gynecologists' definition of prolonged second stage diagnoses 10% to 14% of nulliparous and 3% to 3.5% of multiparous women as having a prolonged second stage. The progression of labor in modern obstetrics may have deviated from the current labor norms established in the 1950s, likely due to differences in obstetric population characteristics and variation in clinical practice. Optimal management of the second stage in women with and without epidural remains debatable. Although prolonged second stage is associated with increased risk of maternal morbidity, conflicting data exist regarding the duration of second stage and associated neonatal morbidity and mortality.

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.

Progress of induced labor in trial of labor after cesarean delivery

OBJECTIVE

The purpose of this study was to compare the first stage of labor progress in women who undergo an induction of labor after cesarean delivery with women who have spontaneous labor after cesarean delivery.

STUDY DESIGN

We conducted a retrospective cohort study of consecutive women who had been admitted for delivery with a vertex-presenting fetus who achieved vaginal delivery after cesarean delivery. We compared women who underwent an induction of labor after cesarean delivery with women with spontaneous labor after cesarean delivery. Labor curves were constructed with a repeated-measures analysis; interval-censored regression was used to estimate the median time spent to dilate 1 cm, stratified by induction status, and adjusted by obesity, macrosomia, epidural, and previous vaginal delivery.

RESULTS

Of 473 laboring women with a previous cesarean delivery, 234 women (49%) were induced. After adjustment for obesity, macrosomia, epidural, and previous vaginal delivery, women who underwent an induction had significantly longer labors than those women who experienced spontaneous labor. The median time to dilate from 4-10 cm took 5.6 hours (95% confidence interval, 1.8-18.0 hours) in the induction group and 3.2 hours (95% confidence interval, 1.0-10.3 hours) in the spontaneous labor group (P < .01). The time to progress 1 cm in dilation from 3-7 cm was different; however, after 7 cm, the time to progress 1 cm was not statistically different.

CONCLUSION

Women who undergo an induction of labor after cesarean delivery have a longer latent labor phase, but a similar active phase than those women who experience spontaneous labor. When making the diagnosis of labor dystocia for women who undergo an induction of labor after cesarean delivery, clinicians should use the same normative standards for labor treatment of women without a previous cesarean delivery as has been shown in previous work.

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

OBJECTIVE

We sought to describe labor patterns in women with a trial of labor after cesarean (TOLAC) with normal neonatal outcomes.

STUDY DESIGN

In a retrospective observational study at 12 US centers (2002 through 2008), we examined time interval for each centimeter of cervical dilation and compared labor progression stratified by spontaneous or induced labor in 2892 multiparous women with TOLAC (second delivery) and 56,301 nulliparous women at 37 0/7 to 41 6/7 weeks of gestation. Analyses were performed including women with intrapartum cesarean delivery, and also limiting only to women who delivered vaginally.

RESULTS

Labor was induced in 23.4% of TOLAC and 44.1% of nulliparous women (P < .001). Cesarean delivery rates were 57.7% in TOLAC vs 19.0% in nulliparous women (P < .001). Oxytocin was used in 52.4% of TOLAC vs 64.3% of nulliparous women with spontaneous labor (P < .001) and 89.8% of TOLAC vs 91.6% of nulliparous women with induced labor (P = .099); however, TOLAC had lower maximum doses of oxytocin compared to nulliparous women: median (90th percentile): 6 (18) mU/min vs 12 (28) mU/min, respectively (P < .001). Median (95th percentile) labor duration for TOLAC vs nulliparous women with spontaneous labor from 4-10 cm was 0.9 (2.2) hours longer (P = .007). For women who entered labor spontaneously and achieved vaginal delivery, labor patterns for TOLAC were similar to nulliparous women. For induced labor, labor duration for TOLAC vs nulliparous women from 4-10 cm was 1.5 (4.6) hours longer (P < .001). For women who achieved vaginal delivery, labor patterns were slower for induced TOLAC compared to nulliparous women.

CONCLUSION

Labor duration for TOLAC was slower compared to nulliparous labor, particularly for induced labor. By improved understanding of the rates of progress at different points in labor, this new information on labor curves in women undergoing TOLAC, particularly for induction, should help physicians when managing labor.

Defining an abnormal first stage of labor based on maternal and neonatal outcomes

OBJECTIVE

The objective of the study was to determine the threshold for defining abnormal labor that is associated with adverse maternal and neonatal outcomes.

STUDY DESIGN

This study consisted of a retrospective cohort of all consecutive women admitted at a gestation of 37.0 weeks or longer from 2004 to 2008 who reached the second stage of labor. The 90th, 95th, and 97th percentiles for progress in the first stage of labor were determined specific for parity and labor onset. Women with a first stage above and below each centile were compared. Maternal outcomes were cesarean delivery in the second stage, operative delivery, prolonged second stage, postpartum hemorrhage, and maternal fever. Neonatal outcomes were a composite of the following: admission to level 2 or 3 nursery, 5 minute Apgar less than 3, shoulder dystocia, arterial cord pH of less than 7.0, and a cord base excess of -12 or less.

RESULTS

Of the 5030 women, 4534 experienced first stage of less than the 90th percentile, 251 between the 90th and 94th percentiles, 102 between the 95th and 96th percentiles, and 143 at the 97th percentile or greater. Longer labors were associated with an increased risk of a prolonged second stage, maternal fever, the composite neonatal outcome, shoulder dystocia, and admission to a level 2 or 3 nursery (P < .01). Depending on the cutoff used, 29-30 cesarean deliveries would need to be performed to prevent 1 shoulder dystocia.

CONCLUSION

Although women who experience labor dystocia may ultimately deliver vaginally, a longer first stage of labor is associated with adverse maternal and neonatal outcomes, in particular shoulder dystocia. This risk must be balanced against the risks of cesarean delivery for labor arrest.

Progress of labor in women induced with misoprostol versus the Foley catheter

OBJECTIVE

To estimate and compare the duration and progress of labor in women induced with misoprostol vs Foley catheter plus oxytocin.

STUDY DESIGN

We performed a retrospective cohort study of labor progress among 617 consecutive term pregnancies induced with misoprostol (n = 503) or Foley catheter plus oxytocin (n = 114) who completed the first stage of labor. Labor duration and progress in the entire cohort, and stratified by parity, were compared in multivariable interval-censored regression models adjusting for maternal obesity and birthweight. Repeated-measures analysis with 9th degree polynomial modeling was used to construct average labor curves.

RESULTS

Total duration of labor was not significantly different in women induced with misoprostol compared with the Foley catheter (median duration from 1 to 10 cm: 12 vs 14.2 hours, P = .19). Progress from 1 to 4 cm was more rapid with the Foley catheter (median: 3.4 vs 5.6 hours, P < .01), although progress from 4 to 10 cm was slower (median: 6.3 vs 3.6 hours, P < .01). Labor curves demonstrated transition from latent to active labor at about 4 cm cervical dilatation with misoprostol and at 6 cm for the Foley catheter. Similar general patterns were noted for nulliparous and multiparous women, except for a shorter duration of labor with the Foley catheter among multiparous women.

CONCLUSION

Induction of labor with the Foley catheter is associated with more rapid initial cervical dilation, but transition to active labor occurs later compared with misoprostol. These differences should be considered in the management of induced labor.

The pattern of labor preceding uterine rupture

OBJECTIVE

We sought to characterize the labor of women attempting trial of labor after cesarean (TOLAC) who experience uterine rupture.

STUDY DESIGN

We conducted a secondary analysis of a nested case-control study of women attempting TOLAC. Women experiencing uterine rupture (cases) were compared to 2 reference groups: successful TOLAC and failed TOLAC. Interval-censored regression was used to estimate the median time to progress 1 cm in dilation and the total time from 4-10 cm.

RESULTS

A total of 115 cases were compared to 341 successful TOLAC and 120 failed TOLAC. The time to progress 1 cm was similar between groups until 7-cm dilation. After 7 cm, cases of uterine rupture required longer to progress than successful TOLAC (median [95th percentile] time from 7-8 cm: 0.38 [1.91] vs 0.16 [0.79] hours; from 8-9 cm: 0.28 [1.10] vs 0.10 [0.39] hours). Women with a uterine rupture had labor curves similar to those with a failed TOLAC.

CONCLUSION

Women with labor dystocia in the active phase of labor should be closely monitored for uterine rupture in TOLAC.