Second-Stage Duration and Outcomes Among Women Who Labored After a Prior Cesarean Delivery

Evaluating the impact of a trial of labor after cesarean section on labor duration: a retrospective cohort study

BACKGROUND

Cesarean section (C-section) rates are increasing globally, and repeated C-sections are associated with increased maternal morbidity. Trial of labor after C-section (TOLAC) is an approach to reduce the recurrence of C-sections. However, limited research exists on the impact of cesarean scars on labor duration in TOLAC, considering the termination of labor through C-section and selection bias. This study aimed to investigate the impact of cesarean scars on labor duration in TOLAC participants, accounting for potential confounding factors and biases.

METHODS

This retrospective cohort study included 2,964 women who attempted vaginal birth at a single center in Japan from 2012 to 2021. The study categorized participants into TOLAC (n = 187) and non-TOLAC (n = 2,777) groups. Propensity scores were calculated based on 14 factors that could influence labor duration, and inverse probability of treatment weighting (IPTW) was applied. Cox proportional hazards regression analysis estimated hazard ratios (HRs) for labor duration, with and without IPTW adjustment. Sensitivity analyses used propensity score matching, bootstrapping, and interval censoring to address potential biases, including recall bias in the reported onset of labor.

RESULTS

The unadjusted HR for labor duration in the TOLAC group compared to the non-TOLAC group was 0.83 (95% CI: 0.70-0.98, P = 0.027), indicating a longer labor duration in the TOLAC group. After adjusting for confounding factors using IPTW, the HR was 0.98 (95% CI: 0.74-1.30, P = 0.91), suggesting no significant difference in labor duration between the groups. Sensitivity analyses using propensity score matching, bootstrapping, and interval censoring yielded consistent results. These findings suggested that the apparent association between TOLAC and longer labor duration was because of confounding factors rather than TOLAC itself.

CONCLUSIONS

After adjusting for confounding factors and addressing potential biases, cesarean scars had a limited impact on labor duration in TOLAC participants. Maternal and fetal characteristics may have a more substantial influence on labor duration.

The Role of Passive Descent and Epidural Analgesia in Outcomes Associated With Prolonged Pushing Among Nulliparous Individuals in Midwifery Care

INTRODUCTION

Efforts to reduce primary cesarean birth may include supporting longer second stages of labor. Although midwifery-led care is associated with lower cesarean use, little has been published on associated outcomes of prolonged second stage (≥3 hours of pushing) for nulliparous individuals in US hospital-based midwifery care. Epidural analgesia and the role of passive descent in midwifery-led care are also underexplored in relation to the second stage. In this study, we report the incidence of prolonged second stage stratified by epidural analgesia and/or passive descent. Secondary aims included calculating the odds of cesarean birth, obstetric anal sphincter injury (OASI), postpartum hemorrhage (PPH), and neonatal complications.

METHODS

Data were collected prospectively from a single academic center in the United States from 2012 through 2019. Our cohort analysis of labors attended by midwives for nulliparous, term, singleton, and vertex pregnancies included both descriptive and inferential statistics comparing outcomes between prolonged versus nonprolonged pushing groups. We stratified the sample and quantified second stage outcomes by epidural analgesia and by use of passive descent.

RESULTS

Of the 1465 births, 17% (n = 247) included prolonged pushing. Cesarean ranged from 2.2% without prolonged pushing to 26.7% with prolonged pushing. Fetal malposition, epidural analgesia, and longer passive descent were more common among those with prolonged active pushing. Despite these factors, neither odds for PPH nor poor neonatal outcomes were associated with prolonged pushing. Those with more than one hour of passive descent in the second stage who also had prolonged active pushing had lower odds for cesarean but higher odds for OASI relative to those who had little passive descent before pushing for more than 3 hours.

DISCUSSION

Prolonged pushing occurred in nearly 2 of 10 nulliparous labors. Fetal malposition, epidural analgesia, and prolonged pushing were commonly observed with longer passive descent, cesarean, and OASI. Passive descent in these data likely reflects individualized midwifery care strategies when pushing was complicated by fetal malposition or other complexities.

Trial of labor after cesarean, vaginal birth after cesarean, and the risk of uterine rupture: an expert review

The decision to pursue a trial of labor after cesarean delivery is complex and depends on patient preference, the likelihood of successful vaginal birth after cesarean delivery, assessment of the risks vs benefits of trial of labor after cesarean delivery, and available resources to support safe trial of labor after cesarean delivery at the planned birthing center. The most feared complication of trial of labor after cesarean delivery is uterine rupture, which can have catastrophic consequences, including substantial maternal and perinatal morbidity and mortality. Although the absolute risk of uterine rupture is low, several clinical, historical, obstetrical, and intrapartum factors have been associated with increased risk. It is therefore critical for clinicians managing patients during trial of labor after cesarean delivery to be aware of these risk factors to appropriately select candidates for trial of labor after cesarean delivery and maximize the safety and benefits while minimizing the risks. Caution is advised when considering labor augmentation and induction in patients with a previous cesarean delivery. With established hospital safety protocols that dictate close maternal and fetal monitoring, avoidance of prostaglandins, and careful titration of oxytocin infusion when induction agents are needed, spontaneous and induced trial of labor after cesarean delivery are safe and should be offered to most patients with 1 previous low transverse, low vertical, or unknown uterine incision after appropriate evaluation, counseling, planning, and shared decision-making. Future research should focus on clarifying true risk factors and identifying the optimal approach to intrapartum and induction management, tools for antenatal prediction, and strategies for prevention of uterine rupture during trial of labor after cesarean delivery. A better understanding will facilitate patient counseling, support efforts to improve trial of labor after cesarean delivery and vaginal birth after cesarean delivery rates, and reduce the morbidity and mortality associated with uterine rupture during trial of labor after cesarean delivery.

Second stage duration and delivery outcomes among women laboring after cesarean with no prior vaginal delivery

BACKGROUND

We aimed to evaluate the association of the duration of the second stage with labor after cesarean (LAC) success and other outcomes among women with one prior cesarean delivery (CD) and no prior vaginal births.

METHODS

All women undergoing LAC that reached the second stage of labor from March 2011 to March 2020 were included in this retrospective cohort study. The primary outcome was the mode of delivery by second stage duration. The secondary outcomes included adverse maternal and neonatal outcomes. We allocated the study cohort into five groups of second stage duration. Further analysis compared <3 to ≥3 h of second stage based on prior studies. LAC success rates were compared. Composite maternal outcome was defined as the presence of uterine rupture/dehiscence, postpartum hemorrhage, or intrapartum/postpartum fever.

RESULTS

One thousand three hundred ninety seven deliveries were included. Vaginal birth after cesarean (VBAC) rates decreased as the second stage length time interval increased: 96.4% at <1 h, 94.9% at 1 to <2 h, 94.6% at 2 to <3 h, 92.1% at 3 to <4 h and 79.5% at ≥4 h (p < 0.001). Operative vaginal and CDs were significantly more likely as second stage duration time interval increased (p < 0.001). The composite maternal outcome was comparable among groups (p = 0.226). When comparing the outcomes of deliveries at <3 h versus ≥3 h, the composite maternal outcome and neonatal seizure rates were lower in the <3 h group (p = 0.041 and p = 0.047, respectively).

CONCLUSION

Vaginal birth after cesarean rates decreased as second stage time interval length increased. Even with prolonged second stage, VBAC rates remained relatively high. Increased risk of composite adverse maternal outcomes and neonatal seizures were observed when the second stage lasted 3 h or more.

Approaches to Preventing Intrapartum Fetal Injury

Electronic fetal monitoring (EFM) was introduced into obstetric practice in 1970 as a test to identify early deterioration of fetal acid-base balance in the expectation that prompt intervention ("rescue") would reduce neonatal morbidity and mortality. Clinical trials using a variety of visual or computer-based classifications and algorithms for intervention have failed repeatedly to demonstrate improved immediate or long-term outcomes with this technique, which has, however, contributed to an increased rate of operative deliveries (deemed "unnecessary"). In this review, we discuss the limitations of current classifications of FHR patterns and management guidelines based on them. We argue that these clinical and computer-based formulations pay too much attention to the detection of systemic fetal acidosis/hypoxia and too little attention not only to the pathophysiology of FHR patterns but to the provenance of fetal neurological injury and to the relationship of intrapartum injury to the condition of the newborn. Although they do not reliably predict fetal acidosis, FHR patterns, properly interpreted in the context of the clinical circumstances, do reliably identify fetal neurological integrity (behavior) and are a biomarker of fetal neurological injury (separate from asphyxia). They provide insight into the mechanisms and trajectory (evolution) of any hypoxic or ischemic threat to the fetus and have particular promise in signaling preventive measures (1) to enhance the outcome, (2) to reduce the frequency of "abnormal" FHR patterns that require urgent intervention, and (3) to inform the decision to provide neuroprotection to the newborn.

Association between the second-stage duration of labor and perinatal outcomes in women with a prior cesarean delivery

BACKGROUND

The cesarean delivery (CD) rate has been increasing globally. Trial of labor after cesarean delivery (TOLAC) has been used as a key method for the reduction of the CD rate. Little is known, however, about the association between the second-stage duration of TOLAC and adverse maternal and neonatal outcomes. This study evaluated the association between perinatal outcomes and the duration of second-stage labor in women undergoing TOLAC.

METHODS

A 10-year retrospective cohort study was performed at the Department of Obstetrics and Gynecology, Third Affiliated Hospital of Guangzhou Medical University, between January 2010 and January 2020. Women undergoing TOLAC who reached the second stage of labor were included in this study. Duration of the second stage of labor was examined as a categorical variable (group I: <0.5 h, group II: 0.5-2 h and group III: ≥2 h) and as a continuous variable to evaluate the association with adverse perinatal outcomes by using multivariable regression models and a Cox proportional hazards regression model adjusting for potential confounders.

RESULTS

Of the 1,174 women who met the inclusion criteria, the median (interquartile range) length of the second stage was 0.5 h (0.3-0.9 h). Among them, 1,143 (97.4%) delivered vaginally and 31 underwent an unplanned CD. As the second-stage duration increased, operative vaginal delivery (OVD), CD, and postpartum hemorrhage (PPH) rates increased. Women in group III had higher risks of OVD (aOR = 11.34; 95% CI [5.06-25.41]), CD (aOR = 4.22; 95% CI [1.32-13.43]), and PPH (aOR = 2.43; 95% CI [1.31-4.50]) compared with group I. Correspondingly, blood loss and the oxytocin used to treat PPH increased significantly, while the postpartum hemoglobin reduced significantly in group III compared with group I. The incidence of uterine rupture, uterine atony, cervical laceration, red blood cell transfusion, and intensive care unit admission were similar in all three groups. Neonatal outcomes were not affected by the second-stage duration.

CONCLUSIONS

Women undergoing TOLAC with second-stage duration of ≥2 h have higher odds of OVD, unplanned intrapartum CD, and PPH.

Second stage cesarean section and the risk of preterm birth in subsequent pregnancies

OBJECTIVE

To evaluate the risk of spontaneous preterm birth on subsequent pregnancies after second stage cesarean section.

METHODS

This is a retrospective cohort study. Women were included if they had their two consecutive births in Toulouse University Hospital in the study period. The first birth was a singleton livebirth at term (≥37 weeks of gestation), divided in three categories according to the mode of delivery: vaginal delivery (group A), cesarean section before the second stage of labor (group B), cesarean section during the second stage of labor (group C). The subsequent pregnancy was the first subsequent pregnancy, conducted after 16 weeks of gestation. The primary outcome was spontaneous preterm birth in the subsequent pregnancy, defined as delivery before 37 weeks of gestation. Secondary endpoints included preterm rupture of membranes in the subsequent pregnancy.

RESULTS

Between 2003 and 2018, 7776 women (84.7%) in group A, 1263 (13.8%) in group B and 143 (1.5%) in group C were included. The adjusted odds ratio of spontaneous preterm birth before 37 weeks of gestation after second stage cesarean section was 2.4 (group C vs group A + B, 95% confidence interval: 1.2-4.8), P = 0.01). The rate of preterm rupture of membranes was also significantly higher in group C (6% vs 2% in group A, P = 0.009, 6% vs 3% in group B, P= 0.05) with OR = 3.0 (group C vs group A + B, 95% CI: 1.55-6.16, P < 0.001).

CONCLUSION

History of term second stage of labor cesarean section is an independent risk factor for spontaneous preterm birth and for preterm rupture of membrane in the subsequent pregnancy.

Time matters-a Swedish cohort study of labor duration and risk of uterine rupture

INTRODUCTION

Uterine rupture is an obstetric emergency associated with maternal and neonatal morbidity. The main risk factor is a prior cesarean section, with rupture occurring in subsequent labor. The aim of this study was to assess the risk of uterine rupture by labor duration and labor management.

MATERIAL AND METHODS

This is a Swedish register-based cohort study of women who underwent labor in 2013-2018 after a primary cesarean section (n = 20 046). Duration of labor was the main exposure, calculated from onset of regular labor contractions and birth; both timepoints were retrieved from electronic medical records for 12 583 labors, 63% of the study population. Uterine rupture was calculated as events per 1000 births at different timepoints during labor. Risk estimates for uterine rupture by labor duration, induction of labor, use of oxytocin and epidural analgesia were calculated using Poisson regression, adjusted for maternal and birth characteristics. Estimates were presented as adjusted rate ratios (ARR) with 95% confidence intervals (CI).

RESULTS

The prevalence of uterine rupture was 1.4% (282/20 046 deliveries). Labor duration was 9.88 hours (95% CI 8.93-10.83) for women with uterine rupture, 8.20 hours (95% CI 8.10-8.31) for women with vaginal delivery, and 10.71 hours (95% CI 10.46-10.97) for women with cesarean section without uterine rupture. Few women (1.0/1000) experienced uterine rupture during the first 3 hours of labor. Uterine rupture occurred in 15.6/1000 births with labor duration over 12 hours. The highest risk for uterine rupture per hour compared with vaginal delivery was observed at 6 hours (ARR 1.20, 95% CI 1.11-1.30). Induction of labor was associated with uterine rupture (ARR 1.54, 95% CI 1.19-1.99), with a particular high risk seen in those induced with prostaglandins and no risk observed with cervical catheter (ARR 1.19, 95% CI 0.83-1.71). Labor augmentation with oxytocin (ARR 1.60, 95% CI 1.25-2.05) and epidural analgesia (ARR 1.63, 95% CI 1.27-2.10) were also associated with uterine rupture.

CONCLUSIONS

Labor duration is an independent factor for uterine rupture among women attempting vaginal delivery after cesarean section. Medical induction and augmentation of labor increase the risk, regardless of maternal and birth characteristics.

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.

Clinical evaluation of labor: an evidence- and experience-based approach

During labor mother and fetus are evaluated at intervals to assess their well-being and determine how the labor is progressing. These assessments require skillful physical diagnosis and the ability to translate the acquired information into meaningful prognostic decision-making. We describe a coordinated approach to the assessment of labor. Graphing of serial measurements of cervical dilatation and fetal station creates "labor curves," which provide diagnostic and prognostic information. Based on these curves we recognize nine discrete labor abnormalities. Many may be related to insufficient or disordered contractile mechanisms. Several factors are strongly associated with development of labor disorders, including cephalopelvic disproportion, excess analgesia, fetal malpositions, intrauterine infection, and maternal obesity. Clinical cephalopelvimetry involves assessing pelvic traits and predicting their effects on labor. These observations must be integrated with information derived from the labor curves. Exogenous oxytocin is widely used. It has a high therapeutic index, but is easily misused. Oxytocin treatment should be restricted to situations in which its potential benefits clearly outweigh its risks. This requires there be a documented labor dysfunction or a legitimate medical reason to shorten the labor. Normal labor and delivery pose little risk to a healthy fetus; but dysfunctional labors, especially if stimulated excessively by oxytocin or terminated by complex operative vaginal delivery, have the potential for considerable harm. Conscientiously implemented, the approach to the evaluation of labor outlined in this review will result in a reasonable cesarean rate and minimize risks that may accrue from the labor and delivery process.

Effect of a two-stage intervention package on the cesarean section rate in Guangzhou, China: A before-and-after study

BACKGROUND

The cesarean section (CS) rate has risen globally during the last two decades. Effective and feasible strategies are needed to reduce it. The aim of this study was to assess the CS rate change after a two-stage intervention package that was designed to reduce the overall CS rate in Guangzhou, China.

METHODS AND FINDINGS

This intervention package was implemented by the Health Commission of Guangzhou Municipality in 2 stages (October 2010-September 2014 and October 2014-December 2016) and included programs for population health education, skills training for healthcare professionals, equipment and technical support for local healthcare facilities, and capacity building for the maternal near-miss care system. A retrospective repeated cross-sectional study was conducted to evaluate influences of the intervention on CS rates. A pre-intervention period from January 2008 to September 2010 served as the baseline. The primary outcome was the CS rate, and the secondary outcomes included maternal mortality ratio (MMR) and perinatal mortality rate (PMR), all obtained from the Guangzhou Perinatal Health Care and Delivery Surveillance System (GPHCDSS). The Cochran-Armitage test was used to examine the trends of the overall CS rate, MMR, and PMR across different stages. Segmented linear regression analysis was used to assess the change of the CS rate over the intervention period. A total of 1,921,932 records of births and 108 monthly CS rates from 2008 to 2016 were analyzed. The monthly CS rate declined across the intervention stages (Z = 75.067, p < 0.001), with an average rate of 42.4% at baseline, 39.8% at Stage 1, and 35.0% at Stage 2. The CS rate declined substantially among nulliparous women who delivered term singletons, with an accelerating decreasing trend observed across Stage 1 and Stage 2 (the difference in slopes: -0.09 [95% CI -0.16 to -0.02] between Stage 1 and baseline, p = 0.014; -0.11 [95% CI -0.20 to -0.02] between Stage 1 and Stage 2, p = 0.017). The CS rate in the remaining population increased during baseline and Stage 1 and subsequently decreased during Stage 2. The sensitivity analysis suggested no immediate impact of the universal two-child policy on the trend of the CS rate. The MMR (Z = -4.368, p < 0.001) and PMR (Z = -13.142, p < 0.001) declined by stage over the intervention period. One of the main limitations of the study is the lack of a parallel control group. Moreover, the influence of temporal changes in the study population on the CS rate was unknown. Given the observational nature of the present study, causality cannot be confirmed.

CONCLUSIONS

Apparent decline in the overall CS rate was observed in Guangzhou, China, after the implementation of a two-stage intervention package. The decline was most evident among nulliparous women who delivered term singletons. Despite some limitations for causal inference, Guangzhou's experience in controlling the CS rate by implementing composite interventions with public health education and perinatal healthcare service improvement could have implications for other similar areas with high rates of CS.