Timing of delivery and pregnancy outcomes among laboring nulliparous women

Impact of the ARRIVE Trial in Nulliparous Individuals with Morbid Obesity: Interrupted Time Series Analysis

OBJECTIVE

 We aimed to examine rates of induction of labor at 39 weeks and cesarean delivery before and after the ARRIVE (A Randomized Trial of Induction Versus Expectant Management) trial stratified by body mass index (BMI; kg/m2) category.

STUDY DESIGN

 This was a repeated cross-sectional analysis of publicly available U.S. birth certificate data from 2015 to 2021. We limited analyses to nulliparous individuals with a singleton pregnancy, cephalic presentation, without chronic hypertension, diabetes (gestational or pregestational), and fetal anomaly who delivered between 39 and 42 weeks' gestation. The pre-ARRIVE period spanned from August 2016 to July 2018 and the post-ARRIVE period spanned from January 2019 to December 2020. The dissemination period of the ARRIVE trial was from August 2018 to December 2018. Our co-primary outcomes were induction at 39 weeks and cesarean delivery. Our secondary outcomes were overall induction of labor and preeclampsia. We conducted an interrupted time series analysis after stratifying by prepregnancy BMI (<40 or ≥40). Negative binomial regression was used to calculate adjusted incident rate ratios with 95% confidence intervals.

RESULTS

 Of 2,122,267 individuals that were included, 2,051,050 had BMI <40 and 71,217 had BMI ≥40. In individuals with BMI <40, the post-ARRIVE period compared to the pre-ARRIVE period was associated with an increased rate of induction of labor at 39 weeks, a decreased rate of cesarean delivery, and an increased rate of overall induction of labor. In individuals with BMI ≥40, the post-ARRIVE period compared to the pre-ARRIVE period was associated with an increased rate of induction of labor at 39 weeks, an increased rate of overall induction of labor and a decreased rate of preeclampsia; however, the decrease in the rate of cesarean delivery was not significant.

CONCLUSION

 An increase in induction of labor at 39 weeks' gestation in individuals with BMI ≥40 was not associated with a decrease in the cesarean delivery rate.

KEY POINTS

· The ARRIVE trial increased 39-week labor inductions in BMI <40 and ≥40.. · BMI <40 had fewer cesareans; BMI ≥40 showed no significant decrease.. · Offering labor induction is reasonable as cesarean rates didn't increase..

Changes in obstetrical practices and pregnancy outcomes following the ARRIVE trial

BACKGROUND

The ARRIVE trial demonstrated the benefit of induction of labor at 39 weeks gestation. Obstetrics departments across the United States faced the challenge of adapting clinical practice in light of these data while managing logistical constraints.

OBJECTIVE

To determine if there were changes in obstetrical practices and perinatal outcomes in the United States after the ARRIVE trial publication.

STUDY DESIGN

This was a population-based retrospective cohort study of low-risk, nulliparous women who initiated prenatal care by 12 weeks gestation with singleton, nonanomalous pregnancies delivering at ≥39 weeks. Data were obtained from the US Natality database. The pre-ARRIVE group were women who delivered between January 1, 2015 and December 31, 2017. The post-ARRIVE group consisted of women who delivered between January 1, 2019 and December 31, 2019. Births that occurred in 2018 were excluded. Practice outcomes were rates of induction of labor, timing of delivery, and cesarean delivery rate. Adverse maternal outcomes were blood transfusion and admission to medical intensive care unit. Adverse neonatal outcomes were need for assisted ventilation (immediate and >6 hours), 5-minute APGAR score <3, neonatal intensive care unit admission, seizures, and surfactant use. Univariate and multivariate analyses were performed. Trends were tested across the time period represented by the pre-ARRIVE group using Cochran-Armitage trend test.

RESULTS

There were 1,966,870 births in the pre-ARRIVE group and 609,322 in the post-ARRIVE group. The groups differed in age, race, body mass index, marital status, infertility treatment, and smoking history (P<.001). After adjusting for these differences, the post-ARRIVE group was more likely to undergo induction (36.1% vs 30.2%; adjusted odds ratio, 1.36 [1.36-1.37]) and deliver by 39+6 weeks of pregnancy (42.8% vs 39.9%; adjusted odds ratio, 1.14 [1.14-1.15]). The post-ARRIVE group had a significantly lower rate of cesarean delivery than the pre-ARRIVE group (27.3 % vs 27.9%; adjusted odds ratio, 0.94 [0.93-0.94]). Patients in the post-ARRIVE group were more likely to receive a blood transfusion (0.4% vs 0.3%; adjusted odds ratio, 1.43 [1.36-1.50]) and be admitted to medical intensive care unit (0.09% vs 0.08%; adjusted odds ratio, 1.20 [1.09-1.33]). Neonates in the post-ARRIVE group were more likely to need assisted ventilation at birth (3.5% vs 2.8%; adjusted odds ratio, 1.28 [1.26-1.30]) and >6 hours (0.6% vs 0.5%; adjusted odds ratio, 1.36 [1.31-1.41]). The neonates in the post-ARRIVE group were more likely to have low 5-minute APGAR scores (0.4% vs 0.3%; adjusted odds ratio, 0.91 [0.86-0.95]). Neonatal intensive care unit admission did not differ between the 2 groups (4.9% vs 4.9%; adjusted odds ratio, 1.01 [0.99-1.03]). There were no differences in neonatal seizures (0.04% vs 0.04%; adjusted odds ratio, 0.97 [0.84-1.13]), and surfactant use (0.08% vs 0.07%; adjusted odds ratio, 1.05 [0.94-1.17]) between the 2 groups.

CONCLUSION

There were more inductions of labor, more deliveries at 39 weeks' gestation, and fewer cesarean deliveries in the year after the ARRIVE trial publication. The small but statistically significant increase in some adverse maternal and neonatal outcomes should be explored to determine if they are related with concurrent changes in obstetrical practices.

Adverse Outcomes among Low-Risk Pregnancies at 39 to 41 Weeks: Stratified by Birth Weight Percentile

OBJECTIVE

This study aimed to assess the risk of adverse outcomes among low-risk pregnancies at 39 to 41 weeks, stratified by birth weight percentile.

STUDY DESIGN

This retrospective cohort study utilized the U.S. vital statistics datasets (2013-2017) and evaluated low-risk women with nonanomalous cephalic singleton gestations who labored and delivered at 39 to 41 weeks, regardless of ultimate mode of delivery. Newborns were categorized as small (<10th percentile), large (>90th percentile), or appropriate (10-90th percentile) for gestational ages (SGA, LGA, and AGA, respectively). The primary outcome, composite neonatal adverse outcome (CNAO), included Apgar's score <5 at 5 minutes, assisted ventilation >6 hours, seizure, or neonatal death. The secondary outcome, composite maternal adverse outcome (CMAO), included intensive care unit admission, blood transfusion, uterine rupture, or unplanned hysterectomy. Multivariable Poisson's regression was used to estimate the association (using adjusted relative risk [aRR] and 95% confidence interval [CI]).

RESULTS

Of 19.8 million live births during the study interval, approximately 8.9 million (44.9%) met the inclusion criteria, with 9.9% being SGA, 9.2% being LGA, and 80.9% being AGA. SGA newborns delivered at 40 (aRR = 1.17; 95% CI: 1.12-1.23) and at 41 weeks (aRR = 1.55; 95% CI: 1.45-1.66) had a higher risk of CNAO than at 39 weeks. Similarly, LGA newborns delivered at 40 (aRR = 1.13; 95% CI: 1.07-1.19) and 41 weeks (aRR = 1.44; 95% CI: 1.35-1.54) and AGA newborns delivered at 40 (aRR = 1.24; 95% CI: 1.21-1.26) and 41 weeks (aRR = 1.57; 95% CI: 1.53-1.61) also had a higher risk of CNAO than at 39 weeks. CMAO was also significantly higher at 40 and 41 weeks than at 39 weeks, regardless of whether the mothers delivered SGA, LGA, or AGA newborns.

CONCLUSION

Among low-risk pregnancies, the risks of composite neonatal and maternal adverse outcomes increase from 39 through 41 weeks' gestation, irrespective of whether newborns are SGA, LGA, or AGA.

Neonatal and Maternal Composite Adverse Outcomes Among Low-Risk Nulliparous Women Compared With Multiparous Women at 39-41 Weeks of Gestation

OBJECTIVE

To estimate whether the frequency of adverse maternal and neonatal outcomes differs between low-risk nulliparous and multiparous women at 39-41 weeks of gestation.

METHODS

This is a secondary analysis of an observational obstetrics cohort of maternal-neonatal dyads at 25 hospitals. Low-risk women with nonanomalous singletons who delivered between 39 0/7 and 41 6/7 weeks of gestation were included. The composite neonatal adverse outcome included 5-minute Apgar score less than five, ventilator support or cardiopulmonary resuscitation, seizure, hypoxic ischemic encephalopathy, sepsis, bronchopulmonary dysplasia, persistent pulmonary hypertension, necrotizing enterocolitis, birth injury or perinatal death. The composite maternal adverse outcome included infection, third- or fourth-degree perineal laceration, thromboembolism, transfusion of blood products, or maternal death. Small for gestational age (SGA), large for gestational age (LGA), and shoulder dystocia requiring maneuvers were also evaluated. Multivariable regression was used to estimate adjusted relative risks (aRRs) and adjusted odds ratios (aORs) with 95% CIs.

RESULTS

Of the 115,502 women in the overall cohort, 39,870 (34.5%) met eligibility criteria for this analysis; 18,245 (45.8%) were nulliparous. The risk of the composite neonatal adverse outcome (1.5% vs 1.0%, aRR 1.80, 95% CI 1.48-2.19), composite maternal adverse outcome (15.1% vs 3.3%, aRR 5.04, 95% CI 4.62-5.49), and SGA (8.9% vs 5.8%, aOR 1.45, 95% CI 1.33-1.57) was significantly higher in nulliparous than multiparous patients. The risk of LGA (aOR 0.65, 95% CI 0.60-0.71) and shoulder dystocia with maneuvers (aRR 0.68, 95% CI 0.60-0.77) was significantly lower in nulliparous rather than multiparous patients.

CONCLUSION

The risk of composite adverse outcomes and SGA among low-risk nulliparous women at 39-41 weeks of gestation is significantly higher than among multiparous counterparts. However, nulliparous women had a lower risk of shoulder dystocia with maneuvers and LGA.

Hypoxic-ischemic brain injury: Planned delivery before intrapartum events

BACKGROUND

Mothers are increasingly given greater control over many of the choices around birth, although there is little robust evidence to inform these choices. After an infant is born with HIE the question of whether it was predictable, or preventable, is often raised. Intrapartum 'sentinel' events and antenatal predictors of HIE have been well described, however there is little evidence how antenatal and intrapartum factors interact. This is particularly important when elective delivery by lower segment caesarean section (LSCS) has been shown to be beneficial in high risk groups.

AIM

To develop a clinical risk score to identify women with a higher risk of having an infant with HIE.

PATIENTS AND METHODS

This study is based on the Avon Longitudinal Study of Parents and Children (ALSPAC). This dataset was split into two halves: with each infant being randomly allocated to either cohort one or two. The first cohort was used for the derivation of the model, while it was tested exclusively on the second. Logistic regression modelling was then performed to develop a predictive model. The final model was used to predict the outcome of infants in the second cohort and infants divided into four risk quartiles. To give some indication of possible avoidable disease, the proportion of infants with HIE, potentially avoided by earlier delivery, was estimated by assuming that medicalized delivery by elective LSCS at 37 weeks would remove intrapartum risk of HIE for those infants undelivered at this point.

RESULTS

In the final model seven covariates remained (parity, preeclampsia, polyhydramnios, prelabor rupture of membranes, gender, concerns over fetal growth and prematurity). When applied to the second cohort, a ROC curve for the prediction of developing HIE in the newborn period showed good evidence for association (AUC 0.68 (0.60 to 0.77)) and the risk score derived was strongly associated with the risk of HIE, resuscitation and stillbirth, and neonatal death (all p < 0.05). Elective delivery of high risk infants at 37 weeks gestation could prevent 14% of all HIE, with a NNT of 41.

CONCLUSION

It is possible to combine routine antenatal findings to identify infants at higher risk of neonatal HIE, thereby recognizing those infants who may benefit most from delivery by elective caesarean section. This work suggests a clinical risk score permits antenatal identification of high-risk infants whose outcome may be amenable to changes in clinical practice to potentially reduce HIE rates, and its devastating consequences.

Association between provider type and cesarean birth in healthy nulliparous laboring women: A retrospective cohort study

BACKGROUND

Term nulliparous women have the greatest variation across hospitals and providers in cesarean rates and therefore present an opportunity to improve quality through optimal care. We evaluated associations between provider type and mode of birth, including examination of intrapartum management in healthy, laboring nulliparous women.

METHODS

Retrospective cohort study using prospectively collected perinatal data from a United States academic medical center (2005-2012). The sample included healthy nulliparous women with spontaneous labor onset and term, singleton, vertex fetus managed by either obstetricians or certified nurse-midwives. Univariate and multivariate logistic regression was used to compare labor interventions and mode of birth by provider type.

RESULTS

A total of 1339 women received care by an obstetrician (n = 749) or nurse-midwife (n = 590). The cesarean rate was 13.4% (179/1339). Adjusting for maternal and pregnancy characteristics, care by obstetricians was associated with an increased risk of unplanned cesarean birth (adjusted odds ratio [aOR] 1.48 [95% confidence interval {CI} 1.04-2.12]) compared with care by midwives. Obstetricians more frequently used oxytocin augmentation (aOR 1.41 [95% CI 1.10-1.80]), neuraxial anesthesia (aOR 1.69 [95% CI 1.29-2.23]), and operative vaginal delivery with forceps or vacuum (aOR 2.79 [95% CI 1.75-4.44]). Adverse maternal or neonatal outcomes were not different by provider type across all modes of birth, but were more frequent in women with cesarean than vaginal births.

DISCUSSION

In low-risk nulliparous laboring women, care by obstetricians compared with nurse-midwives was associated with increased risk of labor interventions and operative birth. Changes in labor management or increased use of nurse-midwives could decrease the rate of a first cesarean in low-risk laboring women.

Associations between birth at, or after, 41 weeks gestation and perinatal encephalopathy: a cohort study

BACKGROUND

Preterm birth causes long-term problems, even for infants born 1 or 2 weeks early. However, less is known about infants born after their due date and over a quarter of infants are born over 1 week late, and many still remain undelivered after 2 weeks. The aim of this work is to quantify the risks of infants developing encephalopathy when birth occurs after the due date, and if other proposed risk factors modify this relationship.

METHODS

The dataset contain information on 4 036 346 infants born in Sweden between 1973 and 2012. Exposure was defined as birth 7, or more, days after the infants' due date. The primary outcome was the development of neonatal encephalopathy (defined as seizures, encephalopathy or brain injury caused by asphyxia or with unspecified cause). Covariates were selected as presumed confounders a priori.

RESULTS

28.4% infants were born 1 or more weeks after their due date. An infant's risk of being born with encephalopathy was higher in the post 41 weeks group in the unadjusted (OR 1.40 (95% CI 1.32 to 1.49)) and final model (OR 1.38 (95% CI 1.29 to 1.47)), with the relative odds of encephalopathy increasing by an estimated 20% per week after the due date, and modified by maternal age (P=0.022).

CONCLUSIONS

Singleton infants born at, or after, 41 weeks gestation have lower Apgar scores and higher risk of developing encephalopathy in the newborn period, and the association appeared more marked in older mothers. These data could be useful if provided to women as part of their decision-making.

Outcome of the vaginal birth after cesarean section during the second birth order in West Kazakhstan

Background

Vaginal birth after cesarean section (VBAC) increases the chance of subsequent vaginal deliveries and reduces the repeat cesarean section (CS) rate with subsequent postoperative morbidity.

Objectives

To detect the outcome of VBAC during the second birth order in Aktobe region of West Kazakhstan.

Patients and Methods

A total of 832 women eligible for trial of VBAC were included in this study. Women who signed the consent of VBAC were evaluated thoroughly and data such as maternal age, body mass index, height, gestational age at admission, indication of the previous CS, estimated fetal weight, engagement of the fetal head, condition of the membranes, and cervical dilatation were collected. Data collected after delivery include duration from active phase of labor, mode of delivery, fetal, and neonatal outcomes. The collected data analyzed to detect the outcome of trial of VBAC during the second birth order in Aktobe region of West Kazakhstan.

Results

Logistic analysis and odds ratio (OR) showed that body mass index (BMI) ≤25 kg/m² (OR 1.7; P = 0.0004), height ≥150 cm (OR 1.7; P = 0.002), gestational age ≤40 weeks (OR 2.3; P = 0.0001), and inter-delivery interval ≥2 years (OR 1.6; P = 0.008) were significantly associated with successful VBAC. In addition, <2/5 of the fetal head palpable abdominally, station <-2 (OR 1.7; P = 0.0009), cervical dilatation ≥4 cm (OR 1.7; P = 0.003), and duration of active phase of labor ≤7 h (OR 1.6; P = 0.01) were significantly associated with successful VBAC.

Conclusion

VBAC is safe in properly selected cases. BMI ≤25 kg/m², gestational age ≤40 weeks, inter-delivery interval ≥2 years, and fetal head <-2 station increase the success of VBAC. Prolonged active phase of labor >7 h and the need for labor augmentation decrease the chance of VBAC success.

Racial disparities in the optimal for induction of labor in low-risk term pregnancies: a national population-based study

OBJECTIVE

The recommendation for elective induction of labor (IOL) is to await ≥ 39 weeks. Studies show earlier maturity of Blacks compared to Whites. The objective was to examine the effect of the Black race on the risk of intrapartum and neonatal complications after IOL.

METHODS

Black women with non-indicated IOL at 37-42 weeks were selected from the CDC-Birth Cohorts 2007-2010. Congenital anomalies, hypertension/diabetes, low-birth weight, breech presentation, previous cesarean and premature rupture of membranes were excluded. Intrapartum/neonatal complications were analyzed. Logistic regression was used to calculate adjusted odds ratios, using 39 weeks as reference.

RESULTS

311,264 black were compared with 2,451,774 deliveries of other races. For Blacks, the risks of cesarean delivery and intrapartum complications were lower at 38 weeks. Chance of vaginal delivery was greater at 38 weeks. Risks of neonatal complications was not increased at 38 compared to 39 weeks.

CONCLUSIONS

Intrapartum complications were lower at 38 than at 39 weeks in Blacks with no increased risk of neonatal complications. Meconium staining and fetal distress were higher as early as at 40 weeks, perhaps due to accelerated maturation. While a 39-week goal is simple and benefits many patients, a more "personalized medicine" approach may benefit even more mothers and babies.

[Predictors of failed trial of labor in obese nulliparous]

OBJECTIVES

To identify predictors of failed trial of labour (TOL) in obese nulliparous at term.

PATIENTS AND METHODS

Retrospective study about 213 nulliparous with a body mass index (BMI) greater than 30kg/m(2) who delivered a vertex singleton after 37 weeks of gestation (WG). Planned caesarean sections were excluded. Maternal, sonographic, per-partum and neonatal characteristics were analyzed according to the mode of entry into labor and delivery route. Univariate and multivariate logistic regression analysis were performed.

RESULTS

The cesarean delivery rate was 28%. Induction of labor (aOR=4.3 [1.8-10.7]), prolonged pregnancy (aOR=10.8 [1.7-67.6]), macrosomia (aOR=5.6 [1.1-27.3]), meconium-stained amniotic fluid (aOR: 2.57 [1.03-6.42]), use of trinitrine (aOR=5.5 [1.39-21.6]) and neonatal head circumference greater than 35cm (aOR=3.1 [1.2-8.0]) were predictors of failed TOL. There was no significant correlation between failed TOL and preconceptional BMI. Univariate analysis revealed an association between excessive weight gain and failed TOL.

DISCUSSION AND CONCLUSION

Predictors of failed TOL are the same in obese and non-obese women. Preconceptional BMI does not predict failed TOL in this nulliparous obese population.

Maternal and obstetrical factors associated with a successful trial of vaginal birth after cesarean section

OBJECTIVE

To detect the maternal and obstetrical factors associated with successful trial of vaginal birth among women with a previous cesarean delivery.

MATERIAL AND METHODS

A total of 122 women who were eligible for a trial of labor after cesarean section (TOLAC) according to departmental protocol were included in this comparative prospective study. After informed consent, the women included in this study were subjected to a thorough history to detect maternal and obstetric characteristics and a standard examination to estimate fetal weight, engagement of the fetal head, intra-partum features of fetal membranes, and cervical dilatation. After delivery, data on duration of labor, labor augmentation, mode of delivery, birth outcome, and neonatal intensive care (NICU) admission were recorded and analyzed.

RESULTS

Trial of labor after cesarean section was successful in 72.13% and was unsuccessful in 27.87%. Body mass index (BMI) was significantly lower in the successful TOLAC group compared to the unsuccessful group (23.8±0.03 versus 26.2±0.02 kg/m(2)), and the number of women with BMI >25 kg/m(2) was significantly high in the unsuccessful group; also, mean gestational age was significantly lower in the successful TOLAC group compared to the unsuccessful group (37.5±0.04 versus 38.5±0.03 weeks), and the number of women admitted in labor with gestation ≥40 weeks was significantly high in the unsuccessful group. The number of women admitted with >2/5 of fetal head palpable abdominally and fetal head station ≥-2 was significantly high in the unsuccessful TOLAC group.

CONCLUSION

In carefully selected cases, TOLAC is safe and often successful. Presence of BMI >25 kg/m(2), gestation ≥40 weeks, and vertex station ≥-2 were risk factors for unsuccessful TOLAC.

The risk of stillbirth and infant death by each additional week of expectant management stratified by maternal age

OBJECTIVE

The objective of the study was to examine fetal/infant mortality by gestational age at term stratified by maternal age.

STUDY DESIGN

A retrospective cohort study was conducted using 2005 US national birth certificate data. For each week of term gestation, the risk of mortality associated with delivery was compared with composite mortality risk of expectant management. The expectant management measure included stillbirth and infant death. This expectant management risk was calculated to estimate the composite mortality risk with remaining pregnant an additional week by combining the risk of stillbirth during the additional week of pregnancy and infant death risk following delivery at the next week. Maternal age was stratified by 35 years or more compared with women younger than 35 years as well as subgroup analyses of younger than 20, 20-34, 35-39, or 40 years old or older.

RESULTS

The fetal/infant mortality risk of expectant management is greater than the risk of infant death at 39 weeks' gestation in women 35 years old or older (15.2 vs 10.9 of 10,000, P < .05). In women younger than 35 years old, the risk of expectant management also exceeded that of infant death at 39 weeks (21.3 vs 18.8 of 10,000, P < .05). For women younger than 35 years old, the overall expectant management risk is influenced by higher infant death risk and does not rise significantly until 41 weeks compared with women 35 years old or older in which it increased at 40 weeks.

CONCLUSION

Risk varies by maternal age, and delivery at 39 weeks minimizes fetal/infant mortality for both groups, although the magnitude of the risk reduction is greater in older women.

Obstetric factors for unsuccessful trial of labor in second-order birth following previous cesarean

BACKGROUND AND OBJECTIVES

The trial of labor after previous cesarean (TOLAC) is an important strategy to limit repeat cesarean sections and their complications. An unsuccessful TOLAC leads to maternal and neonatal morbidities. The success or failure of TOLAC after the first cesarean is determinant for the subsequent vaginal birth. Limited studies are available from low-income countries, exclusively conducted in women in their sec.ond-order birth following the first cesarean section. This study aims at determining the frequency of unsuccessful attempts at vaginal delivery in the second-order term (37-41+6/7 weeks) birth among women with previous cesarean sections and to describe maternal and obstetric factors for unsuccessful laborTOLACs in the same group.

DESIGN AND SETTINGS

A cross-sectional study conducted from April to December 2010 at Obstetrics & Gynaecology Unit II, Civil Hospital Karachi.

PATIENTS AND METHODS

All eligible patients at term pregnancy in their second-order birth were included. The frequency of unsuccessful attempts at vaginal birth was determined, followed by secondary analysis by calculating odds ratio for maternal and obstetric factors, that is, body mass index (BMI), hight, gestation ≥40 weeks, interdelivery interval, engagement of head in 5th, estimated fetal weight, ruptured membranes, duration of labor ≥7 hours, augmentation of labor, cervical dilatation < 4 cm, and vertex station -2 or higher on admission.

RESULTS

Out of 122 study subjects, the proportion of unsuccessful vaginal birth after cesarean (VBAC) was 27.9% (n=34). Among maternal and obstetric factors, BMI > 25 (AOR, 5.00), gestation ≥40 weeks (AOR, 5.45), cervical dilatation < 4 cm (AOR, 5.90), and station of vertex -2 or higher (AOR, 3.83) had highly significant adjusted odds for failed TOLAC.

CONCLUSION

With a well-defined protocol, the rates of unsuccessful attempts at VBAC are not high for the second-order birth. The risk of failure can be anticipated by factors such as BMI > 25, pregnancy duration ≥40 weeks, cervical dilatation < 4 cm, and vertex station -2 or higher on admission.