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.

Trial of labor after cesarean in women with hypertensive disorders and no prior vaginal delivery.

KEY MESSAGE: Trial of labor among women who never delivered vaginally with hypertensive disorder is associated with nearly half the success rate of the general population. PURPOSE: To study the trial of labor after cesarean (TOLAC) among women with hypertensive disorders and no prior vaginal delivery. METHODS: A retrospective cohort study was conducted including women with no prior vaginal delivery undergoing TOLAC during 2010-2020. Women with hypertensive disorder were compared to those without. RESULTS: A total of 54/2,144 (2.5%) TOLACs had a hypertensive disorder: 32 (59%) had gestational hypertension, 16 (30%) had chronic hypertension and 6 (11%) had preeclampsia. Women with hypertensive disorders had higher BMI and higher proportion of diabetic disorders. TOLAC success rate was lower among hypertensive mothers: 32 (59%) vs. 1,605 (76.8%), p=0.003 odds ratio (OR), 95% confidence interval (CI) 0.44 (0.25-0.76). The rate of uterine rupture was 23/2,144 (1.1%). In a multivariable logistic regression analysis, hypertensive disorder was independently negatively associated with TOLAC success, adjusted OR (95% CI) 0.47 (0.26-0.85). Other factors negatively independently associated with TOLAC failure were maternal age, predelivery body mass index, dystocia at primary CD, gestational age at TOLAC, induction of labor and birth weight. Epidural was independently positively associated with TOLAC success, adjusted OR (95% CI) 1.54 (1.18-1.99). CONCLUSION: TOLAC in hypertensive women with no prior vaginal delivery is safe. Success rate is impaired in comparison to non-hypertensive women.

Predictors of successful vaginal birth after cesarean without an epidural among women with no prior vaginal delivery.

BACKGROUND: Data are scarce on predictors for success of labor after cesarean (LAC) among women delivering without epidural anesthesia (EA). We aimed to study the predictors for success of LAC among women with no prior vaginal delivery that did not use EA. METHODS: A retrospective study including all women undergoing LAC between 3/2011 and 1/2021 with no prior vaginal delivery that did not use EA. Factors associated with successful vaginal birth after cesarean were examined using multivariable analysis. RESULTS: Of the 466 no EA LAC, 339 (72.7%) delivered vaginally. Women in the successful LAC group had lower pregestational and predelivery BMI as compared to those who had a repeat cesarean [odds ratio (OR) 95% confidence interval (CI) 0.90 (0.85-0.94), P < 0.001, and 0.89 (0.85-0.93), P < 0.001, respectively]. The rate of labor dystocia in previous cesarean was lower in the LAC success group [92 (27.1%) vs 50 (39.4%), OR 95% CI 0.57 (0.37-0.88)]. Mean gestational age at LAC was lower in the LAC success group (385/7  ± 25/7 vs 395/7  ± 15/7 , P = 0.014). In a multivariable logistic regression analysis, the following factors were negatively and independently associated with LAC success: higher predelivery BMI [adjusted odds ratio (aOR) 95% CI 0.90 (0.86-0.95)], higher gestational age at previous cesarean and at LAC [aOR 95% CI 0.81 (0.70-0.93) and 0.97 (0.94-0.98), respectively], induction of labor [aOR 95% CI 0.08 (0.03-0.25)], and duration of ruptured membranes [aOR 95% CI 0.97 (0.96-0.99)]. CONCLUSIONS: We have identified that lower BMI, lower gestational age, shorter ruptured membranes duration, and spontaneous labor are associated with successful LAC among nonusers of EA with no prior vaginal delivery at one tertiary care facility in Israel.

Prediction of successful trial of labor after cesarean among grand-multiparous women.

PURPOSE: To determine the factors associated with successful trial of labor after cesarean (TOLAC) among grand-multiparous (GMP) women. METHODS: A retrospective cohort study was conducted, including all GMP women (≥ 5 deliveries) undergoing TOLAC during 3/2011 and 6/2020, delivering a singleton cephalic newborn. Factors associated with successful vaginal delivery were examined by multivariable analysis. RESULTS: Overall, 381/413 (92.2%) GMP succeeded TOLAC. Maternal characteristics did not differ between TOLAC success and TOLAC failure groups. Previous cesarean delivery characteristics did not differ between study groups. The median number of previous vaginal births after cesarean was 2 [interquartile range 1-4]. Gestational age at TOLAC was lower in the success group (mean 371/7 ± 36/7 vs. 385/7 ± 31/7 weeks, p = 0.028). A lower rate of modified Bishop score < 4 was associated with TOLAC success [149 (39.1%) vs. 22 (69%), odds ratio (OR) 95% confidence interval (CI) 0.29 (0.13-0.64), p = 0.001]. The rate of induction of labor was higher in the TOLAC failure group [120 (31.5%) vs. 17 (53%), OR 95% CI 0.40 (0.19-0.83), p = 0.013]. The rate of oxytocin administration was higher in the TOLAC failure group [94 (24.7%) vs. 15 (47%) OR (95% CI) 0.37 (0.17-0.77), p = 0.006]. The duration of rupture of membranes was negatively associated with TOLAC success. Neonatal and maternal adverse outcomes did not differ between study groups. In multivariable logistic regression analysis, only the duration of rupture of membranes and modified Bishop score < 4 were independently associated with TOLAC success [adjusted OR (95% CI) 0.98 (0.96-0.99), p = 0.027 and 0.40 (0.16-0.97), p = 0.044]. CONCLUSION: TOLAC among GMP has a very-high success rate. Shortening the duration of ruptured membranes is a modifiable factor that may be associated with increased TOLAC success rates.

Sonographic fetal head circumference is associated with trial of labor after cesarean section success.

PURPOSE: The purpose is to study the association of the fetal sonographic head circumference (SHC) with trial of labor after cesarean (TOLAC) success rate, among women with no prior vaginal deliveries. METHODS: A retrospective case-control study including all women with no prior vaginal delivery undergoing TOLAC during 3/2011-6/2020 with a sonographic estimated fetal weight within one week from delivery. TOLAC success and failure groups were compared. RESULTS: Of 1232 included women, 948 (76.9%) delivered vaginally. The mean fetal SHC was smaller in the TOLAC success group (330 ± 10 vs. 333 ± 11 mm, p < 0.001). In a multivariate regression analysis, predelivery BMI, hypertensive disorders, gestational age at prior CD, SHC and epidural analgesia administration were independently associated with TOLAC success. A ROC analysis of the multivariable model composed of the factors found independently associated with TOLAC success, excluding SHC, yielded an area under curve of 0.659 (95% CI 0.622-0.697) compared with 0.668 (95% CI 0.630-0.705) with SHC included. CONCLUSION: Smaller SHC is independently associated with TOLAC success among women that did not deliver vaginally before, and has additive clinical value for the prediction of TOLAC success when combined with non-sonographic factors.

Sonographic fetal head circumference and the risk of obstetric anal sphincter injury following vaginal delivery.

INTRODUCTION: High birth weight is strongly associated with OASIS; nevertheless, it has not been determined which biometric characteristics most affect OASIS occurrence. We aimed to evaluate the association of estimated fetal head circumference with OASIS occurrence among primiparous women delivering by unassisted vaginal delivery. METHODS: A retrospective study included all primiparous women who delivered at term by spontaneous vaginal delivery from 2011-2019. Women were allocated to two groups: (1) those who experienced OASIS and (2) those who did not experience OASIS. Risk factors for OASIS were analyzed. RESULTS: Overall, 7646 women were included in the study cohort. Of those, 119/7646 (1.6%; 95% CI, 1.3-1.9%) experienced OASIS. Sonographic head circumference and birth weight did not vary between groups. Prolonged second stage was more common in the OASIS group [23 (19%) vs. 986 (13.3%), 1.58 OR (95% CI 1.003-2.51, p = 0.04)]. Absence of epidural analgesia was more common in the OASIS group [30 (25%) vs. 1197 (15.9%), 1.8 OR (95% CI 1.1-2.7, p = 0.006)]. On multivariate logistic regression analysis, the lack of epidural analgesia and duration of second stage of labor were both independently positively associated with OASIS [adjusted OR 2.67 (95% CI 1.55-4.62), p < 0.001, adjusted OR 1.23 (95% CI 1.11-1.43), p < 0.001, respectively)]. CONCLUSION: Sonographic head circumference and birth weight are not associated with OASIS occurrence among primiparous women delivering by an unassisted vaginal delivery. Prolonged second stage and the use of epidural analgesia are modifiable risk factors among these women.

Low volume forceps practice and anal sphincter injury rate.

PURPOSE: While the increased rates of high degree perineal tears were previously associated with the use of forceps, in the current era of low volume of forceps practice, factors associated with the occurrence of this potential complication remain understudied. We aim to evaluate factors associated with obstetric anal sphincter injury (OASIS) in obstetric units with a low volume forceps practice. METHODS: A retrospective cohort study was conducted at two tertiary medical centers. All singleton pregnancies delivered by forceps extraction between 2011 and 2019 were analyzed. Women who experienced anal sphincter injury were compared to those who did not. RESULTS: The study cohort included 764 forceps deliveries. There were 19 (2.5%) cases of OASIS. Women with anal sphincter injury had higher rates of gestational diabetes mellitus (21% vs. 5.6%, OR [95% CI] 4.46 (1.41-14.04), p = 0.02). Birth weights and the rate of macrosomia did not differ between groups. Induction of labor was more common among the OASIS group (68% vs. 41.7%, OR [95% CI] 3.0 (1.1-8.0), p = 0.02). Sequential use of forceps (after failed vacuum attempt) was associated with OASIS (8 (42%) vs. 76 (10.2%), OR [95% CI] 6.4 (2.5-16.4), p < 0.001). In a multivariate logistic regression, sequential forceps was the only factor independently associated with OASIS (OR [95% CI] 4.7 (1.3-18.2), p = 0.02). CONCLUSIONS: Rate of OASIS was relatively low in the current cohort. Sequential use of forceps was found to be the most important determinant in OASIS occurrence.

Length of the second stage of labor among women achieving vaginal birth after cesarean.

OBJECTIVE: To characterize the length of the second stage of labor among women completing a first vaginal birth after a cesarean (VBAC), according to the stage of labor during primary cesarean delivery (CD). METHODS: A retrospective cohort study of VBACs between 2011 and 2020. Study groups were divided as follows: CD not in labor, CD in the first stage of labor, and CD in the second stage of labor. The primary outcome was the length of the second stage. RESULTS: A total of 1310 VBACs were included. The timing of the primary CD was not associated with the duration of the second stage. The median second stage of duration of VBACs with previous first stage CD versus previous CD not in labor was 81 versus 106 min, respectively (P = 0.050). In multivariable linear regression, maternal age, birth weight, and epidural were independently associated with second-stage length. Maternal and neonatal outcomes did not differ between study groups and were not affected by the second-stage length. CONCLUSION: When stratified according to the labor stage of the primary CD, second-stage duration among women completing VBACs was not associated with labor stage at the primary CD. Extremes of the second-stage duration were not associated with increased morbidity.

Prediction of vaginal birth after cesarean for labor dystocia by sonographic estimated fetal weight.

OBJECTIVE: To estimate the association of the weight difference between the index trial of labor after cesarean (TOLAC) sonographic estimated fetal weight (sEFW) and prior delivery birth weight with TOLAC success rate among women with previous labor dystocia and no prior vaginal delivery. METHODS: A retrospective cohort study including all women with prior cesarean for labor dystocia and no prior vaginal delivery undergoing TOLAC during between March 2011 and June 2020 with a sEFW within 1 week from delivery. RESULTS: Overall, 168 women were included, of those 107 (63.7%) successfully delivered vaginally. The mean sEFW and mean birth weight were lower in the TOLAC success group (P = 0.010 and P = 0.013, respectively). The rate of higher sEFW in the current delivery compared with the previous delivery did not differ between study groups. The rate of higher TOLAC birth weight was lower in the TOLAC success group (odds ratio 0.30; 95% confidence interval 0.15-0.58). In multivariable regression analysis, maternal age older than 30 years, induction of labor, and higher birth weight were independently negatively associated with TOLAC success (adjusted odds ratio [95% confidence interval]: 0.27 [0.10-0.70], 0.27 [0.08-0.90], and 0.43 [0.19-0.94]; P = 0.008, P = 0.034, and P = 0.035, respectively). CONCLUSIONS: sEFW characteristics did not predict the success or failure of TOLAC among women with prior labor dystocia and no previous vaginal delivery.

Prediction of successful vaginal birth after cesarean in women with diabetic disorders and no prior vaginal delivery.

OBJECTIVE: To study the factors associated with successful trial of labor after cesarean (TOLAC) among women with diabetes and no prior vaginal delivery and compare with TOLAC in nondiabetic women. METHODS: A retrospective study including all women undergoing TOLAC who had no prior vaginal delivery between March 2011 and June 2020 at Sheba Medical Center. Women with diabetic disorders were compared with those without. Multivariate regression analysis was performed to identify factors independently associated with TOLAC success. RESULTS: Of 2144 deliveries with TOLAC, 163 (7.6%) were to women with a diabetic disorder. TOLAC success rate was comparable between diabetic and nondiabetic women (124 [76.1%] vs 1513 [76.4%], respectively; P = 0.931). Uterine rupture rate was 1.1% (23 out of 2144). Among women with diabetes the uterine rupture rate was 0.6% (1 out of 163) and did not differ between the success or fail TOLAC groups. Multivariate logistic regression showed that epidural anesthesia and cervical effacement were the only independent factors associated with TOLAC success in women with diabetes (adjusted OR 3.32; 95% CI, 1.31-8.69, P = 0.011 and aOR 1.04; 95% CI, 1.01-1.07, P = 0.007, respectively). CONCLUSION: TOLAC in women with diabetes with no prior vaginal delivery has a high success rate. Epidural analgesia is the only modifiable independent predictor of TOLAC success.

Implementation of machine learning models for the prediction of vaginal birth after cesarean delivery.

OBJECTIVE: Accurate prediction of vaginal birth after cesarean is crucial for selecting women suitable for a trial of labor after cesarean (TOLAC). We sought to develop a machine learning (ML) model for prediction of TOLAC success and to compare its accuracy with that of the MFMU model. METHODS: All consecutive singleton TOLAC deliveries from a tertiary academic medical center between February 2017 and December 2018 were included. We developed models using the following ML algorithms: random forest (RF), regularized regression (GLM), and eXtreme gradient-boosted decision trees (XGBoost). For developing the ML models, we disaggregated BMI into height and weight. Similarly, we disaggregated prior arrest of progression into prior arrest of dilatation and prior arrest of descent. We applied a nested cross-validation approach, using 100 random splits of the data to training (80%, 792 samples) and testing sets (20%, 197 samples). We used the area under the precision-recall curve (AUC-PR) as a measure of accuracy. RESULTS: Nine hundred and eighty-nine TOLAC deliveries were included in the analysis with an observed TOLAC success rate of 85.6%. The AUC-PR in the RF, XGBoost and GLM models were 0.351±0.028, 0.350±0.028 and 0.336±0.024, respectively, compared to 0.325±0.067 for the MFMU-C. The algorithms performed significantly better than the MFMU-C (p-values = .0002, .0004, .0393 for RF, XGBoost, GLM respectively). In the XGBoost model, eight variables were sufficient for accurate prediction. In all ML models, previous vaginal delivery and height were among the three most important predictors of TOLAC success. Prior arrest of descent contributed to prediction more than prior arrest of dilatation, maternal height contributed more than weight. CONCLUSION: All ML models performed significantly better than the MFMU-C. In the XGBoost model, eight variables were sufficient for accurate prediction. Prior arrest of descent and maternal height contribute to prediction more than prior arrest of dilation and maternal weight.