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Language: English Spanish. A strategy for reducing the number of cesarean sections is to allow vaginal delivery after cesarean section. To validate two predictive models, Metz and Grobman, for successful vaginal delivery after a cesarean section. The proportion of vaginal delivery in all pregnant women was determined, and it was compared with those women with successful delivery after cesarean section. Then, there were elaborated the models, and their predictive capacity was determined by curve-receiver-operator.

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Language: English Spanish. A strategy for reducing the number of cesarean sections is to allow vaginal delivery after cesarean section. To validate two predictive models, Metz and Grobman, for successful vaginal delivery after a cesarean section. The proportion of vaginal delivery in all pregnant women was determined, and it was compared with those women with successful delivery after cesarean section.

Then, there were elaborated the models, and their predictive capacity was determined by curve-receiver-operator. The proportion of successful delivery in pregnant women with a previous cesarean section and indication of vaginal delivery was For the Metz model, the actual successful delivery rate was lower than predicted in scores between 4 and 14, and within expected for a score between 15 and 23; the area under the curve was 0.

The vaginal delivery rate after cesarean was lower than expected according to the predictive models of Grobman and Metz. The implementation of these models in a prospective way can lead to a higher rate of successful birth.

Cesarean section C-section is one of the most common surgical procedures performed in women, especially in developed countries. In , one in three women had a cesarean delivery 3. If this trend continues, by , it will be reached a rate of In Colombia, the current rate is The most common indications in the world for a primary cesarean include: stationary labor, altered or indeterminate fetal monitoring, anomalous fetal presentation and multiple gestation; corresponding the first two ones to more than half 6.

Up to At the beginning of the 20th century, there prevailed the concept of "once a cesarean, always a cesarean" 7 ; however, by , the American College of Obstetrics and Gynecology ACOG made recommendations on VBAC Vaginal Birth after Cesarean , considering it like an "Acceptable option", and even proposing in that "all women should be taken to VBAC in the absence of a medical or obstetric contraindication" 8.

In , Grobman 12 developed a prediction nomogram for the success of VBAC based on factors available at the first prenatal check-up: Maternal age, BMI, ethnic group, previous vaginal delivery, successful vaginal delivery after C-section the occurrence of a VBAC , and recurrence of the indication of primary cesarean section, all of which had an adequate predictive value. In , Grobman 13 included several factors at the time of admission to the delivery room: BMI at delivery, preeclampsia, gestational age at birth, cervical dilatation, effacement, stage and induction of labor, achieving a better performance of the model.

Recently, Metz et al. When comparing this model with those previously described by Grobman 12 factors at the first CPN and at the time of admission , the model developed by Metz et al. Currently, it is considered that the route of termination of a pregnancy, after cesarean delivery, is by vaginal delivery, but no predictive model is applied, and the decision depends mainly on the pelvic assessment and the Bishop index upon admission. For those reasons, the main objective of this study was to validate two predictive models, those by Metz and Grobman, for successful vaginal delivery after C-section VBAC in a pregnant population with previous C-section that enter to the Hospital for delivery; and to describe the maternal and fetal morbidity associated with vaginal delivery after C-section.

Retrospective cohort study, in women who were pregnant for 37 weeks or longer, with a previous C-section and who were admitted to HUV during the study period January to December ; there were included all pregnant women with a only previous cesarean procedure, pregnancy of 37 weeks or longer, and fetus in cephalic presentation at the time of defining the end of pregnancy; there were excluded patients with previous corporal C-section documented in the clinical history, previous uterine surgery myomectomy, uterine rupture or fetal death before the moment of defining the route of termination of pregnancy, as well as patients with inadequate pelvis.

In addition, the outcome variable was the mode of delivery : vaginal spontaneous or instrumented or C-section. In case of discrepancies, the database was confronted with the data collection formats. The sample size was determined according to the recommendation of Harrel 15 for validating a multivariate prediction model, according to which no less than 10 desired results are required successful delivery after C-section for each variable included in the prediction model.

In the case of the Grobman and Metz models that included antepartum and intra-partum variables, 13 variables were considered, which required successful vaginal births. Maternal and fetal morbidity are presented as absolute and relative frequencies.

To determine the predictive capacity of the Grobman model in the population of HUV, the predicted probability was determined by using the equation previously published by Grobman 13 for each one of the pregnant women. The predictive capacity of the model was established by calculating the area under the curve AUC of the operator receiver curve ROC. The area under the curve was determined non-parametrically in a non-parametric way , using the trapezoidal rule.

For the determination of the predictive capacity, it was constructed a logistic regression with the model variables, and the AUC of the operator receiver curve ROC was subsequently calculated. The area under the curve was determined non-parametrically, using the trapezoidal rule. During the years to , there were 29, births in the HUV, of which 8, were via C-section, for a proportion of C-sections of In the same period, there were pregnant women who met the inclusion criteria of the study and who did not present exclusion criteria, of which The characteristics of pregnant women for entering the study are presented in Table 1 and, according to the expected, there are statistically significant differences in most of them, except for maternal age, gestational age, proportion of patients with delivery before the initial C-section, and proportion of diabetes.

The number of deliveries was spontaneous and 3 instrumented , for a proportion of deliveries in pregnant women with a previous C-section of The majority of patients who had a delivery The median of the Bishop index RIQ at admission was 8 for pregnant women with C-section and 10 for those who completed delivery.

The characteristics of admission are presented in Table 2 , in which significant differences are observed in the proportion of labor after C-section and cervical dilatation at admission, being higher in both cases in the group of successful vaginal delivery.

Nine C-sections were performed due to imminence of uterine rupture; however, the uterus did not present solution of continuity in any of them. The number of births expected according to the probabilities predicted using the midpoint of each decile is , for an expected proportion of The number of births expected according to the predicted probabilities is , for an expected proportion of The sensitivity, specificity and likelihood ratios of the Grobman and Metz model are presented in Table 5.

Both models presented an area under the curve greater than 0. After selecting from the Grobman model only the variables that contribute to the logistic regression model for the pregnant women of the study, there persisted for our population the antecedent of delivery after C-section, effacement, station, dilatation at admission to the delivery service, and the presence of a hypertensive disorder.

The association between these variables and the opportunity of delivery is presented in Table 6. It was found in the present study that for both models, the observed probability of successful vaginal delivery after C-section was lower than predicted. Despite the above, the performance of both models was adequate, with areas under the curve higher than 0. Not all the variables of the Grobman model contributed to the prediction of VBAC in the validation of the model in our study; only some cervical changes persisted at admission dilatation, effacement and station , the antecedent of a birth after C-section and the presence of hypertensive disorder, which decreased the chance of VBAC; while for the Metz model, the only variable that persisted was Bishop's index at admission, which may be explained for being the cervical changes at the moment of pregnant woman's admission, a characteristic that determines the attempt of TOLAC.

This shows the adequate selection of pregnant women with a previous C-section undergoing TOLAC, based on cervical changes.

However, we believe that the application of a predictive model in clinical practice can potentially increase the overall success rate, which in our case was only The high rate of C-sections worldwide and nationally 3 , 5 , 18 , 19 , leads to the need for strategies in the search to reduce their number; and it is recognized that the most important thing is to avoid primary C-section; however, with the increase of these, iterative C-section has become one of the first causes of C-section; for this reason, the identification of factors or maternal characteristics that select pregnant candidates for VBAC is a strategy that can potentially contribute to this objective.

This and previous studies 12 , 13 show that cervical changes are the most important factors for the prediction of a successful birth after C-section; however, considering other variables such as the antecedent of a birth after C-section or the application of some predictive model can potentially lead to an increase in the number of pregnant women with a previous C-section in whom TOLAC is attempted.

One of the most important concerns for medical personnel is the risk of maternal complications such as uterine rupture and neonatal complications such as fetal death or neonatal asphyxia in patients undergoing delivery after C-section.

In the present study, there were found no significant differences for 5 years between the pregnant women taken to C-section or delivery; however, there were more cases of postpartum hemorrhage in cases of vaginal delivery 5.

With regard to newborns, no differences were found in the Apgar score at 5 minutes, or in the need for mechanical ventilation. Because of the retrospective nature, the decisions of delivery attempt depended on the criterion of the attending physician, and not on a previously standardized protocol, which may explain the low proportion of births Taking into account the similar performance between both models and the ease of application of the Metz model, we consider this one to be the most likely to be implemented in most obstetrical services, without the requirement of access to software or programs for determining the probability of successful vaginal delivery after C-section.

Funding: Universidad del Valle, Vice-rector office for research, Code En Colombia la tasa actual es Recientemente Metz et al. La morbilidad materna y fetal se presenta como frecuencias absolutas y relativas. La mayor parte de pacientes que tuvieron parto Se realizaron 9 2. La sensibilidad, especificidad y razones de verosimilitud del modelo de Grobman y de Metz se presentan en la Tabla 5.

RV: Razon de verosimilitud. National Center for Biotechnology Information , U. Journal List Colomb Med Cali v.

Colomb Med Cali. Published online Mar Author information Article notes Copyright and License information Disclaimer. Cali, Colombia. Corresponding author.

Javier E. E-mail: oc. Conflict of interest: Author not have any conflict of interest and the financing institutions did not influence in any way in the report of the results or their implications. Abstract Introduction: A strategy for reducing the number of cesarean sections is to allow vaginal delivery after cesarean section.

Objective: To validate two predictive models, Metz and Grobman, for successful vaginal delivery after a cesarean section. Results: The proportion of successful delivery in pregnant women with a previous cesarean section and indication of vaginal delivery was Conclusions: The vaginal delivery rate after cesarean was lower than expected according to the predictive models of Grobman and Metz.

Key words: Vaginal birth after cesarean, cohort study, validation study, repeat cesarean section, obstetric delivery, trial of labor, labor presentation, cervical dilatation. Introduction Cesarean section C-section is one of the most common surgical procedures performed in women, especially in developed countries.

Materials and Methods Retrospective cohort study, in women who were pregnant for 37 weeks or longer, with a previous C-section and who were admitted to HUV during the study period January to December ; there were included all pregnant women with a only previous cesarean procedure, pregnancy of 37 weeks or longer, and fetus in cephalic presentation at the time of defining the end of pregnancy; there were excluded patients with previous corporal C-section documented in the clinical history, previous uterine surgery myomectomy, uterine rupture or fetal death before the moment of defining the route of termination of pregnancy, as well as patients with inadequate pelvis.

Sample size and analysis The sample size was determined according to the recommendation of Harrel 15 for validating a multivariate prediction model, according to which no less than 10 desired results are required successful delivery after C-section for each variable included in the prediction model.

Results During the years to , there were 29, births in the HUV, of which 8, were via C-section, for a proportion of C-sections of Open in a separate window. Figure 1. Table 3 Predicted and observed probabilities of successful vaginal delivery in the HUV, according to the Grobman model. VBAC: Successful vaginal delivery. Table 4 Predicted and real probabilities of successful vaginal delivery in the HUV, according to the Metz model. Figure 2. Receiver-operator curve for prediction of successful vaginal delivery with the Grobman and Metz models.

Table 5 Performance of predictive models of successful vaginal delivery after C-section. Table 6 Opportunity of successful vaginal delivery in pregnant women. OR: odd ratio OR a : adjusted odd ratio. Table 7 Maternal complications, characteristics and neonatal complications, according to birth pathway. Discussion It was found in the present study that for both models, the observed probability of successful vaginal delivery after C-section was lower than predicted. Referencias 1.

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Validation of a predictive model for successful vaginal birth after cesarean section

Se evaluaron variables maternas, del parto, de resultado materno y neonatal. Rev Lat Am Enfermagem. Episiotomy: Early maternal and neonatal outcomes of selective versus routine use. Acta Obstet Ginecol Port. Resultados materno-fetales. Prog Obstet Ginecol. Rubio JA.

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