Factores predictores del éxito del parto vaginal posterior a cesárea

Objetivo : Determinar los predictores del éxito del parto vaginal posterior a cesárea segmentaria transversal primaria por causa no recurrente. Diseño : Estudio de casos y controles. Institución: Hospital Central "Dr. Urquinaona", Maracaibo, Venezuela. Métodos : Gestantes con inicio espontáneo del trabajo de parto y antecedentes de cesárea con incisión transversal en el segmento inferior por causa no iterativa. La prueba de parto fue considerada exitosa si terminaba en parto vaginal. Principales medidas de estudio : Edad materna, paridad, frecuencia de trabajo de parto previo a la cesárea anterior, edad gestacional al momento del parto, estación de la presentación cefálica fetal al ingreso y peso fetal. Resultados : Se seleccionó 126 gestantes, de las cuales 85 (67,4%) tuvieron pruebas exitosas (parto vaginal), mientras que 41 (32,5%) tuvieron prueba fallida. No se encontraron diferencias en las características generales entre los grupos (p = ns). El análisis univariante mostró que el peso fetal igual o menor de 3,500 gramos, la estación de la presentación cefálica fetal fija o encajada y la edad gestacional menor de 40 semanas fueron predictores significativos del resultado exitoso de la prueba de parto (p < 0,05). El análisis de regresión logística demostró que el peso fetal igual o mayor de 3,500 gramos (p = 0,04) y la estación de la presentación cefálica fetal flotante insinuada (p = 0,03) conservaron importancia como predictores. Conclusión : Los predictores para una prueba exitosa de parto vaginal posterior a cesárea fueron peso fetal menor o igual a 3,500 gramos y la estación de la presentación cefálica fetal fija o encajada.

Objective : To determine predictors of successful vaginal delivery following primary transverse segmental cesarean section for non-recurring cause. Design : Casecontrol study. Institution: Hospital Central "Dr. Urquinaona", Maracaibo, Venezuela. Methods : Pregnant women with spontaneous onset of labor and history of cesarean section with transverse incision in the lower segment for non-recurrent cause. The trial of labor was considered successful if it ended in vaginal delivery. Main study measures : Maternal age, parity, frequency of labor prior to previous cesarean section, gestational age at delivery, station of fetal cephalic presentation at admission, and fetal weight. Results : A total of 126 pregnant women were selected, of whom 85 (67.4%) had successful trials (vaginal delivery), while 41 (32.5%) had a failed trial. No differences in general characteristics were found between groups (p = ns). Univariate analysis showed that fetal weight equal to or less than 3,500 grams, station of fixed or engaged fetal cephalic presentation, and gestational age less than 40 weeks were significant predictors of successful trial of labor outcome (p < 0.05). Logistic regression analysis showed that fetal weight equal to or greater than 3,500 grams (p = 0.04) and station of floating insinuated fetal cephalic presentation (p = 0.03) retained significance as predictors. Conclusion : Predictors for a successful trial of vaginal delivery following cesarean section were fetal weight less than or equal to 3,500 grams and station of fixed or engaged fetal cephalic presentation.

Risk score for failed trial of vaginal birth after a previous cesarean section including data of labor course.

AIM: There is much discussion about the advantages and disadvantages of a trial of labor after cesarean (TOLAC). Some data suggest the greater the likelihood of success, the lower the risks of TOLAC. Our goal was to identify clinical and demographic variables associated with a failed TOLAC, available at admission for spontaneous labor and until 3 h later, with the aim of building two scores for risk of failed TOLAC. METHODS: This is a nested case-control study with live births to women with one previous cesarean, in a public Brazilian teaching hospital. Preterm, induction, noncephalic presentations, twins, fetal malformations were excluded. Cases were failed TOLAC, and controls, the successful TOLAC. It was accessed the association of the cases with 20 variables (P < 0.05). Associated variables were tested in multivariate analysis to build the scores, which were internally validated. RESULTS: We included 260 TOLAC, 42 cases and 218 controls. We found 11 variables associated with failed TOLAC. In the score to be applied at admission, we included hypertension, fundal height, previous vaginal birth and dilatation at admission. In the second score hypertension, fundal height at admission, membrane status and difference in dilatation 3 h after admission. Both scores presented good performance in the receiver-operator curve (areas under curve: 0.73 and 0.84, respectively). Both scores were translated into nomograms for clinical use. CONCLUSION: Two scores were built for risk of failed TOLAC, to be applied at admission and 3 h later. We believe that choosing the more favorable cases makes risks of TOLAC lower.

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

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. METHODS: Retrospective cohort study involving women with previous history of a previous segmental cesarean section, single pregnancy ≥37 weeks and cephalic presentation. 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. RESULTS: The proportion of successful delivery in pregnant women with a previous cesarean section and indication of vaginal delivery was 85.64%. The observed proportion of birth for each decile predicted in the Grobman model was less than 15%, except for the 91-100% decile, where it was 64.09%; the area under the curve was 0.95. 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 0.94. CONCLUSIONS: 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.

INTRODUCCIÓN: Una estrategia de reducción del número de cesáreas es permitir el parto vaginal después de cesárea. OBJETIVO: Validar dos modelos predictivos, Metz y Grobman, para el parto vaginal exitoso después de una cesárea. MÉTODOS: Estudio de cohorte retrospectivo con mujeres con antecedente de una cesárea segmentaria previa, embarazo único ≥37 semanas y presentación cefálica . Se determinó la proporción de parto vaginal en todas las gestantes y se comparó con aquellas con parto exitoso después de cesárea, se elaboró los modelos y se determinó la capacidad predictiva de ellos mediante curva-receptor-operador. RESULTADOS: La proporción de parto exitoso en gestantes con cesárea previa e indicación de parto vaginal fue 85.64%. La proporción de parto observado para cada decil predicho en el modelo de Grobman fue inferior al 15%, excepto para el decil 91-100%, en el que fue 64.09%, el área bajo la curva fue 0.95. Para el modelo de Metz, la proporción de parto exitoso real fue menor a lo predicho en puntajes entre 4-14 y dentro de lo esperado para puntaje entre 15-23, con un área bajo la curva de 0.94. CONCLUSIONES: La tasa de parto vaginal después de cesárea fue menor a lo esperado de acuerdo a los modelos predictivos de Grobman y Metz. La implementación de estos modelos en forma prospectiva puede llevar una mayor tasa de parto exitoso.

Validation of a predictive model for successful vaginal birth after cesarean section / Validación de modelos predictivos para parto vaginal exitoso después de cesárea

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. Methods: Retrospective cohort study involving women with previous history of a previous segmental cesarean section, single pregnancy ≥37 weeks and cephalic presentation. 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. Results: The proportion of successful delivery in pregnant women with a previous cesarean section and indication of vaginal delivery was 85.64%. The observed proportion of birth for each decile predicted in the Grobman model was less than 15%, except for the 91-100% decile, where it was 64.09%; the area under the curve was 0.95. 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 0.94. Conclusions: 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.

Resumen Introducción: Una estrategia de reducción del número de cesáreas es permitir el parto vaginal después de cesárea. Objetivo: Validar dos modelos predictivos, Metz y Grobman, para el parto vaginal exitoso después de una cesárea. Métodos: Estudio de cohorte retrospectivo con mujeres con antecedente de una cesárea segmentaria previa, embarazo único ≥37 semanas y presentación cefálica . Se determinó la proporción de parto vaginal en todas las gestantes y se comparó con aquellas con parto exitoso después de cesárea, se elaboró los modelos y se determinó la capacidad predictiva de ellos mediante curva-receptor-operador. Resultados: La proporción de parto exitoso en gestantes con cesárea previa e indicación de parto vaginal fue 85.64%. La proporción de parto observado para cada decil predicho en el modelo de Grobman fue inferior al 15%, excepto para el decil 91-100%, en el que fue 64.09%, el área bajo la curva fue 0.95. Para el modelo de Metz, la proporción de parto exitoso real fue menor a lo predicho en puntajes entre 4-14 y dentro de lo esperado para puntaje entre 15-23, con un área bajo la curva de 0.94. Conclusiones: La tasa de parto vaginal después de cesárea fue menor a lo esperado de acuerdo a los modelos predictivos de Grobman y Metz. La implementación de estos modelos en forma prospectiva puede llevar una mayor tasa de parto exitoso.

Elective repeat cesarean delivery in women eligible for trial of labor in Brazil.

OBJECTIVE: To assess the hospital, maternal, and obstetric characteristics associated with elective repeat cesarean delivery (ERCD) among women eligible for trial of labor after cesarean (TOLAC) delivery in Brazil. METHODS: The present data were retrieved from the Birth in Brazil study, a national hospital-based cohort study conducted during 2011-2012. Data were collected from medical records and by interview. Univariate and hierarchical multiple logistic regression analyses were performed to analyze factors associated with ERCD among women with a previous cesarean delivery who were eligible for TOLAC. RESULTS: Among 2295 women considered eligible for TOLAC, 1516 (66.1%) had an ERCD; the overall cesarean delivery rate was 79.4%. In the private sector, almost all deliveries (95.3%) were performed by ERCD. In the public sector, ERCD was associated with socioeconomic (more years of schooling), obstetric (women's preference, no previous vaginal delivery, macrosomia), and hospital (mixed hospital, location in noncapital city, fewer than 1500 deliveries per year) characteristics. CONCLUSION: The ERCD rate in Brazil was high even in a low-risk group, indicating that nonclinical factors may be driving the decision for cesarean delivery. Efforts aiming to reduce cesarean deliveries in Brazil should target women with a previous cesarean delivery.

Repeat cesarean section in subsequent gestation of women from a birth cohort in Brazil.

BACKGROUND: The current literature indicates increasing concern regarding the number of safe cesarean sections which a woman can undergo, mainly in face of the high cesarean section rates, which are growing in Brazil and worldwide. Aimed to describe the prevalence and associated factors of repeat cesarean section in a cohort of Brazilian women who had a cesarean section in the first birth. METHODS: This is a prospective cohort study using data from the 2004 Pelotas Birth Cohort. The sample included 480 women who had their first delivery in 2004, regardless of the form of delivery, and who had a second delivery identified in the cohort's follow-ups (in 2005, 2006, 2008, and 2010). Descriptive, bivariate and multivariate analyses using Poisson regression with robust error variance were carried out. RESULTS: Among the women who underwent a cesarean section in their first delivery (49.47%), 87.44% had a second surgical delivery. The risk factors for repeat cesarean section included ages 21-34 (PR 1.67, CI 95% 1.07-2.60), not being seen by SUS (Public Healthcare System) in 2004 (PR 2.27, CI 95% 1.44-3.60), and the number of prenatal medical visits, i.e., women with ten or more visits were at 2.33 times higher risk (CI 95% 1.10-4.96) compared to those who had five or fewer visits. CONCLUSIONS: The proportion of cesarean sections both in the first and in the subsequent delivery is quite high. This high rate may compromise the reproductive future of the women who undergo consecutive cesarean sections with possible consequent complications and changes in care policies for pregnant women should be implemented.

Cesarean sections in Brazil: will they ever stop increasing? / Cesáreas en el Brasil: ¿dejarán de aumentar alguna vez?

OBJECTIVE: To describe trends, geographic distribution, and risk factors for cesarean deliveries in Brazil in 2000-2011, and to determine if efforts to curtail rates have had a measurable impact. METHODS: This was an observational study using nationwide information from the Department of Informatics of the Unified Health System (DATASUS). Individual level analyses were based on data regarding maternal education, age, parity, and skin color. Ecological analyses at the level of 431 health districts investigated the relationships with health facility density and poverty level. RESULTS: Cesarean rates increased markedly, from 37.9% in 2000 to 53.9% in 2011. Preliminary results from 2012 showed a rate of 55.8%, with the richest geographic areas showing the highest rates. Rates at the municipal level varied from 9%-96%. Cesareans were more common in women with higher education, white skin color, older age, and in primi- paras. In the ecological analyses, the number of health facilities per 1 000 population was strongly and positively correlated with cesarean rates, with an increase of 16.1 percentage points (95% Confidence Interval [95%CI] = 4.3-17.8) for each facility. An increase of 1 percentage point in the poverty rate was associated with a decline of 0.5 percentage point in cesarean rates (95%CI = 0.5-0.6). CONCLUSIONS: The strong associations with maternal education and health facility density suggest that the vast majority of cesareans are not medically indicated. A number of policies and programs have been launched to counteract this trend, but have had virtually no impact.

OBJETIVO: Describir las tendencias, la distribución geográfica, y los factores de riesgo de parto por cesárea en el Brasil durante el período del 2000 al 2011, y determinar si las iniciativas dirigidas a reducir las tasas de cesáreas han tenido una repercusión cuantificable. MÉTODOS: Se trata de un estudio de observación que utilizó información a escala nacional del Departamento de Informática del Sistema Unificado de Salud (DATASUS). Los análisis a nivel individual se basaron en datos sobre el nivel de formación materna, la edad, la paridad y el color de la piel. Se investigaron las relaciones con la densidad de establecimientos de salud y el nivel de pobreza mediante análisis ecológicos a nivel de 431 distritos de salud. RESULTADOS: Las tasas de cesáreas aumentaron notablemente, de 37,9% en el 2000 a 53,9% en el 2011. Los resultados preliminares del 2012 mostraron una tasa de 55,8%, con tasas más elevadas en las zonas geográficas más ricas. Las tasas a escala municipal variaron de 9 a 96%. Los partos por cesárea fueron más frecuentes en las mujeres blancas, en las que tenían un mayor nivel de formación, en las de mayor edad y en las primíparas. En los análisis ecológicos, el número de establecimientos de salud por 1 000 habitantes se correlacionó intensa y positivamente con la tasa de cesáreas, con un incremento de 16,1 puntos porcentuales (intervalo de confianza (IC) de 95% = 4,3-17,8) para cada establecimiento. Un aumento de un punto porcentual en la tasa de pobreza se asociaba con una disminución de medio punto porcentual en la tasa de cesáreas (IC de 95% = 0,5-0,6). CONCLUSIONES: Las intensas asociaciones con el nivel de formación materna y la densidad de establecimientos de salud indican que la mayor parte de las cesáreas no están indicadas médicamente. Se han puesto en marcha diversos programas y políticas dirigidos a contrarrestar esta tendencia, pero prácticamente no han tenido ninguna repercusión.

Factors associated with vaginal birth after previous cesarean section in Brazilian women / Factores relacionados con el parto vaginal en mujeres brasileñas con cesárea anterior

OBJETIVO: Determinar qué factores se asocian con el parto vaginal en mujeres que han tenido una cesárea. MÉTODOS: Un estudio anidado de casos y testigos se llevó a cabo en forma de un análisis de datos secundarios procedentes de un estudio de cohorte original, retrospectivo y de carácter poblacional en mujeres que tuvieron su primer hijo en 1985 en la ciudad de Campinas, São Paulo, Brasil, y que fueron entrevistadas 10 años más tarde, en 1995. La población estudiada se compuso de 1 352 mujeres cuyo primer hijo había nacido por cesárea y que también habían tenido como mínimo un parto posterior. El grupo de los casos (150 mujeres, o alrededor de 11% de la muestra) estuvo integrado por mujeres que tuvieron su segundo parto por la vía vaginal, y el grupo testigo se compuso de 1 202 mujeres que tuvieron su segundo parto por cesárea. Para cada uno de los posibles factores asociados se calcularon la razón de posibilidades y el intervalo de confianza de 95%. Se aplicó la prueba de tendencias de ji al cuadrado para analizar las variables categóricas. Se usó una regresión multifactorial incondicionada para estimar las razones de posibilidades ajustadas correspondientes a cada factor asociado. RESULTADOS: Los factores que mostraron una asociación estadísticamente significativa con el parto vaginal fueron un ingreso familiar mensual menor de cinco veces el salario mínimo mensual en el Brasil; depender del sistema nacional de salud brasileño para obtener atención sanitaria; poca edad materna; y una primera cesárea efectuada por presentación de nalgas o transversal, o por embarazo gemelar. Del grupo de mujeres que también tuvieron un segundo parto por cesárea, solamente 11% habían hecho un esfuerzo por tener un parto vaginal. CONCLUSIONES: El principal factor que determina el parto vaginal en mujeres que ya habían tenido una cesárea fue la presencia de factores sociales y económicos adversos

Objective. To identify factors associated with a vaginal second delivery in women who had one previous cesarean section. Methods. A nested case-control study was carried out as a secondary data analysis of an original retrospective, population-based cohort study of women who delivered their first child during 1985 in the city of Campinas, São Paulo, Brazil, and who were interviewed 10 years later in 1995. The study population consisted of 1 352 women who had their first delivery by cesarean section and who had also had at least one subsequent delivery. The group of cases (150 women, around 11% of the sample) consisted of women who had a vaginal second delivery, and the control group was made up of 1 202 women who had a cesarean section at second delivery. For each possible associated factor we calculated the odds ratio and 95% confidence interval. For ordered categorical variables the c2 test for trend was used. Unconditional multivariate regression analysis was used to estimate the adjusted odds ratio for each associated factor. Results. The factors significantly associated with vaginal delivery were monthly family income below 5-fold the Brazilian minimum monthly wage, reliance on the Brazilian nationalhealth system for healthcare, low maternal age, and first cesarean section indicated because of fetal breech or transverse presentation, or twin pregnancy. Among those women who also had a cesarean section at their second delivery, only 11% had undergone a trial of labor. Conclusions. The main determining factors for a vaginal second delivery in women with a previous cesarean section were unfavorable social and economic factors