Resumen Objetivos: determinar la asociación entre postura de parto vertical y desgarros perineales grado II o más en mujeres atendidas bajo el modelo humanizado. Métodos: se estudiaron 715 registros clínicos de partos humanizados atendidos entre 2016 y 2022 en Viña del Mar, Chile, mediante análisis bivariado y regresión logística binaria. Resultados: el 64.1% de las mujeres presentó lesiones perineales, principalmente de bajo grado (51.2%). Los desgarros de segundo grado o más representaron un 12.2% (mayoritariamente grado II), siendo muy escasos los desgarros grado III (0.7%) y nulos los desgarros grado IV. Las posturas verticales, en comparación a las horizontales, se asociaron significativamente a la presencia de desgarros grado II o más (p=0.02), incluso luego de ajustar por variables maternas y neonatales (OR=2.31, IC95%=1.11-4.81). De estas últimas, la paridad y la talla del recién nacido fueron los factores que más se asociaron con este tipo de lesiones. Conclusión: los partos humanizados en general presentan una menor frecuencia y gravedad de lesiones perineales que lo reportado en atenciones tradicionales, no obstante, las posturas verticales, en comparación a las horizontales, se asociaron significativamente a la presencia de desgarros grado II o más. Objetivos humanizado Métodos 71 201 202 Mar Chile binaria Resultados 641 64 1 64.1 51.2%. 512 51.2% . 51 2 (51.2%) 122 12 12.2 mayoritariamente II, , II) 0.7% 07 0 7 (0.7% IV verticales horizontales p=0.02, p002 p p=0.02 02 (p=0.02) OR=2.31, OR231 OR 31 (OR=2.31 IC95%=1.114.81. IC95111481 IC IC95%=1.11 4.81 IC95 11 4 81 IC95%=1.11-4.81) últimas Conclusión tradicionales obstante 20 6 64. 51.2 5 (51.2% 12. 0.7 (0.7 p00 p=0.0 (p=0.02 OR=2.31 OR23 3 (OR=2.3 114 IC95%=1.114.81 IC9511148 IC95111 IC95%=1.1 481 4.8 IC9 8 IC95%=1.11-4.81 51. (51.2 0. (0. p0 p=0. (p=0.0 OR=2.3 OR2 (OR=2. IC95%=1.114.8 IC951114 IC9511 IC95%=1. 48 4. IC95%=1.11-4.8 (51. (0 p=0 (p=0. OR=2. (OR=2 IC95%=1.114. IC951 IC95%=1 IC95%=1.11-4. (51 ( p= (p=0 OR=2 (OR= IC95%=1.114 IC95%= IC95%=1.11-4 (5 (p= OR= (OR IC95% IC95%=1.11- (p

Abstract Objectives: to determine the association between vertical childbirth posture and grade II or higher perineal tears in women attended under a humanized model. Methods: 715 clinical records of humanized deliveries attended between 2016 and 2022 in Viña del Mar, Chile, were studied using bivariate analysis and binary logistic regression. Results: 64.1% of the women presented perineal lesions, mainly low grade (51.2%). Second degree tears or more represented 12.2% (mostly grade II), with very few grade III tears (0.7%) and zero grade IV tears. Vertical postures, compared to horizontal ones, were significantly associated with the presence of grade II tears or more (p=0.02), even after adjusting for maternal and neonatal variables (OR=2.31, CI95%=1.11-4.81). Of the latter, parity and size of the newborn were the factors most associated with this type of injury. Conclusion: humanized childbirths in general present less frequency and severity of perineal injuries than what is reported in traditional care; however, upright postures, compared to horizontal ones, were significantly associated with the presence of grade II or higher tears. Objectives model Methods 71 201 202 Mar Chile regression Results 641 64 1 64.1 lesions 51.2%. 512 51.2% . 51 2 (51.2%) 122 12 12.2 mostly II, , II) 0.7% 07 0 7 (0.7% postures ones p=0.02, p002 p p=0.02 02 (p=0.02) OR=2.31, OR231 OR 31 (OR=2.31 CI95%=1.114.81. CI95111481 CI CI95%=1.11 4.81 CI95 11 4 81 CI95%=1.11-4.81) latter injury Conclusion care however 20 6 64. 51.2 5 (51.2% 12. 0.7 (0.7 p00 p=0.0 (p=0.02 OR=2.31 OR23 3 (OR=2.3 114 CI95%=1.114.81 CI9511148 CI95111 CI95%=1.1 481 4.8 CI9 8 CI95%=1.11-4.81 51. (51.2 0. (0. p0 p=0. (p=0.0 OR=2.3 OR2 (OR=2. CI95%=1.114.8 CI951114 CI9511 CI95%=1. 48 4. CI95%=1.11-4.8 (51. (0 p=0 (p=0. OR=2. (OR=2 CI95%=1.114. CI951 CI95%=1 CI95%=1.11-4. (51 ( p= (p=0 OR=2 (OR= CI95%=1.114 CI95%= CI95%=1.11-4 (5 (p= OR= (OR CI95% CI95%=1.11- (p