Mark P Hehir1,2, Zachary Rubeo3, Karen Flood3, Anne H Mardy3, Colm O'Herlihy4, Peter C Boylan4, Mary E D'Alton3. 1. New York Presbyterian Hospital, Columbia University College of Physicians and Surgeons, New York, NY, USA. mh3616@cumc.columbia.edu. 2. National Maternity Hospital, Holles Street, Dublin 2, Ireland. mh3616@cumc.columbia.edu. 3. New York Presbyterian Hospital, Columbia University College of Physicians and Surgeons, New York, NY, USA. 4. National Maternity Hospital, Holles Street, Dublin 2, Ireland.
Abstract
INTRODUCTION AND HYPOTHESIS: Shoulder dystocia is an obstetric emergency that occurs in 0.2-3% of all cephalic vaginal deliveries. We hypothesized that because of the difficult nature of deliveries complicated by shoulder dystocia, the condition may be associated with anal sphincter injury. We sought to identify risk factors for obstetric anal sphincter injury in women with shoulder dystocia. METHODS: This retrospective analysis included all cases of shoulder dystocia from 2007 to 2011 at two large tertiary referral centers, in the USA and Ireland. Details of maternal demographics, intrapartum characteristics, and delivery outcomes in cases of shoulder dystocia were analyzed. Univariate and multivariate analyses were used to describe the association between shoulder dystocia and anal sphincter injury. RESULTS: There were 685 cases of shoulder dystocia, and the rate of shoulder dystocia was similar at both institutions. The incidence of anal sphincter injury was 8.8% (60 out of 685). The rate was 14% (45 out of 324) in nulliparas and 4.2% (15 out of 361) in multiparas. Women with sphincter injury were more likely to be nulliparous (75% [45 out of 60] vs 45% [279 out of 625]; p < 0.0001), have had an operative vaginal delivery (50% [30 out of 60] vs 36% [226 out of 625]; p = 0.03) and require internal maneuvers (50% [30 out of 60] vs 32% [198 out of 625], p = 0.004) than those with an intact sphincter. On multivariate regression analysis, these predictors of sphincter injury remained significant when adjusted for other risk factors. Episiotomy was negatively associated with sphincter injury on multivariate regression analysis. CONCLUSIONS: In a retrospective cohort of 685 women with shoulder dystocia, the risk of anal sphincter injury is 9%. Risk factors include nulliparity, operative vaginal delivery, and use of internal maneuvers, whereas episiotomy was found to have a protective effect against anal sphincter injury during cases of shoulder dystocia.
INTRODUCTION AND HYPOTHESIS: Shoulder dystocia is an obstetric emergency that occurs in 0.2-3% of all cephalic vaginal deliveries. We hypothesized that because of the difficult nature of deliveries complicated by shoulder dystocia, the condition may be associated with anal sphincter injury. We sought to identify risk factors for obstetric anal sphincter injury in women with shoulder dystocia. METHODS: This retrospective analysis included all cases of shoulder dystocia from 2007 to 2011 at two large tertiary referral centers, in the USA and Ireland. Details of maternal demographics, intrapartum characteristics, and delivery outcomes in cases of shoulder dystocia were analyzed. Univariate and multivariate analyses were used to describe the association between shoulder dystocia and anal sphincter injury. RESULTS: There were 685 cases of shoulder dystocia, and the rate of shoulder dystocia was similar at both institutions. The incidence of anal sphincter injury was 8.8% (60 out of 685). The rate was 14% (45 out of 324) in nulliparas and 4.2% (15 out of 361) in multiparas. Women with sphincter injury were more likely to be nulliparous (75% [45 out of 60] vs 45% [279 out of 625]; p < 0.0001), have had an operative vaginal delivery (50% [30 out of 60] vs 36% [226 out of 625]; p = 0.03) and require internal maneuvers (50% [30 out of 60] vs 32% [198 out of 625], p = 0.004) than those with an intact sphincter. On multivariate regression analysis, these predictors of sphincter injury remained significant when adjusted for other risk factors. Episiotomy was negatively associated with sphincter injury on multivariate regression analysis. CONCLUSIONS: In a retrospective cohort of 685 women with shoulder dystocia, the risk of anal sphincter injury is 9%. Risk factors include nulliparity, operative vaginal delivery, and use of internal maneuvers, whereas episiotomy was found to have a protective effect against anal sphincter injury during cases of shoulder dystocia.
Authors: Mark P Hehir; Fiona R Reidy; Michael N Wilkinson; Rhona Mahony Journal: Eur J Obstet Gynecol Reprod Biol Date: 2013-08-14 Impact factor: 2.435
Authors: Melanie R L Meister; Alison G Cahill; Shayna N Conner; Candice L Woolfolk; Jerry L Lowder Journal: Am J Obstet Gynecol Date: 2016-02-20 Impact factor: 8.661
Authors: Alexander M Friedman; Cande V Ananth; Eri Prendergast; Mary E D'Alton; Jason D Wright Journal: Obstet Gynecol Date: 2015-04 Impact factor: 7.661