Official reprint from UpToDate®
www.uptodate.com ©2017 UpToDate®

Shoulder dystocia: Risk factors and planning delivery of high-risk pregnancies

John F Rodis, MD
Section Editor
Charles J Lockwood, MD, MHCM
Deputy Editor
Vanessa A Barss, MD, FACOG


A vaginal delivery is complicated by shoulder dystocia when, after delivery of the fetal head, additional obstetric maneuvers beyond gentle guidance are needed to enable delivery of the fetal shoulders. Shoulder dystocia is an obstetric emergency because it may result in life-threatening infant injuries, as well as less serious maternal injuries. It has been estimated that one newborn with hypoxic ischemic encephalopathy due to shoulder dystocia is born in every 22,000 term vaginal births [1].

This topic will discuss antepartum issues related to shoulder dystocia: risk factors for the disorder and planning delivery when these risk factors are identified before labor. However, since many shoulder dystocias occur in pregnancies without risk factors, clinicians should always be prepared for the occurrence of the disorder. Intrapartum issues, including pathophysiology, diagnosis, management, and outcome of shoulder dystocia are reviewed separately. (See "Shoulder dystocia: Intrapartum diagnosis, management, and outcome".)


The occurrence of shoulder dystocia cannot be accurately predicted by antenatal or intrapartum risk factors or imaging studies [2]. (See 'Risk factors' below and 'Pelvimetry and fetal biometry' below.)

Nevertheless, clinicians should be aware of risk factors for shoulder dystocia in order to discuss possible scheduled cesarean delivery with women at highest risk of occurrence. Since at least 50 percent of pregnancies complicated by shoulder dystocia have no identifiable risk factors, the predictive value of any one or combination of risk factors for shoulder dystocia is low (less than 10 percent) [3-5]. Therefore, all obstetric care providers should be able to (1) promptly recognize when gentle traction alone is inadequate for delivery of the shoulders and (2) proceed through an orderly sequence of maneuvers to deliver the neonate in a timely manner, with no or minimal maternal and fetal trauma.

It should be noted, however, that permanent birth injury, and even perinatal death, can occur in cases of shoulder dystocia that are appropriately identified and managed. Furthermore, neonatal brachial plexus palsy can occur in infants delivered by cesarean [6].


Subscribers log in here

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information or to purchase a personal subscription, click below on the option that best describes you:
Literature review current through: Jul 2017. | This topic last updated: Jul 28, 2017.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2017 UpToDate, Inc.
  1. Hoffman MK, Bailit JL, Branch DW, et al. A comparison of obstetric maneuvers for the acute management of shoulder dystocia. Obstet Gynecol 2011; 117:1272.
  2. Committee on Practice Bulletins—Obstetrics. Practice Bulletin No 178: Shoulder Dystocia. Obstet Gynecol 2017; 129:e123.
  3. Nesbitt TS, Gilbert WM, Herrchen B. Shoulder dystocia and associated risk factors with macrosomic infants born in California. Am J Obstet Gynecol 1998; 179:476.
  4. Geary M, McParland P, Johnson H, Stronge J. Shoulder dystocia--is it predictable? Eur J Obstet Gynecol Reprod Biol 1995; 62:15.
  5. Ouzounian JG, Gherman RB. Shoulder dystocia: are historic risk factors reliable predictors? Am J Obstet Gynecol 2005; 192:1933.
  6. Chang KW, Ankumah NA, Wilson TJ, et al. Persistence of Neonatal Brachial Plexus Palsy Associated with Maternally Reported Route of Delivery: Review of 387 Cases. Am J Perinatol 2016; 33:765.
  7. MacKenzie IZ, Shah M, Lean K, et al. Management of shoulder dystocia: trends in incidence and maternal and neonatal morbidity. Obstet Gynecol 2007; 110:1059.
  8. Dandolu V, Lawrence L, Gaughan JP, et al. Trends in the rate of shoulder dystocia over two decades. J Matern Fetal Neonatal Med 2005; 18:305.
  9. Dildy GA, Clark SL. Shoulder dystocia: risk identification. Clin Obstet Gynecol 2000; 43:265.
  10. Vidarsdottir H, Geirsson RT, Hardardottir H, et al. Obstetric and neonatal risks among extremely macrosomic babies and their mothers. Am J Obstet Gynecol 2011; 204:423.e1.
  11. Acker DB, Sachs BP, Friedman EA. Risk factors for shoulder dystocia. Obstet Gynecol 1985; 66:762.
  12. Sandmire HF, O'Halloin TJ. Shoulder dystocia: its incidence and associated risk factors. Int J Gynaecol Obstet 1988; 26:65.
  13. Boulet SL, Alexander GR, Salihu HM, Pass M. Macrosomic births in the united states: determinants, outcomes, and proposed grades of risk. Am J Obstet Gynecol 2003; 188:1372.
  14. Zhang X, Decker A, Platt RW, Kramer MS. How big is too big? The perinatal consequences of fetal macrosomia. Am J Obstet Gynecol 2008; 198:517.e1.
  15. Øverland EA, Vatten LJ, Eskild A. Pregnancy week at delivery and the risk of shoulder dystocia: a population study of 2,014,956 deliveries. BJOG 2014; 121:34.
  16. Langer O, Berkus MD, Huff RW, Samueloff A. Shoulder dystocia: should the fetus weighing greater than or equal to 4000 grams be delivered by cesarean section? Am J Obstet Gynecol 1991; 165:831.
  17. Modanlou HD, Komatsu G, Dorchester W, et al. Large-for-gestational-age neonates: anthropometric reasons for shoulder dystocia. Obstet Gynecol 1982; 60:417.
  18. McFarland MB, Trylovich CG, Langer O. Anthropometric differences in macrosomic infants of diabetic and nondiabetic mothers. J Matern Fetal Med 1998; 7:292.
  19. Coustan DR, Lowe LP, Metzger BE, et al. The Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study: paving the way for new diagnostic criteria for gestational diabetes mellitus. Am J Obstet Gynecol 2010; 202:654.e1.
  20. Overland EA, Spydslaug A, Nielsen CS, Eskild A. Risk of shoulder dystocia in second delivery: does a history of shoulder dystocia matter? Am J Obstet Gynecol 2009; 200:506.e1.
  21. Gherman RB, Chauhan S, Ouzounian JG, et al. Shoulder dystocia: the unpreventable obstetric emergency with empiric management guidelines. Am J Obstet Gynecol 2006; 195:657.
  22. Lewis DF, Raymond RC, Perkins MB, et al. Recurrence rate of shoulder dystocia. Am J Obstet Gynecol 1995; 172:1369.
  23. Ginsberg NA, Moisidis C. How to predict recurrent shoulder dystocia. Am J Obstet Gynecol 2001; 184:1427.
  24. Baskett TF, Allen AC. Perinatal implications of shoulder dystocia. Obstet Gynecol 1995; 86:14.
  25. Moore HM, Reed SD, Batra M, Schiff MA. Risk factors for recurrent shoulder dystocia, Washington state, 1987-2004. Am J Obstet Gynecol 2008; 198:e16.
  26. Usta IM, Hayek S, Yahya F, et al. Shoulder dystocia: what is the risk of recurrence? Acta Obstet Gynecol Scand 2008; 87:992.
  27. Kleitman V, Feldman R, Walfisch A, et al. Recurrent shoulder dystocia: is it predictable? Arch Gynecol Obstet 2016; 294:1161.
  28. Bingham J, Chauhan SP, Hayes E, et al. Recurrent shoulder dystocia: a review. Obstet Gynecol Surv 2010; 65:183.
  29. Mahony R, Walsh C, Foley ME, et al. Outcome of second delivery after prior macrosomic infant in women with normal glucose tolerance. Obstet Gynecol 2006; 107:857.
  30. Smith RB, Lane C, Pearson JF. Shoulder dystocia: what happens at the next delivery? Br J Obstet Gynaecol 1994; 101:713.
  31. Campbell MK, Ostbye T, Irgens LM. Post-term birth: risk factors and outcomes in a 10-year cohort of Norwegian births. Obstet Gynecol 1997; 89:543.
  32. Hassan AA. Shoulder dystocia: risk factors and prevention. Aust N Z J Obstet Gynaecol 1988; 28:107.
  33. Gemer O, Bergman M, Segal S. Labor abnormalities as a risk factor for shoulder dystocia. Acta Obstet Gynecol Scand 1999; 78:735.
  34. Sama JC, Iffy L. Maternal weight and fetal injury at birth: data deriving from medico-legal research. Med Law 1998; 17:61.
  35. Hope P, Breslin S, Lamont L, et al. Fatal shoulder dystocia: a review of 56 cases reported to the Confidential Enquiry into Stillbirths and Deaths in Infancy. Br J Obstet Gynaecol 1998; 105:1256.
  36. Perlow JH, Morgan MA, Montgomery D, et al. Perinatal outcome in pregnancy complicated by massive obesity. Am J Obstet Gynecol 1992; 167:958.
  37. Robinson H, Tkatch S, Mayes DC, et al. Is maternal obesity a predictor of shoulder dystocia? Obstet Gynecol 2003; 101:24.
  38. Kim SY, Sharma AJ, Sappenfield W, et al. Association of maternal body mass index, excessive weight gain, and gestational diabetes mellitus with large-for-gestational-age births. Obstet Gynecol 2014; 123:737.
  39. Cheng YW, Norwitz ER, Caughey AB. The relationship of fetal position and ethnicity with shoulder dystocia and birth injury. Am J Obstet Gynecol 2006; 195:856.
  40. Seigworth GR. Shoulder dystocia. Review of 5 years' experience. Obstet Gynecol 1966; 28:764.
  41. Kitzmiller JL, Mall JC, Gin GD, et al. Measurement of fetal shoulder width with computed tomography in diabetic women. Obstet Gynecol 1987; 70:941.
  42. Verspyck E, Goffinet F, Hellot MF, et al. Newborn shoulder width: a prospective study of 2222 consecutive measurements. Br J Obstet Gynaecol 1999; 106:589.
  43. Cohen BF, Penning S, Ansley D, et al. The incidence and severity of shoulder dystocia correlates with a sonographic measurement of asymmetry in patients with diabetes. Am J Perinatol 1999; 16:197.
  44. Klaij FA, Geirsson RT, Nielsen H, et al. Humerospinous distance measurements: accuracy and usefulness for predicting shoulder dystocia in delivery at term. Ultrasound Obstet Gynecol 1998; 12:115.
  45. Endres L, DeFranco E, Conyac T, et al. Association of Fetal Abdominal-Head Circumference Size Difference With Shoulder Dystocia: A Multicenter Study. AJP Rep 2015; 5:e099.
  46. Acker DB, Gregory KD, Sachs BP, Friedman EA. Risk factors for Erb-Duchenne palsy. Obstet Gynecol 1988; 71:389.
  47. Poggi SH, Stallings SP, Ghidini A, et al. Intrapartum risk factors for permanent brachial plexus injury. Am J Obstet Gynecol 2003; 189:725.
  48. Mehta SH, Bujold E, Blackwell SC, et al. Is abnormal labor associated with shoulder dystocia in nulliparous women? Am J Obstet Gynecol 2004; 190:1604.
  49. Acker DB, Sachs BP, Friedman EA. Risk factors for shoulder dystocia in the average-weight infant. Obstet Gynecol 1986; 67:614.
  50. McFarland M, Hod M, Piper JM, et al. Are labor abnormalities more common in shoulder dystocia? Am J Obstet Gynecol 1995; 173:1211.
  51. Lurie S, Levy R, Ben-Arie A, Hagay Z. Shoulder dystocia: could it be deduced from the labor partogram? Am J Perinatol 1995; 12:61.
  52. Laughon SK, Berghella V, Reddy UM, et al. Neonatal and maternal outcomes with prolonged second stage of labor. Obstet Gynecol 2014; 124:57.
  53. Benedetti TJ, Gabbe SG. Shoulder dystocia. A complication of fetal macrosomia and prolonged second stage of labor with midpelvic delivery. Obstet Gynecol 1978; 52:526.
  54. Dall'Asta A, Ghi T, Pedrazzi G, Frusca T. Does vacuum delivery carry a higher risk of shoulder dystocia? Review and meta-analysis of the literature. Eur J Obstet Gynecol Reprod Biol 2016; 204:62.
  55. Bofill JA, Rust OA, Schorr SJ, et al. A randomized prospective trial of the obstetric forceps versus the M-cup vacuum extractor. Am J Obstet Gynecol 1996; 175:1325.
  56. Caughey AB, Sandberg PL, Zlatnik MG, et al. Forceps compared with vacuum: rates of neonatal and maternal morbidity. Obstet Gynecol 2005; 106:908.
  57. Palatnik A, Grobman WA, Hellendag MG, et al. Predictors of shoulder dystocia at the time of operative vaginal delivery. Am J Obstet Gynecol 2016; 215:624.e1.
  58. Demissie K, Rhoads GG, Smulian JC, et al. Operative vaginal delivery and neonatal and infant adverse outcomes: population based retrospective analysis. BMJ 2004; 329:24.
  59. Thangaratinam S, Rogozinska E, Jolly K, et al. Effects of interventions in pregnancy on maternal weight and obstetric outcomes: meta-analysis of randomised evidence. BMJ 2012; 344:e2088.
  60. Hartling L, Dryden DM, Guthrie A, et al. Benefits and harms of treating gestational diabetes mellitus: a systematic review and meta-analysis for the U.S. Preventive Services Task Force and the National Institutes of Health Office of Medical Applications of Research. Ann Intern Med 2013; 159:123.
  61. Langer O, Conway DL. Level of glycemia and perinatal outcome in pregestational diabetes. J Matern Fetal Med 2000; 9:35.
  62. Langer O, Rodriguez DA, Xenakis EM, et al. Intensified versus conventional management of gestational diabetes. Am J Obstet Gynecol 1994; 170:1036.
  63. American College of Obstetricians and Gynecologists. Executive summary: neonatal brachial plexus palsy. Obstet Gynecol 2014; 123:902.
  64. American College of Obstetricians and Gynecologists’ Committee on Practice Bulletins—Obstetrics. Practice Bulletin No. 173: Fetal Macrosomia. Obstet Gynecol 2016; 128:e195.
  65. Rouse DJ, Owen J, Goldenberg RL, Cliver SP. The effectiveness and costs of elective cesarean delivery for fetal macrosomia diagnosed by ultrasound. JAMA 1996; 276:1480.
  66. Gonen R, Bader D, Ajami M. Effects of a policy of elective cesarean delivery in cases of suspected fetal macrosomia on the incidence of brachial plexus injury and the rate of cesarean delivery. Am J Obstet Gynecol 2000; 183:1296.
  67. Sacks DA, Chen W. Estimating fetal weight in the management of macrosomia. Obstet Gynecol Surv 2000; 55:229.
  68. Rouse DJ, Owen J. Prophylactic cesarean delivery for fetal macrosomia diagnosed by means of ultrasonography--A Faustian bargain? Am J Obstet Gynecol 1999; 181:332.
  69. Weeks JW, Pitman T, Spinnato JA 2nd. Fetal macrosomia: does antenatal prediction affect delivery route and birth outcome? Am J Obstet Gynecol 1995; 173:1215.
  70. Weiner Z, Ben-Shlomo I, Beck-Fruchter R, et al. Clinical and ultrasonographic weight estimation in large for gestational age fetus. Eur J Obstet Gynecol Reprod Biol 2002; 105:20.
  71. Ecker JL, Greenberg JA, Norwitz ER, et al. Birth weight as a predictor of brachial plexus injury. Obstet Gynecol 1997; 89:643.
  72. Alsunnari S, Berger H, Sermer M, et al. Obstetric outcome of extreme macrosomia. J Obstet Gynaecol Can 2005; 27:323.
  73. Hehir MP, Mchugh AF, Maguire PJ, Mahony R. Extreme macrosomia--obstetric outcomes and complications in birthweights >5000 g. Aust N Z J Obstet Gynaecol 2015; 55:42.
  74. Gherman RB, Ouzounian JG, Satin AJ, et al. A comparison of shoulder dystocia-associated transient and permanent brachial plexus palsies. Obstet Gynecol 2003; 102:544.
  75. Pondaag W, Allen RH, Malessy MJ. Correlating birthweight with neurological severity of obstetric brachial plexus lesions. BJOG 2011; 118:1098.
  76. American College of Obstetricians and Gynecologists. ACOG committee opinion no. 561: Nonmedically indicated early-term deliveries. Obstet Gynecol 2013; 121:911. Reaffirmed 2017.
  77. Boulvain M, Irion O, Dowswell T, Thornton JG. Induction of labour at or near term for suspected fetal macrosomia. Cochrane Database Syst Rev 2016; :CD000938.
  78. Kjos SL, Henry OA, Montoro M, et al. Insulin-requiring diabetes in pregnancy: a randomized trial of active induction of labor and expectant management. Am J Obstet Gynecol 1993; 169:611.
  79. Witkop CT, Neale D, Wilson LM, et al. Active compared with expectant delivery management in women with gestational diabetes: a systematic review. Obstet Gynecol 2009; 113:206.
  80. Gülmezoglu AM, Crowther CA, Middleton P, Heatley E. Induction of labour for improving birth outcomes for women at or beyond term. Cochrane Database Syst Rev 2012; :CD004945.