Antenatal risk score for prediction of shoulder dystocia with focus on fetal ultrasound data


      Shoulder dystocia is one of the most threatening complications during delivery, and although it is difficult to predict, individual risk should be considered when counseling for mode of delivery.


      This study aimed to develop and validate a risk score for shoulder dystocia based on fetal ultrasound and maternal data from 15,000 deliveries.

      Study Design

      Data were retrospectively obtained of deliveries in 3 tertiary centers between 2014 and 2017 for the derivation cohort and between 2018 and 2020 for the validation cohort. Inclusion criteria were singleton pregnancy, vaginal delivery in cephalic presentation at ≥37+0 weeks’ gestation, and fetal biometry data available within 2 weeks of delivery. Independent predictors were determined by multivariate regression analysis in the derivation cohort, and a score was developed on the basis of the effect of the predictors.


      The derivation cohort consisted of 7396 deliveries with a 0.91% rate of shoulder dystocia, and the validation cohort of 7965 deliveries with a 1.0% rate of shoulder dystocia. Among all women, 13.8% had diabetes mellitus, and 12.1% were obese (body mass index ≥30 kg/m2). Independent risk factors in the derivation cohort were: estimated fetal weight ≥4250 g (odds ratio, 4.27; P=.002), abdominal-head-circumference ≥2.5 cm (odds ratio, 3.96; P<.001), and diabetes mellitus (odds ratio, 2.18; P=.009). On the basis of the strength of effect, a risk score was developed: estimated fetal weight ≥4250 g=2, abdominal-head-circumference ≥2.5 cm=2, and diabetes mellitus=1. The risk score predicted shoulder dystocia with moderate discriminatory ability (area under the receiver-operating characteristic curve, 0.69; P<.001; area under the receiver-operating characteristic curve, 0.71; P<.001) and good calibration (Hosmer–Lemeshow goodness-of-fit; P=.466; P=.167) for the derivation and validation cohorts, respectively. With 1 score point, 16 shoulder dystocia cases occurred in 1764 deliveries, with 0.6% shoulder dystocia incidence and a number needed to treat with cesarean delivery to avoid 1 case of shoulder dystocia of 172 (2 points: 38/1809, 2.1%, 48; 3 points: 18/336, 5.4%, 19; 4 points: 10/96, 10.5%, 10; and 5 points: 5/20, 25%, 4); 40.8% of the shoulder dystocia cases occurred without risk factors.


      The presented risk score for shoulder dystocia may act as a supplemental tool for the clinical decision-making regarding mode of delivery. According to our score model, in pregnancies with a score ≤2, meaning having solely estimated fetal weight ≥4250 g, or abdominal-head-circumference ≥2.5, or diabetes mellitus, cesarean delivery for prevention of shoulder dystocia should not be recommended because of the high number needed to treat to avoid 1 case of shoulder dystocia. Conversely, in patients with a score of ≥4 with or without diabetes mellitus, cesarean delivery may be considered. However, in 40% of the shoulder dystocia cases, no risk factors had been present.

      Key words

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to American Journal of Obstetrics & Gynecology
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Ouzounian J.G.
        Shoulder dystocia: incidence and risk factors.
        Clin Obstet Gynecol. 2016; 59: 791-794
        • Øverland E.A.
        • Vatten L.J.
        • Eskild A.
        Pregnancy week at delivery and the risk of shoulder dystocia: a population study of 2,014,956 deliveries.
        BJOG. 2014; 121: 34-41
      1. Practice Bulletin No. 178 Summary: shoulder dystocia.
        Obstet Gynecol. 2017; 129: 961-962
        • Gherman R.B.
        • Goodwin T.M.
        • Souter I.
        • Neumann K.
        • Ouzounian J.G.
        • Paul R.H.
        The McRoberts’ maneuver for the alleviation of shoulder dystocia: how successful is it?.
        Am J Obstet Gynecol. 1997; 176: 656-661
        • Tsur A.
        • Sergienko R.
        • Wiznitzer A.
        • Zlotnik A.
        • Sheiner E.
        Critical analysis of risk factors for shoulder dystocia.
        Arch Gynecol Obstet. 2012; 285: 1225-1229
        • Gherman R.B.
        • Ouzounian J.G.
        • Satin A.J.
        • Goodwin T.M.
        • Phelan J.P.
        A comparison of shoulder dystocia-associated transient and permanent brachial plexus palsies.
        Obstet Gynecol. 2003; 102: 544-548
        • Michelotti F.
        • Flatley C.
        • Kumar S.
        Impact of shoulder dystocia, stratified by type of manoeuvre, on severe neonatal outcome and maternal morbidity.
        Aust N Z J Obstet Gynaecol. 2018; 58: 298-305
        • Gherman R.B.
        Shoulder dystocia: prevention and management.
        Obstet Gynecol Clin North Am. 2005; 32: 297-305
        • Gherman R.B.
        • Chauhan S.
        • Ouzounian J.G.
        • Lerner H.
        • Gonik B.
        • Goodwin T.M.
        Shoulder dystocia: the unpreventable obstetric emergency with empiric management guidelines.
        Am J Obstet Gynecol. 2006; 195: 657-672
        • Santos P.
        • Hefele J.G.
        • Ritter G.
        • Darden J.
        • Firneno C.
        • Hendrich A.
        Population-based risk factors for shoulder dystocia.
        J Obstet Gynecol Neonatal Nurs. 2018; 47: 32-42
        • Zhang C.
        • Wu Y.
        • Li S.
        • Zhang D.
        Maternal prepregnancy obesity and the risk of shoulder dystocia: a meta-analysis.
        BJOG. 2018; 125: 407-413
        • Dodd J.M.
        • Catcheside B.
        • Scheil W.
        Can shoulder dystocia be reliably predicted?.
        Aust N Z J Obstet Gynaecol. 2012; 52: 248-252
        • Gherman R.B.
        Shoulder dystocia: an evidence-based evaluation of the obstetric nightmare.
        Clin Obstet Gynecol. 2002; 45: 345-362
        • Bardenheier B.H.
        • Imperatore G.
        • Devlin H.M.
        • Kim S.Y.
        • Cho P.
        • Geiss L.S.
        Trends in pre-pregnancy diabetes among deliveries in 19 U.S. states, 2000–2010.
        Am J Prev Med. 2015; 48: 154-161
        • Bardenheier B.H.
        • Imperatore G.
        • Gilboa S.M.
        • et al.
        Trends in gestational diabetes Among hospital deliveries in 19 U.S. States, 2000–2010.
        Am J Prev Med. 2015; 49: 12-19
        • Devlieger R.
        • Benhalima K.
        • Damm P.
        • et al.
        Maternal obesity in Europe: where do we stand and how to move forward?: a scientific paper commissioned by the European Board and College of Obstetrics and Gynaecology (EBCOG).
        Eur J Obstet Gynecol Reprod Biol. 2016; 201: 203-208
        • Practice Bulletin
        No 178: shoulder dystocia.
        Obstet Gynecol. 2017; 129: e123-e133
        • Ouzounian J.G.
        • Korst L.M.
        • Miller D.A.
        • Lee R.H.
        Brachial plexus palsy and shoulder dystocia: obstetric risk factors remain elusive.
        Am J Perinatol. 2013; 30: 303-307
        • Deutsche Diabetes Gesellschaft
        Diabetes in der Schwangerschaft: Arbeitsgemeinschaft der. Wiss Med Fachgesellschaften (AWMF). 5th ed.
        (Available at:)
      2. Rasmussen KM, Yaktine AL, Institute of Medicine (US) and National Research Council (US) Committee to Reexamine IOM Pregnancy Weight Guidelines, eds. Weight gain during pregnancy: reexamining the guidelines. The National Academies Collection: reports funded by. Washington (DC): National Institutes of Health 2009.

        • Deutsche Gesellschaft für Gynäkologie und Geburtshilfe (DGGG)
        Deutsche Gesellschaft für Hebammenwissenschaft (DGfH). Vaginale Geburt Terminol Arbeitsgem Wiss Med Fachgesellschaften (AWMF) 2020.
        (Available at:)
        • Hadlock F.P.
        • Harrist R.B.
        • Sharman R.S.
        • Deter R.L.
        • Park S.K.
        Estimation of fetal weight with the use of head, body, and femur measurements—a prospective study.
        Am J Obstet Gynecol. 1985; 151: 333-337
        • Vetterlein J.
        • Doehmen C.A.E.
        • Voss H.
        • et al.
        Antenatal risk prediction of shoulder dystocia: influence of diabetes and obesity: a multicenter study.
        Arch Gynecol Obstet. 2021; 304: 1169-1177
        • Hong W.
        • Lillemoe K.D.
        • Pan S.
        • et al.
        Development and validation of a risk prediction score for severe acute pancreatitis.
        J Transl Med. 2019; 17: 146
        • Chien T.L.
        • Hsiao F.Y.
        • Chen L.J.
        • Wen Y.W.
        • Lin S.W.
        Development and validation of a risk scoring system for cephamycin-associated hemorrhagic events.
        Sci Rep. 2019; 9: 12905
        • Thabane M.
        • Simunovic M.
        • Akhtar-Danesh N.
        • Marshall J.K.
        Development and validation of a risk score for post-infectious irritable bowel syndrome.
        Am J Gastroenterol. 2009; 104: 2267-2274
        • Voigt M.
        • Rochow N.
        • Schneider K.T.
        • et al.
        [New percentile values for the anthropometric dimensions of singleton neonates: analysis of perinatal survey data of 2007–2011 from all 16 states of Germany].
        Z Geburtshilfe Neonatol. 2014; 218: 210-217
        • Snijders R.J.
        • Nicolaides K.H.
        Fetal biometry at 14–40 weeks’ gestation.
        Ultrasound Obstet Gynecol. 1994; 4: 34-48
        • Ouzounian J.G.
        • Korst L.M.
        • Sanchez M.
        • et al.
        Clinical risk factors do not predict shoulder dystocia.
        J Reprod Med. 2016; 61: 575-580
        • Heinonen K.
        • Saisto T.
        • Gissler M.
        • Kaijomaa M.
        • Sarvilinna N.
        Rising trends in the incidence of shoulder dystocia and development of a novel shoulder dystocia risk score tool: a nationwide population-based study of 800 484 Finnish deliveries.
        Acta Obstet Gynecol Scand. 2021; 100: 538-547
        • Gupta M.
        • Hockley C.
        • Quigley M.A.
        • Yeh P.
        • Impey L.
        Antenatal and intrapartum prediction of shoulder dystocia.
        Eur J Obstet Gynecol Reprod Biol. 2010; 151: 134-139
        • Rouse D.J.
        • Owen J.
        Prophylactic cesarean delivery for fetal macrosomia diagnosed by means of ultrasonography—a Faustian bargain?.
        Am J Obstet Gynecol. 1999; 181: 332-338
        • Weiner Z.
        • Ben-Shlomo I.
        • Beck-Fruchter R.
        • Goldberg Y.
        • Shalev E.
        Clinical and ultrasonographic weight estimation in large for gestational age fetus.
        Eur J Obstet Gynecol Reprod Biol. 2002; 105: 20-24
        • Dittkrist L.
        • Vetterlein J.
        • Henrich W.
        • et al.
        Percent error of ultrasound examination to estimate fetal weight at term in different categories of birth weight with focus on maternal diabetes and obesity.
        BMC Pregnancy Childbirth. 2022; 22: 241
        • 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-e104
        • Palatnik A.
        • Grobman W.A.
        • Hellendag M.G.
        • Janetos T.M.
        • Gossett D.R.
        • Miller E.S.
        Predictors of shoulder dystocia at the time of operative vaginal delivery.
        Am J Obstet Gynecol. 2016; 215: 624.e1-624.e5
        • Ehrenberg H.M.
        • Mercer B.M.
        • Catalano P.M.
        The influence of obesity and diabetes on the prevalence of macrosomia.
        Am J Obstet Gynecol. 2004; 191: 964-968
        • Dyachenko A.
        • Ciampi A.
        • Fahey J.
        • Mighty H.
        • Oppenheimer L.
        • Hamilton E.F.
        Prediction of risk for shoulder dystocia with neonatal injury.
        Am J Obstet Gynecol. 2006; 195: 1544-1549
        • Tsur A.
        • Batsry L.
        • Toussia-Cohen S.
        • et al.
        Development and validation of a machine-learning model for prediction of shoulder dystocia.
        Ultrasound Obstet Gynecol. 2020; 56: 588-596
        • Sokol R.J.
        • Blackwell S.C.
        American College of Obstetricians and Gynecologists. Committee on Practice Bulletins-Gynecology. ACOG practice bulletin: shoulder dystocia. Number 40, November 2002. (Replaces practice pattern number 7, October 1997).
        Int J Gynaecol Obstet. 2003; 80: 87-92
        • Maresh M.J.
        • Holmes V.A.
        • Patterson C.C.
        • et al.
        Glycemic targets in the second and third trimester of pregnancy for women with type 1 diabetes.
        Diabetes Care. 2015; 38: 34-42
        • Secher A.L.
        • Bytoft B.
        • Tabor A.
        • Damm P.
        • Mathiesen E.R.
        Fetal sonographic characteristics associated with shoulder dystocia in pregnancies of women with type 1 diabetes.
        Acta Obstet Gynecol Scand. 2015; 94: 1105-1111
        • Robson M.
        Shoulder dystocia: is it time to think differently?.
        Aust N Z J Obstet Gynaecol. 2019; 59: 605-607