Shoulder dystocia and associated risk factors with macrosomic infants born in California


      OBJECTIVE: The purpose of this study was to examine the 1-year incidence statewide in California of shoulder dystocia and its associated risk factors.
      STUDY DESIGN: With a data set that contains computer-linked records from the birth certificate and hospital discharge records of both mother and baby, all births of infants >3500 g in >300 civilian acute care hospitals in California in 1992 were analyzed. All cases of shoulder dystocia were identified from discharge records, birth certificates, or both and were analyzed with both bivariate and multivariate techniques to identify specific risk factors.
      RESULTS: A total of 175,886 vaginal births of infants >3500 g were included in our database, of which 6238 infants (3%) had shoulder dystocia. The percentages of births complicated by shoulder dystocia for unassisted births not complicated by diabetes were 5.2% for infants 4000 to 4250 g, 9.1% for those 4250 to 4500 g, 14.3% for 4500 to 4750, and 21.1% for those 4750 to 5000 g. Shoulder dystocia increased by approximately 35% to 45% in vacuum- or forceps-assisted births to nondiabetic mothers. Similar increases were seen in unassisted births to diabetic mothers. The risk of shoulder dystocia for assisted births to diabetic mothers was even more dramatic: 12.2% for infants 4000 to 4250 g, 16.7% for those 4250 to 4500 g, 27.3% for those 4500 to 4750 g, and 34.8% for those 4750 to 5000 g. After controlling for other parameters, there was an increased risk of shoulder dystocia associated with diabetes (odds ratio 1.7), assisted delivery (odds ratio 1.9), and induction of labor (odds ratio 1.3). Rates of birth trauma, asphyxia, and length of stay were all increased among births complicated by shoulder dystocia.
      CONCLUSION: This information on the incidence of shoulder dystocia and associated risk factors for a large statewide population may assist providers of obstetric care in counseling patients when macrosomia is suspected. The inaccuracy of estimating fetal weight is a severe limitation in attempting to establish guidelines designed to prevent shoulder dystocia. (Am J Obstet Gynecol 1998;179:476-80.)


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        • Benedetti TJ
        • Gabbe SG
        Shoulder dystocia: a complication of fetal macrosomia and prolonged second state of labor and midpelvic delivery.
        Obstet Gynecol. 1978; 52: 526-530
        • Spellacy WN
        • Miller S
        • Winegar A
        • Peterson PQ
        Macrosomia: maternal characteristics and infant complications.
        Obstet Gynecol. 1985; 66: 158-161
        • Lipscomb KR
        • Gregory K
        • Shaw K
        The outcome of macrosomic infants weighing at least 4500 grams: Los Angeles County + University of Southern California experience.
        Obstet Gynecol. 1995; 85: 558-564
        • 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: 831-837
        • Benacerraf BR
        • Gilman R
        • Frigoletto FD
        Sonographically estimated fetal weights: accuracy and limitation.
        Am J Obstet Gynecol. 1988; 159: 1118-1121
        • Field NT
        • Piper JM
        • Langer O
        The effect of maternal obesity on the accuracy of fetal weight estimation.
        Obstet Gynecol. 1995; 86: 102-107
        • Hedriana HL
        • Moore TR
        A comparison of single versus multiple growth ultrasonographic examinations in predicting birth weight.
        Am J Obstet Gynecol. 1994; 170: 1600-1606
      1. American College of Obstetricians and Gynecologists. The College, Washington1995 (Technical Bulletin No.: 218)
        • Nocon JJ
        • McKenzie DK
        • Thomas LJ
        • Hansell RS
        Shoulder dystocia: an analysis of risks and obstetric maneuvers.
        Am J Obstet Gynecol. 1993; 6: 1732-1737
        • Baskett TF
        • Allen AC
        Perinatal implications of shoulder dystocia.
        Obstet Gynecol. 1995; 86: 14-17
        • Graham EM
        • Forouzan I
        • Morgan MA
        A retrospective analysis of Erb’s palsy cases and their relationship to birth weight and trauma.
        J Matern Fetal Med. 1997; 6: 1-5
        • Beasley JW
        • Damos JR
        • Roberts RG
        • Nesbitt TS
        The advanced life support in obstetrics (ALSO) course: a national program to enhance obstetrical emergency skills and to support maternity care practice.
        Arch Fam Med. 1994; 3: 1037-1041