Use of ultrasound parameters to predict shoulder dystocia in the diabetic pregnancy

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OBJECTIVE: While many ultrasound (U/S) parameters are used to predict macrosomia, a paucity of data exists regarding U/S prediction of the fetus at risk for shoulder dystocia (SHD). Potential markers of macrosomia (e.g. abdominal circumference (AC), cheek-to-cheek measurement, humeral soft tissue thickness) do not characterize the head-body size disparity presumed to be the mechanism for shoulder impaction. Sonographic estimation of the abdominal diameter (AD)/biparietal diameter (BPD) difference may better represent this disparity. We sought to investigate this measurement as a predictor of SHD in our diabetic population. METHODS: In an ongoing case-control study, diabetic women with delivciT complicated by SHD between January 1991 and July 1996 comprised the study group. They were stratified into birth weight (BW) categories in 50 gm intervals. Controls were selected from diabetic women with normal vaginal deliveries in a 2:1 ratio, matched for BW category. Patients were excluded if no U/S exam was obtained within 21 days of deliverv. We evaluated various thresholds of the AD - BPD difference It) best deli ne high- and low-risk groups, based on sensitivity, specificity, positive and negative predictive values (PPV and NPV). We then compared AD - BPD to AC >90th percentile and estimated fetal weight >4000 gm as predictors of SHD. RESULTS: 1-4 patients have met criteria for inclusion in the SHD group, matched to 28 control patients. Groups were similar in terms of maternal .ige, parity, gestational age, U/S to deliver)' interval, U/S estimated fetal weight, rate of pitocin use. and rale of operative vaginal delivery. AD - BPD (cm): ≥2.2 ≥2.6 ≥3M AC> 90% EFW > 4000 gm Sens (%) 50 13 7 79 36 Spec. (%) 67 92 96 33 83 PPV (%) 47 75 50 41 56 NPV (% )70 73 64 73 69 CONCLUSION; Our stuch suggests that the AD - BPD difference obtained sonographically may sufficiently detect anthropometric disproportion, which is the presumed antecedent for shoulder dystocia. However, the sensitivity of the test is low, and its clinical usefulness remains to be determined.

Original languageEnglish (US)
Pages (from-to)S79
JournalActa Diabetologica Latina
Issue number1 PART II
StatePublished - Dec 1 1997

ASJC Scopus subject areas

  • Internal Medicine
  • Endocrinology, Diabetes and Metabolism
  • Endocrinology


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