Birth: Issues in Perinatal CarePredictors of Shoulder Dystocia: A Retrospective Case–Control Study

ℹ️ Observational Association Only Evidence

Investigators reviewed 56,957 vaginal births from a prospectively audited, single-center database and identified 58 shoulder dystocia cases matched with 880 controls. Fetal macrosomia showed the strongest independent association, while maternal overweight and diabetes were also associated with increased odds. The retrospective findings reinforce known risk factors but do not establish a prospectively validated prediction model.

Clinical Considerations

• Birthweight of at least 4,000 g was associated with substantially higher shoulder dystocia odds: adjusted OR, 22.99; 95% CI, 8.49–62.25.
• Maternal BMI of at least 25 kg/m² was associated with increased odds: adjusted OR, 3.44; 95% CI, 1.41–8.44.
• Maternal diabetes was associated with increased odds: adjusted OR, 2.32; 95% CI, 1.12–4.78.
• Nulliparity did not remain independently significant after adjustment, suggesting confounding by maternal age, fetal size, or related characteristics.
• Maternal or neonatal injury occurred in 8.6% of cases versus 0.7% of controls, although individual outcomes were combined because events were infrequent.
• Only 58 shoulder dystocia events occurred, with possible underdocumentation, wide confidence intervals, a high Cesarean rate, and no ultrasound-estimated fetal weight data.

Practice Applications

• Recognize macrosomia as an important risk signal without treating birthweight estimates as reliable standalone predictors.
• Integrate diabetes, maternal BMI, fetal growth, and delivery context into individualized intrapartum risk assessment.
• Avoid interpreting nulliparity as an independent predictor based on this analysis.
• Maintain delivery-team readiness because many shoulder dystocia events remain difficult to predict before birth.
• Interpret the findings as population-specific and hypothesis-generating pending external or prospective validation.