Comparing clinician-applied loads for routine, difficult, and shoulder dystocia deliveries

OBJECTIVE: Our goal was to examine and compare clinician-applied loads during simulated vaginal delivery. STUDY DESIGN: We developed a birthing model and a microcomputer data acquisition system and used them to measure clinician-applied extraction forces, moment, and rates for three perceived categories of delivery. In 39 experiments, clinicians simulated delivery of the fetal shoulders during vaginal delivery for routine, difficult, and shoulder dystocia deliveries. RESULTS: Clinicians averaged 84 N combined force and 473 N-cm neck-bending moment for routine deliveries, 122 N and 697 N-cm for difficult deliveries, and 163 N and 700 N-cm for shoulder dystocia deliveries (p < 0.002). No force or moment parameter was associated with clinician gender or experience. Force levels exceeding 100 N are reached for many clinicians (74% and 82%) for difficult and shoulder dystocia deliveries and for some clinicians (31%) for routine deliveries (p < 0.0001). CONCLUSION: We conclude that simulating shoulder dystocia in the laboratory may be useful in measuring extraction forces and neck-bending moment and that birthing models can be used to train clinicians in force, moment, and rate perception.