The magnitude and distribution of pressure of obstetric forceps on a fetal head mannequin model

Introduction

Considerations for forceps specific shape and dimensions are usually not available for review. This study evaluates surfaces of contact, magnitude of force, and pressure distribution of different forceps on a fetal head model.

Materials and Methods

Pressure-sensitive films were cut following planar impressions of commonly used forceps. After biparieto-bimalar applications on a term fetal head model, the films were scanned and areas of contact, pressure, and force calculated. Comparisons were made between different types of film and forceps. Significance was considered if p < 0.05.

Results

Fifty-four forceps impressions were analyzed. With decreasing film sensitivities, smaller contact areas (p < 0.01) and higher mean pressures (p < 0.01) were detected. No significant differences were noted between different forceps regarding contact areas, pressure, or force. Most impressions reveal pressure points in the range of 980–1400 psi.

Conclusion

Ergonomic improvements can be made to the design of forceps blades in order to improve maternal-fetal morbidity.