Efficacy and safety assessment of pliant forceps in assisted vaginal delivery

Forceps delivery often leads to increased maternal and neonatal complications, primarily attributed to the rigidity of traditional steel forceps, a major contributor to birth injury.

This study aims to develop obstetric forceps with reduced rigidity and assess the safety and effectiveness of the newly designed pliant forceps.

Pliant forceps with varying materials and shapes were produced by three-dimensional printing, and a pilot simulation determined the optimal design. Three fetal mannequins were developed to measure force changes exerted on the fetal head. Simulated births with several resistance intensities, were conducted to compare the real-time force between pliant forceps and Simpson forceps. Perineal distension was assessed by recording maximum perineal distention during a simulated forceps delivery using pliant forceps and Simpson forceps.

The pliant forceps, constructed from polylactic acid with solid blades and angled shanks, featured foam tape on the fetal sides. In simulation studies on term fetal head model, pliant forceps achieved successful assisted vaginal delivery across all resistance levels. Compared to Simpson forceps, pliant forceps consistently exerted lower force on the fetal head during assisted vaginal delivery. The maximum force applied by pliant forceps occurred at RA1 site on fetal head (67.11 ± 4.35 N, Simpson forceps: 99.12 ± 10.53 N, p < 0.001), and Simpson forceps reached its peak at RP2 site (177.37 ± 19.28 N, pliant forceps: 12.87 ± 5.11 N, p < 0.001). Similar results were obtained in simulation experiments on large and small fetal head models. Perineal distension was determined to be smaller in births with pliant forceps compared with that in births with Simpson forceps (lateral perineal distension: 76.6 mm vs. 92.6 mm, p < 0.001).

The three-dimensional-printed pliant forceps demonstrated reduced force on the fetal head and less perineal distension compared to Simpson forceps in simulated births, which holds potential for decreasing birth injuries and maternal birth canal injuries during forceps delivery. Further research is required to ensure the safety and efficacy of pliant forceps before clinical application.