Comparing forces on the fetal neck in breech delivery in lithotomy versus all-fours position: a simulation model.

PURPOSE: To measure forces applied to the fetal neck, in a simulation model for breech delivery, in both lithotomy versus all-fours position. METHODS: We used a Laerdal SimMom simulator and a Birthing Baby together with PROMPT Flex Software. The descent of the fetus was accomplished using the Automatic Delivery Module 2. The baby was always in breech position; the SimMom in either all-fours or lithotomy positions. Sensors were located inside the fetal neck region to simulate forces applied to the plexus. RESULTS: The lowest force on the fetal neck region was recorded for the delivery in all-fours position without further maneuvers (mean force 58.70 Newton, standard deviation 2.54 N). As weight was added to the baby, the force increased (i.e. + 500 g, mean force 71.8 N, SD 3.08 N, p < 0.001). Delivery in lithotomy position resulted in a mean force of 81.56 N (SD 19.55 N). The force significantly increased in case of delivery of the head without assistance from contractions (mean force 127.93 N, SD 23.10 N). In all-fours position, the delivery of the fetal head from pelvic floor level without contractions (Frank's Nudge maneuver) resulted in a mean force of 118.45 N (SD 15.48 N, p = 0.02). Maneuvers for shoulder dystocia (the inverted type that can occur during breech delivery) led to significantly higher mean forces independent from birthing positions. CONCLUSION: Breech delivery in all-fours position was associated with the lowest force acting on the fetal neck in our simulation model.

Vacuum delivery in all-fours position: is it a valuable, brand-new option?

Since all-fours birth position is considered to decrease the rate of failure of vaginal birth and the risk of negative maternal and fetal outcomes, we wondered if all-fours would be favorable in case of operative vaginal delivery with obstetrical vacuum. We performed a simulation of vacuum application on a mannequin settled in all-fours position and we filmed this new application for diffusion among clinicians. We suggest that the all-fours position be considered and investigated in further studies as a possible way of delivery in case of operative vaginal delivery.