title: Computational modeling approach to study the effects of fetal head flexion during vaginal delivery.
abstract: OBJECTIVE
  The purpose of this study was to investigate the influence of fetal head flexion during vaginal delivery with a 3-dimensional computational finite element model.
  
  
  METHODS
  A finite element model of the pelvic skeletal structure, pelvic floor, and fetus was developed. The movements of the fetus during birth were simulated in engagement, descent, flexion, internal rotation, and extension of the fetal head. The opposite forces against the fetal descendent and the stress of the pelvic floor muscles were obtained on simulations with different degrees of head flexion.
  
  
  RESULTS
  The simulated increase in fetal head flexion is associated with lower values of opposite forces against the fetal descent. The descending fetus with abnormal head flexion also meets resistance in later stations. Lower stress on the pelvic floor was demonstrated with simulated increase in fetal head flexion during vaginal delivery.
  
  
  CONCLUSIONS
  This analytic evidence suggests that the fetal head flexion during vaginal delivery may facilitate birth and protect the pelvic floor.
authors.affiliation: Institute of Mechanical Engineering, Faculty of Engineering, University of Porto, Oporto, Portugal. mparente@fe.up.pt
authors.forename: Marco P
authors.initials: MP
authors.lastname: Parente
authors.forename: Renato M
authors.initials: RM
authors.lastname: Natal Jorge
authors.forename: Teresa
authors.initials: T
authors.lastname: Mascarenhas
authors.forename: António A
authors.initials: AA
authors.lastname: Fernandes
authors.forename: Agnaldo L
authors.initials: AL
authors.lastname: Silva-Filho
mesh_terms: D003198:Computer Simulation; D036861:Delivery, Obstetric; D005260:Female; D005333:Fetus / Q000502:physiology*; D020342:Finite Element Analysis; D019416:Head Movements / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D036801:Parturition / Q000502:physiology; D017773:Pelvic Floor / Q000502:physiology; D011247:Pregnancy