BACKGROUND: The exact positioning of the dominant hand at the time of manual perineal protection (MPP) is not clearly specified. The main aim of this work was to identify the place on the perineum where pressure needs to be applied to achieve optimal forward fetal head displacement away from the anal sphincters using the bregma to posterior fourchette distance (BFD) and the perineal body length (PBL). METHODS: This was a two-center prospective cohort study. Term cephalic singleton nulliparous women having spontaneous vaginal delivery were considered eligible for recruitment into the study. Once crowning was diagnosed and just prior the initiation of manual perineal protection (MPP) or cutting an episiotomy, the BFD and PBL were measured using a standardized measurement protocol. RESULTS AND DISCUSSION: A total of 100 women (50 women in each center) were recruited into the study. The overall mean BFD was 2.8 ± 0.5 cm. The overall mean PBL was 4.4 ± 0.8 cm. There were no statistically significant differences between the measurements taken in both units regarding BFD or PBL (p = 0.81 and 0.10 respectively). There was a weak correlation between both measurements. Based on our measured parameters, it seems that the most effective point to apply perineal pressure to displace the head away from the anus is approximately 1 - 1.5 cm anterior to the anal margin. CONCLUSION: Measurements generated by this study will form the bases of future biomechanical studies to confirm their validity.

• Klíčová slova
• Manual perineal protection, Perineal body, Perineal mapping, Perineal tension,
• MeSH
• anální kanál fyziologie   MeSH
• dospělí MeSH
• epiziotomie * statistika a číselné údaje   metody   MeSH
• hlava * MeSH
• lidé MeSH
• mladý dospělý MeSH
• perineum * MeSH
• prospektivní studie MeSH
• těhotenství MeSH
• tlak MeSH
• vedení porodu metody   MeSH
• Check Tag
• dospělí MeSH
• lidé MeSH
• mladý dospělý MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• multicentrická studie MeSH

INTRODUCTION AND HYPOTHESIS: Several studies have assessed birth-related deformations of the levator ani muscle (LAM) and perineum on models that depicted these elements in isolation. The main aim of this study was to develop a complex female pelvic floor computational model using the finite element method to evaluate points and timing of maximum stress at the LAM and perineum in relation to the birth process. METHODS: A three-dimensional computational model of the female pelvic floor was created and used to simulate vaginal birth based on data from previously described real-life MRI scans. We developed three models: model A (LAM without perineum); model B (perineum without LAM); model C (a combined model with both structures). RESULTS: The maximum stress in the LAM was achieved when the vertex was 9 cm below the ischial spines and measured 37.3 MPa in model A and 88.7 MPa in model C. The maximum stress in the perineum occurred at the time of distension by the suboocipito-frontal diameter and reached 86.7 MPa and 119.6 MPa in models B and C, respectively, while the stress in the posterior fourchette caused by the suboccipito-bregmatic diameter measured 36.9 MPa for model B and 39.8 MPa for model C. CONCLUSIONS: Including perineal structures in a computational birth model simulation affects the level of stress at the LAM. The maximum stress at the LAM and perineum seems to occur when the head is lower than previously anticipated.

• Klíčová slova
• Birth, Delivery, Levator, Modeling, Muscle, Partum, Perineal, Stress, Tension,
• MeSH
• analýza metodou konečných prvků MeSH
• lidé MeSH
• pánevní dno * diagnostické zobrazování   MeSH
• perineum MeSH
• těhotenství MeSH
• vedení porodu * MeSH
• zubní porcelán MeSH
• Check Tag
• lidé MeSH
• těhotenství MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• finesse MeSH Prohlížeč
• zubní porcelán MeSH