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A numerical study on fetal head molding during labor


Moura, Rita; Borges, Margarida; Vila Pouca, Maria C P; Oliveira, Dulce A; Parente, Marco P L; Kimmich, Nina; Mascarenhas, Teresa; Natal, Renato M (2021). A numerical study on fetal head molding during labor. International Journal for Numerical Methods in Biomedical Engineering, 37(1):e3411.

Abstract

During vaginal delivery, the fetal head molds into an elongated shape to adapt to the birth canal, a process known as fetal head molding. However, excessive molding can occur due to prolonged labor or strong contractions, leading to several disorders on the fetal head. This work aims to perform a numerical study on the biomechanics of fetal head molding by measuring specific diameters and the corresponding molding index. A finite element model of the pelvic floor muscles and the fetal body was used. The fetal head is composed of the skin and soft tissues, the skull with sutures and fontanelles, and the brain. The sutures and fontanelles were modeled with membrane elements and characterized by a visco‐hyperelastic constitutive model adapted to a plane stress state. Simulations were performed to replicate the second stage of labor in the vertex presentation and occipito‐anterior position. With the introduction of viscoelasticity to assess a time‐dependent response, a prolonged second stage of labor resulted in higher molding. The pressure exerted by the birth canal and surrounding structures, along with the presence of the pelvic floor muscles, led to a percentage of molding of 9.1%. Regarding the pelvic floor muscles, a 19.4% reduction on the reaction forces and a decrease of 2.58% in muscle stretching was reported, which indicates that sufficient molding may lead to fewer injuries. The present study demonstrates the importance of focusing on the fetus injuries with non‐invasive methods that can allow to anticipate complications during labor.

Abstract

During vaginal delivery, the fetal head molds into an elongated shape to adapt to the birth canal, a process known as fetal head molding. However, excessive molding can occur due to prolonged labor or strong contractions, leading to several disorders on the fetal head. This work aims to perform a numerical study on the biomechanics of fetal head molding by measuring specific diameters and the corresponding molding index. A finite element model of the pelvic floor muscles and the fetal body was used. The fetal head is composed of the skin and soft tissues, the skull with sutures and fontanelles, and the brain. The sutures and fontanelles were modeled with membrane elements and characterized by a visco‐hyperelastic constitutive model adapted to a plane stress state. Simulations were performed to replicate the second stage of labor in the vertex presentation and occipito‐anterior position. With the introduction of viscoelasticity to assess a time‐dependent response, a prolonged second stage of labor resulted in higher molding. The pressure exerted by the birth canal and surrounding structures, along with the presence of the pelvic floor muscles, led to a percentage of molding of 9.1%. Regarding the pelvic floor muscles, a 19.4% reduction on the reaction forces and a decrease of 2.58% in muscle stretching was reported, which indicates that sufficient molding may lead to fewer injuries. The present study demonstrates the importance of focusing on the fetus injuries with non‐invasive methods that can allow to anticipate complications during labor.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Clinic for Obstetrics
Dewey Decimal Classification:610 Medicine & health
Scopus Subject Areas:Physical Sciences > Software
Physical Sciences > Biomedical Engineering
Physical Sciences > Modeling and Simulation
Life Sciences > Molecular Biology
Physical Sciences > Computational Theory and Mathematics
Physical Sciences > Applied Mathematics
Uncontrolled Keywords:Modelling and Simulation, Computational Theory and Mathematics, Software, Applied Mathematics, Molecular Biology, Biomedical Engineering
Language:English
Date:1 January 2021
Deposited On:04 Feb 2021 13:42
Last Modified:05 Feb 2021 21:05
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:2040-7939
OA Status:Closed
Publisher DOI:https://doi.org/10.1002/cnm.3411
PubMed ID:33131201

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