Levator Ani Muscle Stretch Induced by Simulated Vaginal Birth

Lien, Kuo Cheng; Mooney, Brian; DeLancey, John O.L.; Ashton‐Miller, James A.

doi:10.1097/01.aog.0000109207.22354.65

Cited by 402 publications

(316 citation statements)

References 21 publications

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“…This stretching could result in a tearing of the muscle body, detachment from its bony insertions, and neuropathic injury. [6] Pelvic magnetic resonance imaging (MRI) has emerged as a noninvasive means of evaluating muscle morphology, both normal and pathologic. Abnormal muscle can be identified by a change in the thickness or topography of the muscle.…”

Section: Introductionmentioning

confidence: 99%

Levator ani abnormality 6 weeks after delivery persists at 6 months

Branham

Thomas

Jaffe

et al. 2007

American Journal of Obstetrics and Gynecology

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Objective: Assess post partum changes in the levator ani muscle using magnetic resonance (MR) imaging and relate these changes to obstetrical events and risk factors associated with pelvic floor dysfunction.Study Design: A board certified radiologist specializing in abdominal imaging evaluated 146 pelvic MR studies from 57 primiparas 6 weeks and 6 months after first obstetrical delivery and 32 nulliparas. A yes/no determination of muscle body and insertion integrity, muscle thinning, and measurement of muscle thickness in mm was made for each of four muscle sites: right and left puborectalis, right and left ileococcygeous.Incidence of muscle abnormality and mean muscle thickness were tested in pairs between 1) nulliparas and 6 week primiparas, 2) 6 week and 6 month primipara pairs, and 3) three age/race groups using test of two proportions and one-way anova.Results: Initial review indicated only 3 subjects not of African-American (AA) or Caucasian (W) race, and only 1 AA primipara of age ≥30yrs, therefore statistical analysis was limited to 45 primiparas and 25 nulliparas. Incidence of any abnormality at any of the 4 sites was considered abnormal. Frequency of abnormal muscle by race and age is shown in the In those subjects recovering to normal MR by 6 months, an average of nearly 60% increase in R puborectalis muscle thickness compared to that seen at 6 weeks indicated the extent of the injury. Subjects with injury to both the puborectalis and ileococcygeous at 6 weeks did not recover to normal at 6 months, whereas those with injury only to the puborectalis tended to have normal MR at 6 months. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. NIH Public AccessAuthor Manuscript Conclusions: Nulliparity did not guarantee a normal assessment of levator ani anatomy by our blinded reader, and frequency of injury in this series is somewhat greater than that previously reported for primiparas. Younger Caucasian primiparas had a better recovery at 6 months than older Caucasians. Subjects experiencing more global injury, in particular to the ileococcygeous, tended not to recover muscle bulk.

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Section: Introductionmentioning

confidence: 99%

Levator ani abnormality 6 weeks after delivery persists at 6 months

Branham

Thomas

Jaffe

et al. 2007

American Journal of Obstetrics and Gynecology

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“…Thus, although these muscles are made up of tonic contraction fibers 21 , resistant to fatigue, it seems that their muscle fibers need to increase the tone to maintain their support and continence functions, and offset this progressive overload in PFMs.The results obtained in this study point to a significant increase in maternal body mass and BMI during pregnancy. Despite all the pregnant women in this study having normal pre-pregnancy BMI 9 , it may be noted that, during pregnancy, 15.8% were overweight and 15.8% were obese.…”

Section: Discussionmentioning

confidence: 99%

Existe alteração na função dos músculos do assoalho pélvico e abdominais de primigestas no segundo e terceiro trimestre gestacional?

2016

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RESUMO O objetivo deste estudo é comparar a função dos músculos do assoalho pélvico no segundo e terceiro trimestre gestacional de primigestas. Foi desenvolvido em duas unidades de Saúde da Família do município de Aracaju (SE). As gestantes foram submetidas a três avaliações da função dos músculos do assoalho pélvico por meio da eletromiografia de superfície: até 16 semanas gestacionais, entre a 24ª-28ª e 34ª-36ª semanas gestacionais. Foram registrados valores de repouso, contrações voluntárias máximas e contrações sustentadas. Os dados foram tabulados no Microsoft Excel e analisados estatisticamente no programa Statistica. Adotou-se um nível de significância de 5% (p≤0,05). Participaram do estudo 19 primigestas, com média de idade de 21,74±3,65 anos. Houve aumento da massa corporal no 3º trimestre gestacional em relação ao período pré-gestacional e diminuição da média do sinal dos músculos do assoalho pélvico durante o repouso ao longo das três avaliações. A musculatura abdominal diminuiu a média do sinal no repouso e durante a contração sustentada nas avaliações 2 e 3 comparadas à avaliação 1. Pode-se concluir que outros fatores, além dos relacionados ao aumento da massa corporal materna, podem estar associados à sobrecarga nos MAP durante a gestação logo no primeiro trimestre. Essa sobrecarga pode fazer que as gestantes apresentem um tônus muscular próximo ao limite superior de referência, alterando o padrão de atividade eletromiográfica principalmente no repouso, a fim de manter a função de sustentação dos órgãos pélvicos e de continência.

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“…During vaginal delivery, muscles of the levator hiatus are required to deform and stretch markedly. Using computer modeling, based on MRI, it has been found that some parts of the pubovisceral muscle stretch to 3.3 times their resting length during crowning of the head [29]. It is unlikely that the pelvic fl oor presents an absolute barrier to descent and delivery of the presenting part in any but a very small number of women.…”

Section: Discussionmentioning

confidence: 99%