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    Vaginal delivery and the pelvic floor: Outcomes of levator ani injury

     

    Prevention and recommendations

    Numerous studies have shown how vaginal delivery affects the pelvic floor negatively yet no data exist from clinical trials on effective methods of preventing levator ani injury. During vaginal delivery, pudendal blocks and epidural anesthesia may be protective against development of levator ani injuries. In mice, a 30% stretch was sufficient to cause injury to maximally activated (tensed) muscles, whereas a stretch of 50% was necessary to produce a similar injury in passive (relaxed) muscles.28 That would support the theory that anesthesia-induced relaxation of the pelvic floor allows for passive muscle stretch and, therefore, less injury.

    Factors including operative forceps delivery, length of second stage, and fetal size/head circumference should be identified and can be used when counseling patients both intrapartum and postpartum. Identifying antepartum and intrapartum factors that influence the risk of levator ani injury, such as fetal size/head circumference, length of second stage and the use of forceps, also can be useful when counseling patients and to minimize injury. Forceps should be used with caution and with appropriate anesthesia to allow the pelvic muscles adequate time to stretch with delivery.1,8

    Pelvic floor education and exercises during and after pregnancy may help prevent development of pelvic floor dysfunction. In one study, women who received pelvic floor therapy from 20 weeks’ gestation were 56% less likely to report urinary incontinence in late pregnancy, 50% less likely at 12 weeks postpartum, and 30% less like to report incontinence at 6 months postpartum.29 Similar results have been shown for treatment of urinary incontinence in pregnancy. While limited studies have shown that pelvic floor exercises have no effect on pelvic organ prolapse in the immediate postpartum period, studies have shown improvement in middle-aged women, suggests that further long-term research is necessary.30,31 Routine pelvic floor education or referral to pelvic floor physical therapy during the intrapartum and postpartum period may be beneficial, especially in high-risk patients.

    More practical techniques such as manual manipulation of the levator hiatus beginning in the third trimester may be beneficial and may change the biomechanical properties of the levator ani muscles.32 Manual massage or the Epi-No Birth Trainer (Starnberg Medical, Tecsana GMBH, Muenchen, Germany) can be used to stretch the perineum and vagina starting at 37 weeks’ gestation until delivery. In one randomized controlled trial, a trend toward reduction in levator ani avulsions (6% vs 13%) was found with use of the Epi-No device versus no intervention starting at 37 weeks’ gestation, but that did not achieve statistical significance.32

    Summary

    Numerous studies have shown that vaginal delivery affects the pelvic floor negatively. Scientific evidence is insufficient, however, to suggest that routine elective cesarean section should be advocated for levator ani risk reduction. Elective cesarean section carries substantial risks and disadvantages to both mother and baby,1 and these risks likely outweigh the risk of childbirth-related levator injury.8,9 Ways to identify women and labor scenarios that represent high risk of levator injury need to be developed and refined, such that appropriate nonsurgical risk-reducing pregnancy and labor interventions can be studied adequately.

    Furthermore, new methods for identifying women at high risk for postsurgical prolapse recurrence need to be refined, such that appropriate, durable surgical interventions can be investigated and stratified by levator structural status.

     

    References

    1. Dietz HP. Pelvic Floor trauma in childbirth. Aust N Z J Obstet Gynaecol. 2013;53:220-230.

    2. DeLancey JO. The hidden epidemic of pelvic floor dysfunction: achievable goals for improved prevention and treatment. Am J Obstet Gynecol. 2005;192:1488–1495.

    3. Barber MD. Contemporary Views of Female Pelvic Anatomy. Cleve Clin J Med. 2005;72 Suppl 4:S3–11.

    4. Lien KC, Mooney B, Delancey JO, Ashton-Miller JA. Levator ani muscle stretch induced by simulated vaginal birth. Obstet. Gynecol. 2004;103(1):31–40.

    5. Ashton-Miller JA, and DeLancey JOL. Functional Anatomy of the Female Pelvic Floor. Annals of the New York Academy of Sciences. 2007;1101: 266–296.

    6. DeLancey JO, Kearney R, Chou Q, Speights S, Binno. The appearance of levator ani muscle abnormalities in magnetic resonance images after vaginal delivery. Obstet Gynecol. 2003;101:46–53.

    7. Deitz HP, Simpson JM. Levator trauma is associated with pelvic organ prolapse. BJOG. 2008;115:979–984.

    8. Dietz HP, Lanzarone V. Levator trauma after vaginal delivery. Obstet Gynecol. 2005;106:707–712.

    9. Shek Kl, Dietz HP. The effect of Childbirth on hiatal dimensions. Obstet Gynecol. 2009;113:1272–1278.

    10. Rortveit G, Daltveit AK, Hannestad YS, Hunskaar S. Urinary incontinence after vaginal delivery or cesarean section. N Engl J Med. 2003;348:900–907.

    11. van Delft K, Sultan AH, Thakar R, Schwertner-Tiepelmann N, Kluivers K. The relationship between postpartum levator ani muscle avulsion and signs and symptoms of pelvic floor dysfunction. BJOG. 2014;121:1164–1172.

    12. van Delft KWM, Thakar R, Sultan AH, IntHout J, Kluivers KB. The natural history of levator avulsion one year following childbirth: a prospective study. BJOG. 2015;122:1266–1273.

    13. DeLancey JO. Anatomy and biomechanics of genital prolapse. Clin Obstet Gynecol. 1993;36:897–909.

    14. Shek Kl, Dietz HP. Can levator avulsion be predicted antenatally? Am J Obstet Gynecol. 2010;202:e1–6.

    15. Luber KM, Boero S, Choe JY. The demographics of pelvic floor disorders: current observations and future projections. Am J Obstet Gynecol. 2001;184:1496–503

    16. Deitz HP. Charntarason V, Shek KL. Levator avulsion is a risk factor for cystocele recurrence. Ultrasound Obstet Gynecol. 2010;36:76–80

    17. Wong V, Shek KL, Goh J, Rane A, Deitz HP. Is levator avulsion a predictor of recurrence after anterior compartment mesh? Neurourol Urodyn. 2011;30:879–880.

    18. Singh K, Jakab M, Reid W, Berger L, Hoyte L. Three-dimensional magnetic resonance imaging assessment of levator ani morphologic features in different grades of prolapse. Am J Obstet Gynecol. 2003;188:910–915.

    19. Hoyte L, Damase MD, Warfield S, et al. Quantity and distribution of levator ani stretch during simulated vaginal childbirth. Am J Obstet Gynecol. 2008; 199:e1-e5.

    20. DeLancey JO, Morgan DM, Fenner DE, Kearney R, Guire K, Miller JM, et al. Comparison of levator ani muscle defects and function in women with and without pelvic organ prolapse. Obstet Gynecol. 2007;109:295–302.

    21. Dietz HP, Simpson JM. Does delayed child-bearing increase the risk of levator injury in labour?. Aust N Z J Obstet Gynaecol. 2007;47:491–495.

    22. Thibault-Gagnon S, Yusuf S, Langer S, et al. Do women notice the impact of childbirth-related tevator trauma on pelvic floor and sexual function? Int Urogynecol J. 2012;23: S183–S185.

    23. DeLancey JO, Trowbridge ER, Miller JM, et al. Stress urinary incontinence: relative importance of urethral support and urethral closure pressure. J Urol. 2008; 79:2286–2290.

    24. Dietz HP, Kirby A. Modelling the likelihood of levator avulsion in a urogynaecological population. Aust N Z J Obstet Gynaecol. 2010;50:268–272.

    25. Dietz HP, Kirby A, Shek KL, Bedwell PJ. Does avulsion of the puborectalis muscle affect bladder function? Int Urogynecol J Pelvic Floor Dysfunct 2009;20:967–972.

    26. Lewicky-Gaupp C, Brincat C, Yousuf A, Patel DA, Delancey JO, Fenner DE. Fecal incontinence in older women: are levator ani defects a factor? Am J Obstet Gynecol. 2010;202:491.e1–6.

    27. Brooks SV, Zerba E, Faulkner JA. Injury to muscle fibres after single stretches of passive and maximally stimulated muscles in mice. J Physiol 1995;488:459–469.

    28. Hay-Smith J, Mørkved S, Fairbrother KA, Herbison GP. Pelvic floor muscle training for prevention and treatment of urinary and faecal incontinence in antenatal and postnatal women. Cochrane Database of Systematic Reviews 2008, Issue 4.

    29. Hagen S, Stark D. Conservative prevention and management of pelvic organ prolapse in women. Cochrane Database Syst Rev. 2011;(12):CD003882.

    30. Bø K, Hilde G, Stær-Jensen J, Siafarikas F, Tennfjord MK, Engh ME. Postpartum pelvic floor muscle training and pelvic organ prolapse--a randomized trial of primiparous women. Am J Obstet Gynecol. 2015;212(1):38.e1-7.

    31. Shek KL, Langer S, Chantarasorn M, Dietz HP. Does the Epi-No prevent levator trauma? A randomised controlled trial. Neurourol Urodyn. 2010;29:1021–1022.

    Lennox Hoyte, MD, MSEECS
    Dr Hoyte is Professor, Fellowship and Division director, Female Pelvic Medicine and Reconstructive Surgery, University of South Florida ...
    Allison M Wyman, MD
    Dr Wyman is Clinical Fellow, Female Pelvic Medicine and Reconstructive Surgery, University of South Florida Morsani College of Medicine, ...
    Lindsey A Hahn, DO
    Dr Hahn is Clinical Fellow, Female Pelvic Medicine and Reconstructive Surgery, University of South Florida Morsani College of Medicine, ...

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    • This article comes disturbingly close to encouraging women to elect Caesarian section in order to avoid pelvic floor trauma. I seriously question the idea that a forceps delivery carried out by a skilled operator leads to an increased risk of injury. ACOG's advice to require a nullip to push for 3 full hours before employing forceps is where the real problem lies. At the end of those 3 hours, the vulva, having been subjected to unrelenting pushing, is swollen to a point where tearing rather than stretching is the likely outcome. It's only reasonable to conclude that the same dynamic applies to the levator muscles. Moreover, this prolonged pushing results in distortion of the fetal fontanelles, making proper forceps application difficult and injury more likely. Dr.Joseph DeLee's classic paper, "The Prophylactic Forceps Operation" of 1920 stated correctly that this technique preserved the integrity of the pelvic floor. That was the case then and is the case today. Sadly, forceps delivery is no longer taught, which why we need so many specialists in pelvic floor reconstruction.
    • RuthMielke
      Agree with the first statement re: "coming close to recommending ECD". As a certified nurse-midwife in clinical practice for 30 years who has worked in very high volume labor settings, I challenge the statistic cited by the authors "More than 30% of all women who deliver vaginally will experience some form of direct trauma to the pelvic floor resulting in injury to their levator ani muscle". Levator ani injury: damage to said muscle - either a third degree or fourth degree perineal laceration occurs rarely- not 3 out of 10 vaginal births. There is a dearth of research that routine use of episiotomy is correlated with greater levator ani injury - Why wasn't this mentioned? Also - challenge the suggestion that pudendal/regional anesthesia may promote pelvic relaxation and prevent injury. Regional anesthesia is well-known to be associated with prolonged second stage as compared to women without it and therefore the "relaxation" hypothesis is obviated by the resulting prolonged period of perineal distention that often results. I appreciated the excellent anatomical explanation/images but wish the authors gave more consideration to actual practice e.g. < 0.5% 3rd/4th degree lacerations which I would say is typical practices if routine episiotomy is not done, and focused more on aspects of prevention that were only touched on - pelvic floor strengthening prenatally and during interconception, pre-pregnancy attention to high BMI, as such women have more genital tract trauma and larger babies etc.
    • ROBERTCWALLACH
      nicely done; better discussion than found in most texts; disappointed that seminal article by Porges,Porges, Blinick in the green journal has disappeared

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