Skip to main content
SpringerLink
Log in

Morphological Variation in the Pelvic Floor Muscle Complex of Nulliparous, Pregnant, and Parous Women

  • Original Article
  • Published:
Annals of Biomedical Engineering Aims and scope Submit manuscript

Abstract

Specific levator ani muscle imaging measures change with pregnancy and vaginal parity, though entire pelvic floor muscle complex (PFMC) shape variation related to pregnancy-induced and postpartum remodeling has never been quantified. We used statistical shape modeling to compute the 3D variation in PFMC morphology of reproductive-aged nulliparous, late pregnant, and parous women. Pelvic magnetic resonance images were collected retrospectively and PFMCs were segmented. Modes of variation and principal component scores, generated via statistical shape modeling, defined significant morphological variation. Nulliparous (have never given birth), late pregnant (3rd trimester), and parous (have given birth and not currently pregnant) PFMCs were compared via MANCOVA. The overall PFMC shape, mode 2, and mode 3 significantly differed across patient groups (p < 0.001, = 0.002, = 0.001, respectively). This statistical shape analysis described greater perineal and external anal sphincter descent, increased iliococcygeus concavity, and a proportionally wider mid-posterior levator hiatus in late pregnant compared to nulliparous and parous women. The late pregnant group was the most divergent, highlighting differences that likely reduce the mechanical burden of vaginal childbirth. This robust quantification of PFMC shape provides insight to pregnancy and postpartum remodeling and allows for generation of representative non-patient-specific PFMCs that can be used in biomechanical simulations.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Figure 1
Figure 2
Figure 3
Figure 4

Similar content being viewed by others

Abbreviations

PFMC:

Pelvic floor muscle complex

References

  1. Alperin, M. Impact of pregnancy and delivery on pelvic floor biomechanics. In: Biomechanics of the Female Pelvic Floor. Elsevier Inc., 2016, pp. 229–238. https://doi.org/10.1016/B978-0-12-803228-2.00010-6

  2. Alperin, M., T. Kaddis, R. Pichika, M. C. Esparza, and R. L. Lieber. Pregnancy-induced adaptations in intramuscular extracellular matrix of rat pelvic floor muscles. Am. J. Obstet. Gynecol. 215:210.e1-210.e7, 2016.

    Article  PubMed  Google Scholar 

  3. Alperin, M., D. M. Lawley, M. C. Esparza, and R. L. Lieber. Pregnancy-induced adaptations in the intrinsic structure of rat pelvic floor muscles. Am. J. Obstet. Gynecol. 213:191.e1-191.e7, 2015.

    Article  PubMed  Google Scholar 

  4. Benjamini, Y., and Y. Hochberg. Controlling the false discovery rate: a practical and powerful approach to multiple testing. J. R. Stat. Soc. B. 57:289–300, 1995.

    Google Scholar 

  5. Bône, A., M. Louis, B. Martin, and S. Durrleman. Deformetrica 4: An Open-Source Software for Statistical Shape Analysis, 2018.

  6. Catanzarite, T., S. Bremner, C. L. Barlow, L. Bou-Malham, S. O’Connor, and M. Alperin. Pelvic muscles’ mechanical response to strains in the absence and presence of pregnancy-induced adaptations in a rat model. Am. J. Obstet. Gynecol. 218:512.e1-512.e9, 2018.

    Article  PubMed  Google Scholar 

  7. Cates, J. Shape modeling and analysis with entropy-based particle systems. University of Utah, 2010.

    Google Scholar 

  8. Davidson, M. J., P. M. F. Nielsen, A. J. Taberner, and J. A. Kruger. Change in levator ani muscle stiffness and active force during pregnancy and post-partum. Int. Urogynecol. J. 2020. https://doi.org/10.1007/s00192-020-04493-0.

    Article  PubMed  Google Scholar 

  9. DeLancey, J. O. L. L., R. Kearney, Q. Chou, S. Speights, and S. Binno. The appearance of levator ani muscle abnormalities in magnetic resonance images after vaginal delivery. Obst. Gynecol. 101:46–53, 2003.

    Google Scholar 

  10. Fishbaugh, J., S. Durrleman, M. Prastawa, and G. Gerig. Geodesic shape regression with multiple geometries and sparse parameters. Med. Image Anal. 39:1–17, 2017.

    Article  PubMed  PubMed Central  Google Scholar 

  11. Goparaju, A., I. Csecs, A. Morris, E. Kholmovski, N. Marrouche, R. Whitaker, and S. Elhabian. On the evaluation and validation of off-the-shelf statistical shape modeling tools: a clinical application. Shape Med. Imaging. 11167:14–27, 2018.

    Article  Google Scholar 

  12. Handa, V. L., J. L. Blomquist, L. R. Knoepp, K. A. Hoskey, K. C. McDermott, and A. Muñoz. Pelvic floor disorders 5–10 years after vaginal or cesarean childbirth. Obst. Gynecol. 118:777, 2011.

    Article  Google Scholar 

  13. Jean Dit Gautier, E., O. Mayeur, J. Lepage, M. Brieu, M. Cosson, and C. Rubod. Pregnancy impact on uterosacral ligament and pelvic muscles using a 3D numerical and finite element model: preliminary results. Int. Urogynecol. J. 29:425–430, 2018.

    Article  PubMed  Google Scholar 

  14. Kamisan Atan, I., B. Gerges, K. L. Shek, and H. P. Dietz. The association between vaginal parity and hiatal dimensions: a retrospective observational study in a tertiary urogynaecological centre. BJOG. 122:867–872, 2015.

    Article  CAS  PubMed  Google Scholar 

  15. Lee, S.-L., E. Tan, V. Khullar, W. Gedroyc, A. Darzi, and G.-Z. Yang. Physical-based statistical shape modeling of the levator ani. IEEE Trans. Med. Imaging. 28:926–936, 2009.

    Article  PubMed  Google Scholar 

  16. Mant, J., R. Painter, and M. Vessey. Epidemiology of genital prolapse: observations from the oxford family planning association study. BJOG. 104:579–585, 1997.

    Article  CAS  Google Scholar 

  17. Oliphant, S., T. Canavan, S. Palcsey, L. Meyn, and P. Moalli. Pregnancy and parturition negatively impact vaginal angle and alter expression of vaginal MMP-9. Am. J. Obstet. Gynecol. 218:242.e1-242.e7, 2018.

    Article  PubMed  Google Scholar 

  18. Polly, P. D. Geometric morphometrics for mathematica, 2019. https://pollylab.indiana.edu/software/

  19. Routzong, M., P. Moalli, G. Rostaminia, and S. Abramowitch. Statistical shape modeling of nulliparous, pregnant, and parous female pelvic floor muscle complexes. Mendeley Data. 2022. https://doi.org/10.17632/75vnsc24wk.1

    Article  Google Scholar 

  20. Routzong, M. R. Computational modeling of variations in female anatomy to elucidate biomechanical mechanisms of pelvic organ and tissue functions. University of Pittsburgh, 2021. http://d-scholarship.pitt.edu/41420/

  21. Routzong, M. R., C. Chang, R. P. Goldberg, S. D. Abramowitch, and G. Rostaminia. Urethral support in female urinary continence part 1: dynamic measurements of urethral shape and motion. Int. Urogynecol. J. 2021. https://doi.org/10.1007/s00192-021-04765-3.

    Article  PubMed  Google Scholar 

  22. Routzong, M. R., L. C. Martin, G. Rostaminia, and S. Abramowitch. Urethral support in female urinary continence part 2: a computational, biomechanical analysis of Valsalva. Int. Urogynecol. J. 2021. https://doi.org/10.1007/s00192-021-04694-1.

    Article  PubMed  Google Scholar 

  23. Routzong, M. R., G. Rostaminia, S. T. Bowen, R. P. Goldberg, and S. D. Abramowitch. Statistical shape modeling of the pelvic floor to evaluate women with obstructed defecation symptoms. Comput. Methods Biomech. Biomed. Eng. 24:1–9, 2020.

    Google Scholar 

  24. Routzong, M. R., G. Rostaminia, P. A. Moalli, and S. D. Abramowitch. Pelvic floor shape variations during pregnancy and after vaginal delivery. Comput. Methods Programs Biomed. 194:105516, 2020.

    Article  PubMed  Google Scholar 

  25. Samuelsson, E., L. Ladfors, B. G. Lindblom, and H. Hagberg. A prospective observational study on tears during vaginal delivery: occurrences and risk factors. Acta Obstet. Gynecol. Scand. 81:44–49, 2002.

    Article  PubMed  Google Scholar 

  26. Shek, K. L., J. Kruger, and H. P. Dietz. The effect of pregnancy on hiatal dimensions and urethral mobility: an observational study. Int. Urogynecol. J. 23:1561–1567, 2012.

    Article  PubMed  Google Scholar 

  27. Siafarikas, F., J. Stær-Jensen, G. Hilde, K. Bø, and M. Ellström Engh. Levator hiatus dimensions in late pregnancy and the process of labor: a 3- and 4-dimensional transperineal ultrasound study. Am. J. Obstet. Gynecol. 210:4841–4847, 2014.

    Article  Google Scholar 

  28. Siafarikas, F., J. Stær-Jensen, G. Hilde, K. Bø, and M. Ellström Engh. The levator ani muscle during pregnancy and major levator ani muscle defects diagnosed postpartum: a three- and four-dimensional transperineal ultrasound study. BJOG. 122:1083–1091, 2015.

    Article  CAS  PubMed  Google Scholar 

  29. Van Geelen, H., D. Ostergard, and P. Sand. A review of the impact of pregnancy and childbirth on pelvic floor function as assessed by objective measurement techniques. Int. Urogynecol. J. 29:327–338, 2018.

    Article  PubMed  Google Scholar 

Download references

Acknowledgments

We acknowledge Vincenzia Vargo and Shaniel Bowen for their contributions to the PFMC segmentations, the Korea Institute of Science and Technology Information for access to the Visible Korean Human data used to generate the female PFMC template, and the University of Pittsburgh Center for Research Computing advanced computing resources used to complete this study. This material is based upon work supported by the National Science Foundation Graduate Research Fellowship Program under Grant #1747452. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Data Availability

The statistical shape modeling code used in this study can be accessed as part of the first author’s doctoral dissertation.20 The overall average PFMC geometry; the average nulliparous, late pregnant, and parous PFMC geometry files; and all PC scores associated with this study can be accessed via Mendeley Data.19

Author information

Authors and Affiliations

  1. Department of Bioengineering, University of Pittsburgh, 3700 O’Hara Street, 406 Benedum Hall, Pittsburgh, PA, 15260, USA

    Megan R. Routzong & Steven D. Abramowitch

  2. Department of Obstetrics, Gynecology & Reproductive Surgery, Magee-Womens Research Institute, University of Pittsburgh, Pittsburgh, PA, USA

    Pamela A. Moalli

  3. Female Pelvic Medicine and Reconstructive Surgery (FPMRS), Division of Urogynecology, University of Chicago Pritzker School of Medicine, Northshore University HealthySystem, Skokie, IL, USA

    Ghazaleh Rostaminia

Authors
  1. Megan R. Routzong
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Pamela A. Moalli
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Ghazaleh Rostaminia
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Steven D. Abramowitch
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Steven D. Abramowitch.

Additional information

Associate Editor Ender Finol oversaw the review of this article.

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Routzong, M.R., Moalli, P.A., Rostaminia, G. et al. Morphological Variation in the Pelvic Floor Muscle Complex of Nulliparous, Pregnant, and Parous Women. Ann Biomed Eng 51, 1461–1470 (2023). https://doi.org/10.1007/s10439-023-03150-z

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s10439-023-03150-z

Keywords

Search

Navigation