Appearance of the levator ani muscle in pregnancy as assessed by 3-D MRI

Muriel K. Boreham, Michael V. Zaretsky, Marlene M. Corton, James M. Alexander, Donald D. McIntire, Diane M. Twickler

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Objective: The purpose of this study was to describe levator ani (LA) anatomy in postterm nulliparas using 3-dimensional (3-D) magnetic resonance (MR). Study design: Nulliparas (n = 84) with uncomplicated, postterm pregnancies underwent an MR (4 mm slices, 0 gap) of the uterus and pelvis. LA volume and morphometry were assessed using 3-D post-processing software. Results: LA insertion into the symphysis was visible in 93%, and the iliococcygeus muscle assumed a convex shape (arch) in the 92% of the 84 women. The LA shape was characterized as "U" in 53% and "V" in 47%. Mean LA volume was 13.5 (3.7) cm3. There was a positive association between LA volume and higher fetal station (P = .02) and increasing BMI (P < .001). However, no relationship between LA volume and station was found after adjusting for BMI. Conclusion: BMI was correlated with LA volume in postterm nulliparas. LA insertion into the symphysis and the iliococcygeus arch were well-preserved overall and morphometry was variable.

Original languageEnglish (US)
Pages (from-to)2159-2164
Number of pages6
JournalAmerican journal of obstetrics and gynecology
Issue number6
StatePublished - Dec 1 2005


  • Levator ani
  • Levator hiatus
  • Magnetic resonance imaging
  • Nulliparous

ASJC Scopus subject areas

  • Obstetrics and Gynecology


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