Age, parity, and prolapse: interaction and influence on levator bowl volume

Int Urogynecol J. 2022 Dec;33(12):3415-3422. doi: 10.1007/s00192-022-05203-8. Epub 2022 May 3.


Introduction and hypothesis: The objective was to test the hypotheses that a linear relationship exists between age and levator bowl volume (LBV); and that age, parity, and prolapse are independently associated with LBV.

Methods: We conducted a secondary analysis of data from nulliparous women, parous controls, and prolapse (Pelvic Organ Prolapse Quantification (POP-Q) Ba ≥ 1 cm) cases from each of three age groups: young (≤40), mid-age (50-60), and older (≥70). LBV was measured using MRI at rest and Valsalva as the 3D space contained above the levator ani muscles and below the sacrococcygeal junction-to-inferior pubic point reference plane. Linear regression models were used to examine the effects of age, parity, prolapse, and their interactions (age*parity and age*prolapse) on LBV.

Results: Each group consisted of 9-12 women. LBVRest increased with age in a nonlinear fashion. For nulliparous women, the median value increased 4.7% per decade from the young to mid-age group and 84% per decade from the mid-age to older group; for parous controls, the corresponding increases were 38% and -0.5%; and for women with prolapse, they were 46% and 11%. Age and prolapse status (both p<0.001) were found to be significant independent predictors of LBVRest. Interactions between age*prolapse (p=0.003) and age*parity (p=0.045) were also independently associated with LBVRest.

Conclusions: Parity and prolapse influence how age affects LBVRest. In nulliparous women, age had little effect on LBVRest until after mid-age. For women with prolapse, LBVRest increased at a much earlier age, with the biggest difference occurring between young and mid-age women.

Keywords: Aging; Hiatus; Levator bowl volume; Parity; Prolapse.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Female
  • Humans
  • Magnetic Resonance Imaging
  • Parity
  • Pelvic Floor* / diagnostic imaging
  • Pelvic Organ Prolapse* / diagnostic imaging
  • Pregnancy
  • Ultrasonography