How does ageing affect the pelvic floor muscles? A systematic review and meta–analysis

Skeletal muscle ageing is characterized by distinct histomorphological changes. The aim of this review is to describe these changes in the pelvic floor muscles, which differ from other striated muscles in several key aspects. Special attention is given to the changes in muscle structure and function during ageing in women with pelvic organ prolapse. Five databases were searched for this review: PubMed/Medline, Embase, Scopus, Web of Science, and Google Scholar. The PRISMA protocol for systematic reviews was strictly followed. The quality of the studies was assessed using the Newcastle–Ottawa Scale. Two cross-sectional studies were eligible for meta-analysis, both with low risk of bias. The primary outcome was intramuscular collagen content in pelvic floor muscles. A pooled exploratory analysis of the three muscle‑specific estimates yielded a mean increase of 3.65% in intramuscular collagen content across pelvic floor muscles overall. Additional histological changes were described, but could not be quantitatively synthesized due to insufficient comparable data. Ageing is associated with an increase in intramuscular collagen in pelvic floor muscles. However, based on the available data, it remains unclear whether pelvic floor muscle ageing differs between healthy women and those with pelvic organ prolapse. Further research with larger, well-controlled studies is needed to better understand the relationship between muscle ageing and pelvic organ prolapse.