At What Point in the Menstrual Cycle Are the Pelvic Floor Muscles at Their Weakest?

Pelvic floor muscle (PFM) strength is a critical factor for optimal pelvic floor function. Fluctuations in strength values based on different phases of the menstrual cycle (MC) could signify a need for a paradigm shift in evaluating, approaching, and planning training. This research aims to examine and contrast the pelvic floor muscle strength during different phases of the menstrual cycle. A prospective observational study employing digital assessment with the modified Oxford scale and vaginal dynamometry measurements was performed, in order to assess the baseline strength and the contraction strength of the PFMs in eumenorrheic females at three different phases of the MC: the early follicular phase (EFP), the late follicular phase (LFP), and the mid-luteal phase (MLP). During two complete cycles, tympanic temperature and body weight were measured and the urinary luteinizing hormone concentration was tested to determine the time of ovulation. In total, 216 dynamometric measurements of PFM strength were obtained from eighteen nulliparous women (25.72 ± 5.03 years). There were no differences between the baseline strength (p = 0.886) and the contraction strength (p = 0.756) with the dynamometric speculum. In the post hoc analysis, the baseline strength, contraction strength, and strength showed no significant differences between MC phases. As no differences in PFM strength in women were found, the PFMs do not seem to be weaker at any time during the menstrual cycle. It appears that the assessment, establishment, and monitoring of a PFM training program could be initiated at any point in the cycle.