Myer ENB, et al. - Researchers evaluated the change in pelvic floor muscle strength in parous women over time. They also identified maternal and obstetric characteristics associated with the rate of change. A minimal increase in the pelvic muscle strength over time with an average change of 1.2 cm H20 per 5 years was seen among parous women. Authors noted an association between the change in strength and mode of delivery as well as obesity.

Methods

• In this IRB approved prospective cohort study of parous women, participants were recruited 5-10 years after first delivery and followed annually.
• Experts measured the pelvic floor muscle strength (peak pressure with voluntary contraction) at 2 annual visits approximately 4 years apart, using the Peritron perineometer.
• They calculated the change in peak pressures, standardized per 5-year interval.
• To identify maternal and obstetrical characteristics related to the rate of change in peak pressure, linear regression was used.
• Delivery group was the obstetrical variable of greatest interest.
• They clasified the participants into 3 delivery groups (considering all deliveries for each multipara).
• Cesarean-only, at least one vaginal birth but no forceps-assisted deliveries, and at least one forceps-assisted vaginal birth were included in the delivery categories.
• They completed the statistical analysis with STATA (StataCorp 2015, version 14 SE, College Station, TX).

Results

• Findings suggested that 2 perineometer measurements were completed by 543 participants with a median 4 years between measures (IQR, 3.1, 4.8).
• Data demonstrated that at initial measurement, women were, on average, 40 years old and 8 years from first delivery.
• In participants who delivered all their children by cesarean (38.5 cmH2O), initial strength was higher vs to women with any vaginal non-forceps delivery (26.0 cmH2O) or vaginal forceps delivery (13.5 cmH2O) (p < 0.001).
• As per the results, the first and second perineometry measurement demonstrated a strong correlation (r=0.84).
• In pelvic floor muscle strength, median change was small at 1.2 cmH2O per 5 years (IQR, -5.6, 9.9 cmH2O).
• Authors noted in multivariable that analysis, women who delivered by cesarean-only showed almost no change in strength over 5 years (0.2 increase cmH2O per 5 years) while those who experienced at least one vaginal or vacuum delivery increased strength (4.8 cmH2O per 5 years) as did women with at least one forceps delivery (5.0 cmH20 per 5 years).
• Moreover, compared to normal weight participants (0.2 cmH2O per 5 years), a significant reduction in strength was demonstrated by obese women (-3.1 cmH2O per 5 years).