Diagnostic accuracy and cut-off points for vaginal manometry to differentiate between weak and strong pelvic floor muscle contraction in pregnant women

Background

Identifying a weak/strong pelvic floor muscle (PFM) contraction in pregnant women may help prevent and treat dysfunctions during late pregnancy and postpartum.

Objective

To determine whether the Peritron™ manometer can accurately differentiate a weak from a strong PFM contraction and the respective cut-offs for its variables in pregnant women.

Methods

This is a diagnostic accuracy study. Forty-four women in the third trimester of pregnancy participated (mean±SD age: 29±5 years). The reference test was vaginal palpation, and the index test was vaginal manometry (Peritron™ manometer). Variables assessed by vaginal manometry were rest, maximal voluntary contraction (MVC), MVC average, duration, gradient, area under the curve (AUCm), and contraction speed. The Receiver Operating Curve (AUC/ROC) was used to analyze the data and obtain cut-off points for these variables.

Results

Perfect discrimination (AUC=1.00) to differentiate between a weak/strong PFM contraction in pregnant women was observed for peak MCV (cut-off: 40.56 cmH₂O). The MVC average showed excellent discriminative ability (AUC=0.96; cut-off: 30.66 cmH₂O). The gradient variable (AUC=0.85; cut-off: 27.83 cmH₂O/s) and AUCm (AUC=0.86; cut-off: 1315.6 cm²*s) showed a good discriminative ability.

Conclusion

The best variables to discriminate between weak/strong PFM contraction in pregnant women using vaginal manometry were peak MVC, MVC average, gradient, and AUCm.