Pelvic floor and abdominal muscle cocontraction in women with and without pelvic floor dysfunction: a systematic review and meta-analysis

Abstract

There is an ongoing discussion regarding abdominal muscle (AbM) and pelvic floor muscle (PFM) synergism. Therefore, this study aimed to investigate the cocontraction between AbMs and PFMs in women with or without pelvic floor dysfunction (PFD). The following databases were searched up to December 21, 2018: MEDLINE, EMBASE, LILACS, PEDro and CENTRAL. We included any study that assessed the cocontraction between PFMs and AbMs in women with and without PFD. Two reviewers independently screened eligible articles and extracted data. The outcomes were extracted and analyzed as continuous variables with random effect models. Twenty studies were included. A meta-analysis did not show differences in women with and without PFD. However, a sensitivity analysis suggested cocontraction of the transversus abdominis (TrA) during PFM contraction in healthy women (standardized mean difference (SMD) -1.02 [95% confidence interval (CI) -1.90 to -0.14], P=0.02; I2= not applicable; very low quality of evidence). Women with PFD during contraction of PFMs showed cocontraction of the obliquus internus (OI) (SMD 1.10 [95% CI 0.27 to 1.94], P=0.01; I2= not applicable; very low quality of evidence), and obliquus externus (OE) (SMD 2.08 [95% CI 1.10 to 3.06], P<0.0001; I2 = not applicable; very low quality of evidence). Increased cocontraction of the TrA may be associated with maximal contraction of PFMs in women without PFD. On the other hand, there is likely an increased cocontraction with the OI and OE in women with PFD.

Figure 1. Flowchart of the studies included in this review.

Figure 2. Risk of bias assessment. We considered “probably high risk of bias” as “definitely high risk of bias” (red color) and “probably low risk of bias” as “definitely low risk of bias” (green color).

Figure 3. Forest plot showing the co-activity of the transversus abdominis, rectus abdominis, obliquus internus and obliquus externus muscles during maximal pelvic floor muscle contraction. CI = Confidence interval; PFD = Pelvic floor dysfunction.

Figure 4. Sensitivity analysis of co-activity of transversus abdominis (without the Arab et al. 2011 study), rectus abdominis (without the Madill et al. (31)), obliquus internus (without the Madill et al. (31)) and obliquus externus (without the Madill et al. (31)) muscles when the pelvic floor muscles contract. CI = Confidence interval; PFD = Pelvic floor dysfunction.