Results
Our study screened successfully in total 3385 subjects, including 1286
cases in CD group and 2099 cases in VD group. No significant differences
were detected in age, BMI, gestational age at delivery, and neonatal
weight between CD and VD (P > 0.05, table 1). Our analysis
showed that the average peak
amplitude of phasic (flick) contractions and the average mean amplitude
of tonic contractions were both significantly higher in CD than in VD (P
< 0.01, table 2). In
contrast, CD had less the mean amplitude variability of tonic
contractions than VD (P < 0.01, table 2). The results revealed
that the muscle strength of fast muscle (class II fibers) and slow
muscle (class I fibers) were higher in CD than in VD, and the variation
of slow muscle (class I fibers) was significantly higher in the VD. For
the comparison of the value at rest pre-baseline and post-baseline, CD
had higher average mean amplitude compared to VD(P<0.01, table 2). It
suggested that the PFM tension in a relaxed state were higher in CD than
in VD. Our results showed that the engagement of the abdominal muscles
in VD was significantly higher than that in CD(P<0.01, table 2).
We further differentiated as 4 subgroups of vaginal delivery. There was
no statistically difference in maternal age, BMI, gestational age at
delivery, and neonatal weight among the four subgroups of vaginal
delivery (P > 0.05, Table 3). We identified the significant
difference among the four subgroups of vaginal delivery group(Table
4). The
average mean amplitude of rest
pre-baseline was significantly higher in group B compared to group D
(P=0.041, Fig.1). The average peak amplitude of phasic (flick)
contractions (Fig.2) and the
average mean amplitude of tonic
contractions (Fig.3) in group D was statistically lower than the other
vaginal delivery groups (P<0.05). The
mean amplitude variability of
tonic contractions was larger in group D than group A, B. (P was
0.002,0.003, respectively, Fig.4). The average mean amplitude of rest
post-baseline was shorter in group D than groups A, B, and C (P was
0.000,0.000,0.003, respectively, Fig.5). There was no significantly
difference in the engagement of the abdominal muscles among 4 subgroups
of vaginal delivery(P > 0.05, Table 4).