TABLE 4.

EP data on pelvic floor muscles of women at 6–8 weeks after delivery; N = 1,516.

Pelvic floor muscle	Muscle strength a						Fatigue degree a
Type I	0	I	II	III	IV	V	0	<0
	15	875	440	159	27	0	212 (14.0%)	1,304 (86.0%)②
	1,330 (87.7%)①			186 (12.3%)
Type II	0	I	II	III	IV	V	0	<0
	3	282	336	661	222	12	1,364 (90.0%)	152 (10.0%)④
	621 (41.0%)③			895 (59.0%)
Vaginal dynamic pressure b	73.9 ± 14.3 (cmH2O)

^a The counting data are presented as the incidence rate (%, n/N), and the comparison was performed using chi-squared analysis.

^b The measurement data are presented as mean ± SD.

p < 0.05: ①vs.③; ①vs.④; ②vs.③; ②vs.④; ③vs.④.