Table 3. The ultrasound PFD results and IRD values for the postpartum group.

No.	Pelvic floor function	IRD resting (mean ± SD, mm)	IRD head-lift (mean ± SD, mm)
19	Normal	28.1±10.5	24.2±8.2
30	1 compartment involved*	27.2±9.5	23.6±9.6
23	2 compartments involved**	28.0±10.6	23.8±9.7
30	3 compartments involved***	29.3±8.7	25.6±6.5

*: an abnormal ultrasound result was found in only one compartment, e.g., bladder neck <10 mm below the line of reference or the lowest point of the cervix ≤15 mm above the line of reference or rectal ampulla ≥15 mm below the line of reference. **: an abnormal ultrasound result was found in 2 compartments. ***: an abnormal ultrasound result was found in 3 compartments. Statistical method: Spearman’s correlation coefficient. IRD, inter-rectus distance; PFD, pelvic floor dysfunction.