Table 3. Linear regression equations.

POP-Q point	Other point	No.	Linear regression equation	Pearson's r	Spearman's ρ	P-value
POP-Q point≥stage 1
Bp	C	405	C=0.506Bp+0.122	0.419		<0.001
C	Bp	402	Bp=0.348C+0.517	0.426		<0.001
POP-Q point≥stage 2
Bp	C	343	C=0.359Bp+1.148		0.523	<0.001
C	Bp	289	Bp=0.497C+1.584		0.637	<0.001
POP-Q point≥stage 3
Bp	C	133	C=0.389Bp+3.134		0.783	<0.001
C	Bp	158	Bp=0.435C+2.988		0.718	<0.001

POP-Q, pelvic organ prolapse quantification; Bp, posterior vaginal wall; C, apex.