Table 1. Sample size calculation.

Risk actors	% of case with exposure (p2)	% of control with exposure (p1)	Power	CI (%)	AOR	Sample size
Age >44	71.8	27.1	80	95	6.8	55
Formal education	85	58	80	95	4.3	111
Parity	64.5	26.67	80	95	4.5	69
Sphincter damage	15.2	2	80	95	8	173
Carrying heavy object	67.4	40	80	95	3.1	131
Family history of POP	22.6	6.2	80	95	4.9	176
Underweight	34.5	14	80	95	3.2	164
Delivery assisted by non-health personnel	63.4	39.1	80	95	2.6	167