When compared with the control group ( n = 29 ) , benefits to the intervention group ( n = 28 ) were observed in terms of fewer prolapse symptoms at 12months [ mean difference 3.94 ; 95 % confidence interval ( CI ) 1.35-6 .75 ; t = 3.24 , p = 0.006 ] ; however , these results must be viewed with caution due to possible selection bias .