Pregnancy is the main risk factor contributing to the weakening of the pelvic floor muscle. Commonly encountered physiological changes during pregnancy, particularly changes in the urogenital system, increase the pressure and trauma of the expanding uterus and the foetal weight on the pelvic floor muscle throughout pregnancy together with changing hormonal levels during pregnancy, for e.g., ncreased progesterone level, decreased oestrogen, relaxin and collagen levels (Mikhail & Anyaegbunam 1995, Kristiansson et al. 2001). As relaxin levels decrease, the
urethral pressure and urethral epithelium may also decrease. As a result of these changes, the strength, supportive and sphincteric functions of the pelvic floor muscles may be inhibited (Allen et al.1990, Davis & Kumar 2003). The weakness of the pelvic floor muscles causes incompetence of urethral sphincter and bladder neck. In addition, the foetal weight in the uterus places direct pressure on the bladder which may lead to decreased bladder capacity but increase intravesicle pressure. Therefore, an increase in intra-abdominal pressure during coughing, sneezing, laughing or moving, etc., and when the intravesicle pressure exceeds the pressure of the urethral closure, then the urine will leak. All these
factors may contribute to SUI during pregnancy (Chaliha et al.2000).