Study design, materials and methods
There is a database of 58 adult females stress urinary incontinence patients, who had urodynamic study in the urodynamic Center of our Hospital from September 2014 to June 2016, the ethics and clinical trials committee at our institution approved this study, and patients who joined this study were all signed informed consent. Our study excluded patients whom: 1.got pelvic surgery 2. never had system diseases 3. had urinary tract infections. All patients who were included in our study must have a positive abdominal leak point pressure (ALPP) test and has a normal bladder function at the same time. And according to the Stamey scale, we divided the included methods into 3 groups: grade 1 group (n=11): urinary incontinence was associated with severely increased abdominal pressure (coughing, sneezing, activities); grade 2 group(n=39): urinary incontinence was associated with moderately increased abdominal pressure (walking, daily activities); grade 3 group(n=8): urinary incontinence was associated with mildly increased abdominal pressure (changing the body position). Urodynamic parameters: Multichannel urodynamic evolution was performed according to the International Continence Society (CIS) guidelines on urodynamic equipment performance. Our study also included a pressure flow study, which included information about abdominal leak point pressure (ALPP). And all urodynamic studies were done by one experienced urodynamic technician from urodynamic Center of our Hospital, and all urodynamic reports were interpreted by an experienced urologist.
Results
At first, according to the Stamey scale, we divided these included patients into 3 groups: grade1 group (n=11); grade2 group (n=39); grade3 group(n=8).A mean age of 67.6±12.3 years; a mean ALPP of 44.7±12 cmH2O. The correlations between first childbearing age, number of births and ALPP were tested by the Pearson and Spearman test. The analysis result showed that there is a negative correlation between the first childbearing age and the ALPP (r = -0.699, P < 0.05) (Figure 1).Meanwhile, the study also found that the first childbearing age and the number of births were not associated with the level of the Stamey score (r=0.259, P > 0.05), (0.347, P > 0.05) respectively, and the number of births was not associated with the level of ALPP(r=-0.007, P > 0.05).
Interpretation of results
Our study objective is to identify the correlation between abdominal leak point pressures (ALPP), Stamey score and the first childbearing age and number of births in the female adult patients with stress urinary incontinence (SUI). In our study, we can find that there is a negative correlation between the first childbearing age and the ALPP (r = -0.699, P < 0.05). Meanwhile, the study also found that the first childbearing age and the number of births were not associated with the level of the Stamey score (r=0.259, P > 0.05), (0.347, P > 0.05) respectively, and the number of births was not associated with the level of ALPP(r=-0.007, P > 0.05).Higher the first childbearing age is, worse the SUI symptoms is, and the patient’s ALPP also decreased, but the ability to control urine decreased. .The mechanisms may be that,as we know the female urethra is a short ,tubular structure measuring 3.8-5.0 cm in length. It extens from the bladder neck and courses caudally, with anterior obliquity, to the urinary meatus,and there is also some important ligaments( which can support the pelvic tissues ) and pelvic muscle tissues there. So during the delivery process ,the ligaments and pelvic muscle tissues may be injured by tensile force wich come from the delivery process,and with the childbearing age increased ,the injury risk also increased,finally this situation may lead to urinary incontience ,and as the childbearing age increased the serious degree increased too.