To evaluate the influence of different modes of delivery on the incidence rate of stress urinary incontinence (SUI) and female pelvic floor anatomy.

From May to December 2008, a total of 49 cases from age of 18 to 35 with 28~36 gestational weeks were included into this study (study group). They were further divided into vaginal delivery group(n=24) and elective cesarean section(ECS) group(ECS group, n=22)according to the different modes of delivery. Meanwhile, another 20 healthy childless women of childbearing age were included into control group. The study protocol was approved by the Ethical Review Board of Investigation in Human Being of First Affiliated Hospital of Ji'nan University. Informed consent was obtained from all participants. Each subject received examination during rest and during Valsalva's maneuver for the following parameters: anteroposterior diameter (AP) and lateral diameter (LD) of levator hiatus (LH), posterior urethra-vesical angle (α), flexibility of bladder neck (θ), and distance between the pubic symphysis midpoint and bladder neck (D). The content of serum C-terminal propeptide of type Ⅰ procollagen (PICP) was detected by enzyme linked immunosorbent assay (ELISA) method. The above indicators were compared at 28 to 36 gestational weeks , 6 to 8 and 12 to 14 weeks after delivery between study group and control group.

The incidence of stress urinary incontinence reduced after delivery. For vaginal delivery group, the flexibility of bladder neck and distance between the pubic symphysis midpoint and bladder neck at 6 to 8 weeks after delivery had larger changes compared to ECS group (P<0.05). It also can be found significant difference in anteroposterior diameter and lateral diameter of pelvic reproductive levator hiatus (P<0.05). But there was no significant difference on the above parameters between two groups at 12 to 14 weeks after delivery. The content of serum C-terminal propeptide of type Ⅰ procollagen in vaginal delivery group was lower than that of ECS group during 6 to 8 weeks after delivery (P<0.05), but no significant difference during 12 to 14 weeks after delivery (P>0.05).

Pelvic tissue damages under elective cesarean section is less than that of vaginal delivery. Elective cesarean section has protective effects on pelvic structure. Pelvic damages under all methods of delivery are temporary, and it could be recovered by natural course. Serum procollagen peptide structural damage as the pelvic fibrosis serum markers, can indirectly from post-natal pelvic floor injury response to self-repair process of development. However, elective cesarean section has a limited protective effect on pelvic floor function.