通过盆底超声检查观察二次自然分娩后产妇近期盆底结构变化。

选取从2016年10月至2017年10月在浙江省立同德医院产后42 d复查的二次自然分娩和初次自然分娩产妇各50例。盆底超声检查观察所有产妇膀胱颈活动度（BND）、最大Valsalva状态时膀胱后角、膀胱颈倾斜角、膀胱颈旋转角、肛提肌裂孔面积，以及尿道内口漏斗化、会阴体活动过度、子宫下垂和直肠膨出发生情况。采用组间配对t检验比较初次自然分娩组与二次自然分娩组产妇BND、最大Valsalval状态时膀胱后角、膀胱颈倾斜角、膀胱颈旋转角、肛提肌裂孔面积。采用χ²检验子宫下垂、直肠膨出、尿道内口漏斗化、会阴体活动过度发生率。

二次自然分娩组产妇BND、最大Valsalval状态时膀胱后角、膀胱颈倾斜角、膀胱颈旋转角、肛提肌裂孔面积均较初次自然分娩组产妇增大[（29.37±5.32）mm vs （22.63±6.35）mm，（148.8±14.97）^° vs（141.2±15.20）^°，（73.69±16.03）^° vs （69.8±15.25）^°，（44.41±19.27）^° vs（40.0±17.52）^°，（21.47±5.19）cm² vs （19.15±4.10）cm²]，且差异均有统计学意义（t=5.761，P<0.001；t=2.519，P=0.001，t=2.476，P=0.001；t=3.123；P=0.001；t=2.481，P<0.001）。二次自然分娩组产妇子宫下垂、尿道内口漏斗化、会阴体活动过度发生率均高于初次自然分娩组产妇[46.0%（23/50）vs 20.0%（10/50），12.0%（6/50）vs 6.0%（3/50），20.0%（10/50）vs 6.0%（3/50）]，且差异均有统计学意义（χ²=7.644，P=0.006；χ²=3.342，P=0.043；χ²=4.332，P=0.037），二次自然分娩组与初次自然分娩组产妇直肠膨出发生率差异无统计学意义[4.0%（2/50）vs 2.0%（1/50），χ²=1.197，P=1.000]。

经盆底超声检查发现二次自然分娩对女性盆底近期影响较初产自然分娩明显，同时盆底超声检查可为盆底障碍性疾病筛查和诊断提供可靠依据。

To observe the near-term impact of the second natural delivery on the structure of a female pelvic floor by ultrasonography.

Selected fifty second-natural-delivery women and fifty first-natural-delivery women from Tongde Hospital of Zhejiang Province between October, 2016 and October, 2017 undertook pelvic ultrasonnography (42 days postpartum). Pelvic ultrasonography was used to determine all mothers′ bladder neck descent, bladder posterior angle, bladder neck tilt angle, bladder neck rotation angle, and the area of pelvic diaphragm hiatus when performing the Valsalva maneuver. Besides, pelvic ultrasonography was used to determine the extent of mothers′ internal-urethral-of-orifice funneling, perineal hyperactivity, uterine prolapse and rectal bulge. The paired t test was applied between groups to compare the bladder neck descent, bladder posterior angle, bladder neck tilt angle, bladder neck rotation angle and the area of pelvic diaphragm hiatus of the second-natural-delivery mothers with those of the first-natural-delivery mothers. The χ² test was also applied to examine the degree of mothers′ uterine prolapse, rectal bulge and internal-urethral-of-orifice funneling, as well as their perineal hyperactivity rate.

The bladder neck descent, bladder posterior angle, bladder neck tilt angle, bladder neck rotation angle and the area of pelvic diaphragm hiatus of the second-natural-delivery mothers were all wider than those of the first-natural-delivery mothers [(29.37±5.32) mm vs (22.63±6.35) mm, (148.8±14.97)^° vs (141.2±15.20)^°, (73.69±16.03)^° vs (69.8±15.25)^°, (44.41±19.27)^° vs (40.0±17.52)^°, (21.47±5.19) cm² vs (19.15±4.10) cm²], and differences were statistically significant (t=5.761, P<0.001; t=2.519, P=0.001; t=2.476, P=0.001; t=3.123, P=0.001; t=2.481, P<0.001). The degree of the second-natural-delivery mothers′ uterine prolapse and internal-urethral-of-orifice funneling as well as their perineal hyperactivity rate were all higher than those of the first-natural-delivery mothers [46.0% (23/50) vs 20.0% (10/50), 12.0% (6/50) vs 6.0% (3/50), 20.0% (10/50) vs 6.0% (3/50)], and differences were statistically significant (χ²=7.644, P=0.006; χ²=3.342, P=0.043; χ²=4.332, P=0.037). The differences in the incidence rate of rectal bulge between the two groups were of no statistical significance [4.0% (2/50) vs 2.0% (1/50), χ²=1.197, P=1.000].

The pelvic ultrasonogram showed that the near-term impacts of the second natural-delivery on women′s pelvic floor were more obvious than those of the first natural delivery. What′s more, pelvic floor ultrasound has been proved to be a reliable basis for the diagnosis and screening of dysfunctional diseases of pelvic floor.