目的：探讨不同分娩方式巨大儿对初产妇盆膈裂孔形态学的近期影响。方法：将4０例单胎初产妇先根据新生儿体质量分为正常儿组（２ ５００～３ ９９９ ｇ）20例和巨大儿组（≥４ ０００ ｇ）20例，再根据分娩方式将产后正常儿组分为顺产组10例和剖宫产组10例，产后巨大儿组分为顺产组10例和剖宫产组10例。经会阴三维超声技术检查，获取盆膈裂孔声像图，观察静息、缩肛动作和Valsalva动作时盆膈裂孔的形态，并测量相关参数。结果：无论静息期、缩肛期和张力期盆膈裂孔的前后径、左右径、面积及周长产后巨大儿顺产组都大于巨大儿剖宫产组、正常儿顺产组及正常儿剖宫产组各组径线，差异有统计学意义（P<0.05），巨大儿剖宫产组在缩肛期盆膈裂孔的前后径、左右径、面积、周长及张力期的面积均大于正常儿剖宫产组，差异有统计学意义（P<0.05），巨大儿剖宫产组在张力期的左右径、周长均大于正常儿顺产组及正常儿剖宫产组，差异有统计学意义（P<0.05）。结论：不同分娩方式对初产妇盆膈裂孔的影响不同。妊娠和顺产分娩巨大儿对产妇盆膈裂孔形态与大小的影响更大。剖宫产较顺产对初产妇盆膈裂孔近期损伤有所减轻。

Objective: To investigate the short-term effects of different fetal macrosomia delivery methods on the morphology of the pelvic diaphragm hiatus in the primiparas. Methods: A total of 40 primiparous women were divided into postnatal normal newborn group(2 500~3 999 g, 20 cases) and postnatal fetal macrosomia group(≥4 000 g, 20 cases). Further, the whole 40 primiparas were grouped in the light of delivery way: postnatal normal newborn vaginal delivery group(10 cases) and caesarean group(10 cases), postnatal fetal macrosomia vaginal delivery group(10 cases) and postnatal fetal macrosomia caesarean group(10 cases). Perineal three-dimensional ultrasound was performed to observe the morphology and measure the parameters of pelvic hiatus at resting, pelvic muscle contraction and during maximum valsalva maneuver. Results: Regardless of the resting stage, anal stage and tension stage, the pelvic diaphragm hiatus anteroposterior diameter, left-right diameter, area and perimeter of the postnatal fetal macrosomia vaginal delivery group are greater than that of the postnatal fetal macrosomia caesarean group, postnatal normal newborn vaginal delivery group and postnatal normal caesarean group(P<0.05). The anteroposterior diameter, left-right diameter, area and perimeter in the anal stage and the area of postnatal fetal macrosomia caesarean group in the tension period are higher than postnatal normal caesarean group(P<0.05), with statistical significance. In the tension stage, the postnatal fetal macrosomia caesarean group diaphragm hiatus, left-right diameter, perimeter are greater than postnatal normal newborn vaginal delivery group and caesarean group(P<0.05), with statistical significance. Conclusion: Different ways of delivery have different influence on the primipara pelvic diaphragm pregnancy and childbirth are more likely to cause the change of the morphology and size of the pelvic diaphragm hiatus. Cesarean has less injury on pelvic diaphragm for first-time mothers than natural labor.