The main causes of dystocia of vertex presentation were occiput malpresentation, macrosomic infant, uterine atony, abnormal pelvic and genital tract.

导致头位难要因素依次为胎头位置异常、巨大儿、宫缩力、软道及骨道异常。

Objective:To survey the normal values of pelvic inclination of external pelvimetry and to provide evidence so as to estimate dystocia risk index for antenatal care.

骨盆倾斜度正常值,为前检查估计难风险指数提供依据。