Abnormalities of the powers uterine inertia 1.Etiology of uterine inertia Cephalopelvic disproportion or Fetal malposition Abnormal of uterine muscle Imbalance of endocrine system Administration of analgesia psychical-factors Others fatigue RENJI HOSPITAL6 RENJI HOSPITAL Abnormalities of the powers -----uterine inertia 1.Etiology of uterine inertia uCephalopelvic disproportion or Fetal malposition uAbnormal of uterine muscle uImbalance of endocrine system uAdministration of analgesia upsychical-factors uOthers fatigue