目的　分析影响引产潜伏期的主要因素与评价引产成功的难易程度。方法　用会阴B超观察 10 5例初产妇宫颈的成熟状态 ,收集临床资料和引产潜伏期 (引产用药至临产的时间 ) ,作Cox模型分析。结果　宫颈长度、内口开张程度和先露高低是引产潜伏期的主要影响因素 ;会阴B超宫颈成熟度评分大于或等于 -4 5的孕妇更易在 12小时内临产。结论　宫颈的成熟状态是影响引产潜伏期的主要因素 ,会阴B超宫颈成熟度评分可用于估计引产难易程度 Objective To analyze the main factors influencing the latency of induction of labor and evaluate the difficulty of successful induction of labor. Methods Perineal B-ultrasound was used to observe the mature state of 105 cases of primiparous cervix. The clinical data and the latent period of induction of labor (the time from induction of labor to labor) were collected and analyzed by Cox model. Results The length of cervix, the degree of internal opening and the level of exposure were the main factors influencing the latent period of induction. Pregnant women with perineum B cervical maturity score greater than or equal to -4 5 were more likely to give birth within 12 hours. Conclusion Cervical maturation is the main factor affecting the latent period of induction of labor. The score of cervical perineal B-cervical maturity can be used to estimate the ease of induction of labor