经阴道超声测量宫颈长度对初产妇足月引产的预测研究

Labor Induction Prediction among Nulliparous Using Transvaginal Ultrasonographic Measurement of Cervical Length

目的 探讨经阴道超声测量宫颈长度对预测初产妇足月引产及分娩方式的价值。 方法 对 12 1例需引产的足月单胎初产孕妇 ,于引产当日经阴道超声测量宫颈长度、宫颈管的宽度 ,记录宫颈内口有无开大和宫颈的位置 ,同时由专人用指检法进行 Bishop评分 ,记录引产潜伏期 ,产程及分娩方式 ,分析引产潜伏期和分娩方式的相关因素。 结果 多因素逐步回归分析和对数回归显示单一超声测量的宫颈长度是预测引产潜伏期 (r=0 .6 7,P<0 .0 0 1)和分娩方式 (r=0 .6 1,P<0 .0 0 1)的相关因素 ,Bishop评分虽和宫颈长度相关 (r=- 0 .6 8,P<0 .0 0 1) ,但和宫颈长度相比不是预测引产潜伏期和分娩方式的相关因素。超声测量的宫颈长度 <3cm时 ,平均引产潜伏期 (9± 7) h,剖宫产率 34.5 % ;宫颈长度≥ 3cm时引产潜伏期 (2 3± 7) h,剖宫产率 88.1%。二者比较差异有显著性 (P<0 .0 0 1)。 结论 对于初产妇而言 ,经阴道超声测量宫颈长度可以预测引产潜伏期和分娩方式 ,优于传统的 Bishop评分。经阴道测量宫颈长度可以用于评价初产妇引产前的宫颈成熟度。

Objectives To determine the predictive effect of the transvaginal ultrasonographic cervical measurement in induction of labor among the nulliparous. Methods This prospective observational study recruited women with singleton gestation scheduled for induction of labor at ≥37 weeks. All the pregnancy women were nulliparous. Transvaginal ultrasonographic cervical measurement was performed and Bishop score was detemined, each by operators masked to the other measurement. Data were collected on parity, gestational age, mode of delivery, induction agent, induction onset of labor interval, Bishop score and cervical measurement. Results A total 121 women were included. A stepwise regression model identified cervical length was the best linear predictor of induction to onset of labor interval. ( r=0.67, P <0.001). A logistic regression model found cervical length was the only independent predictor of mode of delivery. Bishop score was correlated with the cervical length ( r=-0.68,P <0.001), but comparing with the cervical length it was not the predicting factors. When cervical length ≥3 cm, the induction to onset of labor interval was (23±7)h and the cesarean section rate was 88.1%. When the cervical length<3 cm,the induction to onset of labor interval was (9±7)h and the cesarean rate was 34.5%. The difference was significant( P< 0.001 ). Conclusions The cervical length through transvaginal ultrasonographic measurement is the independent predictor of induction to onset of labor interval and the mode of delivery for the nulliparous and the Bishop score is not the predictor. It can reflect the maturity of the cervix before the induction of the term nulliparous.