Department of Obstetrics, Hospital das Clínicas, School of Medicine, University of São Paulo, São Paulo, Brazil.
J Perinat Med. 2010 Sep;38(5):479-84. doi: 10.1515/jpm.2010.088.
To compare cervical length (CL) at 18-21 and 22-25 weeks' gestation in twin pregnancies in prediction of spontaneous preterm delivery and to examine cervical shortening.
Retrospective cohort study of CL measured at 18-21 and 22-25 weeks' gestation in twin pregnancies.
Receiver operating characteristics (ROC) curve revealed area of 0.64 (95% CI 0.53-0.75) and 0.80 (95% CI 0.72-0.88) for measurements at 18-21 and 22-25 weeks, respectively (P<or=0.001). Sensitivities of 33.3% and 23% and negative predicting value (NPV) of 97.3% and 86.8% for delivery at <28 and <34 weeks gestation were reached for measurements at 18-21 weeks. Sensitivities of 71.4% and 38.2% and NPV of 99.1% and 91.4% for delivery at <28 and <34 weeks' gestation were reached for measurements at 22-25 weeks. Cervical length shortening analysis showed an area under ROC curve of 0.81 (95% CI 0.73-0.89) and best cut-off was at >or=2 mm/week. Sensitivities of 80% and 60.8% and NPV of 98.9% and 90.6% for delivery at <28 and <34 weeks gestation were reached.
In twin gestations, assessment of CL at 22-25 weeks is better than assessment at 18-21 weeks to predict preterm delivery before 34 weeks. Cervical shortening at a rate of >or=2 mm/weeks between 18 and 25 weeks gestation was a good predictor of spontaneous preterm birth in this high-risk population.
比较双胎妊娠 18-21 周和 22-25 周时的宫颈长度（CL）在预测自发性早产中的作用，并探讨宫颈缩短情况。
回顾性队列研究分析了双胎妊娠中 18-21 周和 22-25 周时的 CL 测量值。
受试者工作特征（ROC）曲线显示，18-21 周和 22-25 周测量的曲线下面积分别为 0.64（95%CI 0.53-0.75）和 0.80（95%CI 0.72-0.88）（P<0.001）。18-21 周测量时，分娩<28 周和<34 周的敏感度分别为 33.3%和 23%，阴性预测值（NPV）分别为 97.3%和 86.8%。22-25 周测量时，分娩<28 周和<34 周的敏感度分别为 71.4%和 38.2%，NPV 分别为 99.1%和 91.4%。宫颈长度缩短分析的 ROC 曲线下面积为 0.81（95%CI 0.73-0.89），最佳截断值为>或=2mm/周。18-25 周时，分娩<28 周和<34 周的敏感度分别为 80%和 60.8%，NPV 分别为 98.9%和 90.6%。
在双胎妊娠中，22-25 周时评估 CL 比 18-21 周时更能预测 34 周前的早产。18-25 周时宫颈每周缩短>或=2mm 是该高危人群自发性早产的良好预测指标。
