Helen Schneider Hospital for Women, Rabin Medical Center, Petach Tikva, and Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel.
Am J Obstet Gynecol. 2014 Nov;211(5):532.e1-9. doi: 10.1016/j.ajog.2014.06.002. Epub 2014 Jun 4.
To determine whether the predictive accuracy of sonographic cervical length (CL) for preterm delivery (PTD) in women with threatened preterm labor (PTL) is related to gestational age (GA) at presentation.
A retrospective cohort study of all women with singleton pregnancies who presented with PTL at less than 34 + 0 weeks and underwent sonographic measurement of CL in a tertiary medical center between 2007 and 2012. The predictive accuracy of CL for PTD was stratified by GA at presentation.
Overall, 1077 women who presented with PTL have had sonographic measurement of CL and met the study inclusion criteria. Of those, 223 (20.7%) presented at 24 + 0-26 + 6 weeks (group 1), 274 (25.4%) at 27 + 0-29 + 6 weeks (group 2), 283 (26.3%) at 30 + 0-31 + 6 weeks (group 3), and 297 (27.6%) at 32 + 0-33 + 6 weeks (group 4). The overall performance CL as a predictive test for PTD was similar in the 4 GA groups, as reflected by the similar degree of correlation between CL with the examination to delivery interval (r = 0.27, r = 0.26, r = 0.28, and r = 0.29, respectively, P = .8), the similar area under the receiver-operator characteristic curve (0.641-0.690, 0.631-0.698, 0.643-0.654, and 0.678-0.698, respectively, P = .7), and a similar decrease in the risk of PTD of 5-10% for each additional millimeter of CL. The optimal cutoff of CL, however, was affected by GA at presentation, so that a higher cutoff of CL was needed to achieve a target negative predictive value for delivery within 14 days from presentation for women who presented later in pregnancy. The optimal thresholds to maximize the negative predictive value for delivery within 14 days were 36 mm, 32.5 mm, 24 mm and 20.5 mm for women who presented at 32 + 0 to 33 + 6 weeks, 30 + 0 to 31 + 6 weeks, 27 + 0 to 29 + 6 weeks and 24 + 0 to 26 + 6, respectively.
CL has modest predictive accuracy in women with threatened PTL, regardless of GA at presentation. However, the optimal cutoff of CL for the purpose of clinical decision making in women with PTL needs to be adjusted based on GA at presentation.
确定在有早产威胁的孕妇中，超声宫颈长度（CL）预测早产（PTD）的准确性是否与就诊时的孕龄（GA）有关。
这是一项对所有在 34+0 周前出现早产且在 2007 年至 2012 年间在三级医疗中心进行超声 CL 测量的单胎妊娠孕妇进行的回顾性队列研究。根据就诊时的 GA，对 CL 预测 PTD 的准确性进行分层。
共有 1077 名出现早产威胁的孕妇进行了超声 CL 测量并符合研究纳入标准。其中，223 名（20.7%）在 24+0-26+6 周（第 1 组），274 名（25.4%）在 27+0-29+6 周（第 2 组），283 名（26.3%）在 30+0-31+6 周（第 3 组），297 名（27.6%）在 32+0-33+6 周（第 4 组）。4 个 GA 组中，CL 作为 PTD 预测指标的整体性能相似，这反映在 CL 与检查至分娩间隔的相关性相似（r = 0.27、r = 0.26、r = 0.28 和 r = 0.29，P =.8），受试者工作特征曲线下面积相似（0.641-0.690、0.631-0.698、0.643-0.654 和 0.678-0.698，P =.7），每增加 1 毫米 CL，PTD 的风险降低 5-10%。然而，CL 的最佳截断值受到就诊时 GA 的影响，因此对于就诊时间较晚的孕妇，需要更高的 CL 截断值才能实现 14 天内分娩的阴性预测值目标。为了使 14 天内分娩的阴性预测值最大化，对于在 32+0 至 33+6 周、30+0 至 31+6 周、27+0 至 29+6 周和 24+0 至 26+6 周就诊的孕妇，最佳阈值分别为 36 毫米、32.5 毫米、24 毫米和 20.5 毫米。
在有早产威胁的孕妇中，CL 对预测早产有一定的准确性，无论就诊时的 GA 如何。然而，为了在 PTD 孕妇中进行临床决策，需要根据就诊时的 GA 调整 CL 的最佳截断值。
