双胎孕妇子宫颈长度变化对自发性早产预测价值研究

Prediction of spontaneous preterm birth by cervical length changes in twin pregnancies

目的探讨孕中、晚期双胎孕妇子宫颈长度(CL)变化对自发性早产的预测价值。方法回顾性分析2014年1月至2017年12月在北京大学第三医院和北京市通州区妇幼保健院分娩的孕中期(20~25周)和孕晚期(28~32周)行阴道超声测量CL的双活胎孕妇166例资料,评估CL变化对32周前、34周前自发性早产的预测作用,使用bootstrap法比较ROC曲线下面积,评估孕晚期CL与单独孕中期CL预测32周前、34周前自发性早产的价值。结果 166例中足月分娩90例,早产分娩76例。全人群孕中、晚期CL中位数分别为34mm、29mm,足月分娩人群分别为35.5mm、31mm,早产分娩人群分别为32.5mm、21mm,3组人群比较差异均有统计学意义(均P<0.001)。按照CL缩短是否大于20%分为缩短组(CL缩短≥20%,78例)和稳定组(CL无缩短或缩短<20%,88例),缩短组较稳定组32周前、34周前早产率增加了2.22倍、1.85倍,但差异无统计学意义。CL≤25mm共计40例,其中34例在缩短组,6例在稳定组,排除这些双胎孕妇,缩短组较稳定组32周前、34周前早产率增加了7.58倍、2.09倍,缩短组与稳定组32周前早产率比较差异有统计学意义(P=0.049)。孕晚期CL较孕中期预测32周前、34周前早产ROC曲线下面积均增加,但差异均无统计学意义。结论在双胎孕妇中,孕28~32周CL缩短≥20%,其32周前的早产风险增加;当CL>25mm,CL缩短20%以上能更好地预测32周前早产。

Objective To investigate the predictive value of cervical length(CL)changes in spontaneous preterm birth(SPTB)in twin pregnancies in the second and third trimesters of pregnancy.Methods A retrospective analysis was made of 166 cases of twin pregnant women who underwent transvaginal ultrasound to measure CL during the second trimester of pregnancy(20~25 weeks)and the third trimester of pregnancy(28~32 weeks)from January 2014 to December 2017 in the Third Hospital of Peking University and Tongzhou Maternal and Child Health Hospital of Beijing.Evaluate the predictive value of CL changes in SPTB before 32 and 34 weeks.The area under the receiver-operating characteristics(ROC)curve was compared by bootstrap method.Assessment of the value of CL in the third trimester of pregnancy and CL in the second trimester of pregnancy alone in predicting SPTB before 32 and 34 weeks.Results Of the 166 cases,90 were full-term delivery and 76 were premature delivery.The median CL of mid and late pregnancy was 34 mm and 29 mm respectively,and it was 35.5 mm and 31 mm,and in full-term delivery.32.5 mm and21 mm in premature delivery,respectively.There were significant differences among the three groups(All P<0.001).According to whether the shortening of CL was more than 20%,they are divided into shortening group(CL shortening more than 20%,78 cases)and stabilizing group(no shortening of CL or shortening less than 20%,88 cases).The preterm birth rate of shortening group was 2.22 times and 1.85 times higher than that of stabilizing group before 32 weeks and 34 weeks,but there was no significant difference.Of 40 cases with CL≤ 25 mm,there were 34 cases in shortening group,6 cases in stabilizing group.Excluding these twin pregnant women,the preterm birth rate in the shortening group increased by 7.58 times and 2.09 times than that in the stabilizing group before 32 weeks and 34 weeks.There was a significant difference in the preterm birth rate between the shortening group and the stabilizing group before 32 weeks(P=0.049).The area under ROC curve of preterm birth predicted by CL in late pregnancy was increased compared with that in mid-pregnancy before 32 weeks and 34 weeks,but the difference was not statistically significant.Conclusion In twin pregnancies,the CL shortening ≥ 20% at 28~32 weeks of gestation increases the risk of preterm birth before 32 weeks;with CL>25 mm and CL shortening≥ 20%,it can better predict preterm birth before 32 weeks.