Department of Obstetrics and Gynecology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea (Hong, Kang, Park, Ko).
Department of Obstetrics and Gynecology, Incheon St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Incheon, Republic of Korea (Lee).
Am J Obstet Gynecol MFM. 2024 Oct;6(10):101476. doi: 10.1016/j.ajogmf.2024.101476. Epub 2024 Aug 30.
Short cervical length in the mid-trimester is a powerful predictor of preterm birth (PTB). However, clinical significance of cervical length in the third trimester for predicting PTB has not been established yet.
To examine the predictive role of a shortened cervix in the third trimester for PTB in women who had a normal cervical length in the second trimester STUDY DESIGN: This retrospective cohort study included women who underwent cervical length measured at least once in both the second trimester (16+0 weeks to 27+6weeks) and the early third trimester (28+0 weeks to 33+6 weeks). Women with short cervical length in the second trimester, those with multiple pregnancies, those who underwent cerclage operation, and those who had iatrogenic PTB were excluded. The study population was divided into two groups based on cervical length in the third trimester: a short cervix (≤25 mm) group and a control group (>25 mm). Rates of PTB (<37 weeks) were compared between two groups. Predictive performances of cervical length in the third trimester for PTB were assessed.
Women with a short cervical length at 28+0 to 33+6 weeks accounted for 12.6% (n=717) of the total study population (n=5682). PTB rate was 9.5% in the short cervix group, which was significantly higher than that (3.2%) in the control group (P<.001). The adjusted odds ratio for short cervical length on PTB was 2.73 (95% CI: 1.96-3.79). A short cervix in the third trimester had a sensitivity of 30.1%, a specificity of 88.1%, a positive predictive value of 9.5%, and a negative predictive value (NPV) of 96.8% in predicting PTB. The addition of third-trimester cervical length to the predictive model significantly increased the area under the curve from 0.64 (95% CI: 0.60-0.68) to 0.67 (95% CI: 0.63-0.71) (P=.002), demonstrating improved predictive performance.
Approximately 13% of women with normal cervical length in the mid-trimester had a short cervical length after 28 weeks, which increased the risk of PTB. The high specificity and NPV of third-trimester cervical length measurements underscore their critical utility in identifying women at low risk for preterm delivery.
中期妊娠时的短宫颈长度是早产（PTB）的有力预测指标。然而，尚未确定第三孕期宫颈长度预测 PTB 的临床意义。
检查第三孕期宫颈缩短对中期妊娠时宫颈长度正常的女性发生 PTB 的预测作用。
这项回顾性队列研究纳入了至少在第二孕期（16+0 周至 27+6 周）和早第三孕期（28+0 周至 33+6 周）进行过宫颈长度测量的女性。排除了第二孕期宫颈长度缩短、多胎妊娠、行宫颈环扎术以及医源性 PTB 的女性。根据第三孕期的宫颈长度将研究人群分为两组：短宫颈（≤25mm）组和对照组（>25mm）。比较两组的 PTB（<37 周）发生率。评估第三孕期宫颈长度对 PTB 的预测性能。
在 28+0 至 33+6 周时宫颈长度缩短的女性占总研究人群（n=5682）的 12.6%（n=717）。短宫颈组的 PTB 发生率为 9.5%，明显高于对照组（3.2%）（P<.001）。第三孕期宫颈长度短与 PTB 的调整比值比为 2.73（95%CI：1.96-3.79）。第三孕期宫颈长度短预测 PTB 的灵敏度为 30.1%，特异性为 88.1%，阳性预测值为 9.5%，阴性预测值（NPV）为 96.8%。将第三孕期宫颈长度纳入预测模型显著提高了曲线下面积，从 0.64（95%CI：0.60-0.68）增加到 0.67（95%CI：0.63-0.71）（P=.002），表明预测性能得到改善。
约 13%的中期妊娠宫颈长度正常的女性在 28 周后宫颈长度缩短，增加了早产的风险。第三孕期宫颈长度测量的高特异性和 NPV 突出了其在识别低早产风险女性方面的关键作用。
