Department of Obstetrics and Gynecology, School of Medicine, University of Campinas, Campinas, SP, Brazil.
CISAM Maternity Hospital, University of Pernambuco, Recife, PE, Brazil.
Rev Bras Ginecol Obstet. 2023 Apr;45(4):171-178. doi: 10.1055/s-0043-1769467. Epub 2023 May 24.
To describe a reference curve for cervical length (CL) in mid-trimester twin gestations using transvaginal ultrasound (TVU) and to investigate whether short CL increases spontaneous preterm birth (sPTB) in asymptomatic twin pregnancies.
This was a prospective cohort study performed at 17 outpatient antenatal facilities of Brazil with women at 18 0/7 to 22 6/7 weeks of gestation who participated in a randomized clinical trial screening phase (P5 trial) between July 2015 and March 2019. TVU was performed to provide CL measurement in all screened women. Almost all women with CL ≤ 30 mm received vaginal progesterone 200mg/day and they were also randomized to receive cervical pessary or not. We considered data from the CL distribution among asymptomatic twin pregnancies and analyzed CL and its association with PTB generating receiver operating characteristics (ROC) curves and Kaplan-Meier curves.
A total of 253 pregnant women with twins were included in the distribution curve. The mean CL was 33.7 mm and median was 35.5mm. The 10th percentile was 17.8mm. We identified a PTB rate of 73.9% (187/253) with 33.6% of sPTB < 37 (85/253) and 15% (38/253) of sPTB < 34 weeks. The best cutoff point to predict sPTB < 37 was 24.15 mm. However, the ROC curve showed a poor performance (0.64). The Kaplan-Meier survival curves identified that only CL values ≤ 20mm were associated to sPTB < 34 weeks.
A cutoff point of CL ≤ 20 mm can be interesting point to identify short cervix in Brazilian twin pregnancies. However, in Brazilian asymptomatic twin pregnancies, CL does not show a good performance to predict PTB.
通过经阴道超声（TVU）描述中孕期双胎妊娠的宫颈长度（CL）参考曲线，并探讨CL 缩短是否会增加无症状双胎妊娠的自发性早产（sPTB）。
这是一项前瞻性队列研究，在巴西的 17 个门诊产前设施中进行，研究对象为 18 0/7 至 22 6/7 孕周的孕妇，她们参加了 2015 年 7 月至 2019 年 3 月期间的一项随机临床试验筛查阶段（P5 试验）。对所有筛查妇女进行 TVU 以提供 CL 测量。几乎所有 CL ≤ 30mm 的妇女均接受 200mg/天阴道孕酮治疗，且她们还随机接受宫颈托或不接受宫颈托。我们考虑了无症状双胎妊娠中 CL 分布的数据，并分析了 CL 及其与 PTB 的关系，生成了受试者工作特征（ROC）曲线和 Kaplan-Meier 曲线。
共有 253 名双胎妊娠孕妇纳入分布曲线。CL 的平均值为 33.7mm，中位数为 35.5mm。第 10 百分位数为 17.8mm。我们发现早产率为 73.9%（187/253），其中 33.6%的 sPTB <37 周（85/253），15%的 sPTB <34 周（38/253）。预测 sPTB <37 的最佳截断点为 24.15mm。然而，ROC 曲线显示性能不佳（0.64）。Kaplan-Meier 生存曲线表明，仅 CL 值≤20mm 与 sPTB <34 周有关。
在巴西的双胎妊娠中，CL ≤ 20mm 的截断点可能是识别短宫颈的有趣指标。然而，在巴西的无症状双胎妊娠中，CL 不能很好地预测 PTB。
