Center for Women's Reproductive Health, Department of Obstetrics and Gynecology, The University of Alabama at Birmingham, Birmingham, AL, USA.
Department of Obstetrics and Gynecology, College of Medicine, Health Sciences Center, University of Oklahoma, Oklahoma City, OK, USA.
J Matern Fetal Neonatal Med. 2022 Dec;35(25):9978-9982. doi: 10.1080/14767058.2022.2081499. Epub 2022 May 31.
To identify if there is an increased risk for spontaneous preterm birth (sPTB) across the continuum of measured, normal cervical lengths (CL) in low-risk women.
Retrospective cohort study of women with singleton pregnancies and no history of prior sPTB. Women were included if they underwent mid-trimester transvaginal CL measurement between February 2016 and August 2018 and had a measured, normal CL ≥25mm. Women were excluded for progesterone exposure, fetal anomalies, or an unmeasurable CL due to a poorly developed lower uterine segment. The primary study outcome was sPTB <37 weeks. Secondary outcomes included: sPTB <35 weeks, birth gestational age (GA), and the number of hospital evaluations for suspected preterm labor (PTL). Cervical length was considered in interval groups 25-29mm, 30-34mm, 35-39mm, 40-44mm, and ≥45mm. Outcomes were analyzed with χ test of trend and as a continuum (linear models, logistic regression and ROC curve), where appropriate.
985 women were included. The incidence of sPTB <37 weeks was 3.7%, with a mean birth GA of 38.7 ± 2.4 weeks. The odds of sPTB <37 weeks decreased with increasing cervical length, considered in 5 mm intervals (odds ratio = 0.67; 95% confidence interval 0.49-0.90) and an increasing birth GA of 1 additional day for each CL increase of 3mm ( = .0002). Conversely, sPTB <35 weeks ( = .49) and mean hospital evaluations for PTL ( = .26) were similar across groups. The ROC curve area-under-the-curve for sPTB <37 weeks of 0.64 showed poor predictive value.
Among women without a history of sPTB, there was an association of decreased risk of sPTB <37 weeks and advanced delivery GA with increasing, but normal-range CL measurements. However, the association was poor and was not associated with spontaneous preterm birth <35 weeks, or the number of hospital evaluations for PTL.
在低危人群中，确定在测量的正常宫颈长度（CL）范围内，是否存在自发早产（sPTB）风险增加的情况。
这是一项回顾性队列研究，纳入了单胎妊娠且无既往 sPTB 史的女性。如果她们在 2016 年 2 月至 2018 年 8 月期间接受了经阴道中孕期 CL 测量，且测量的正常 CL≥25mm，则纳入研究。排除有孕激素暴露、胎儿异常或因下段子宫发育不良而无法测量 CL 的患者。主要研究结局为 sPTB<37 周。次要结局包括：sPTB<35 周、出生孕龄（GA）和疑似早产（PTL）的住院评估次数。CL 长度以间隔 25-29mm、30-34mm、35-39mm、40-44mm 和≥45mm 分组进行分析。采用 χ²趋势检验和连续变量（线性模型、逻辑回归和 ROC 曲线）进行分析。
共纳入 985 名女性。sPTB<37 周的发生率为 3.7%，平均出生 GA 为 38.7±2.4 周。随着 CL 长度的增加（以 5mm 为间隔），sPTB<37 周的发生几率逐渐降低（比值比=0.67；95%置信区间 0.49-0.90），每增加 3mm CL，出生 GA 增加 1 天（ = .0002）。相反，sPTB<35 周（ = .49）和疑似 PTL 的平均住院评估次数（ = .26）在各组间无显著差异。sPTB<37 周的 ROC 曲线下面积为 0.64，提示预测价值较差。
在无 sPTB 史的女性中，随着正常范围内 CL 测量值的增加，sPTB<37 周和早产 GA 提前的风险降低，但相关性较差，且与 sPTB<35 周或疑似 PTL 的住院评估次数无关。
