病史指征宫颈环扎术后宫颈长度变化与<34周早产的研究

Cervical length changes in singleton pregnancies following history-indicated cerclage and their impact on preterm birth <34 weeks of gestation

目的探讨在病史指征的宫颈环扎术人群中超声监测宫颈长度(cervical length,CL)的变化及环扎术后<24周短宫颈(CL≤2.5 cm)对<34周早产的预测价值。方法回顾性收集2010年1月至2021年6月在北京大学第一医院行病史指征McDonald宫颈环扎术且资料完整的单胎孕妇共145例的临床资料,记录在围手术期及环扎术后孕≥20~24、≥24~28、≥28~32周经阴道超声测量的闭合段CL,按分娩孕周分为≥34周分娩组(n=118)和<34周分娩组(n=27),分析2组环扎术后CL与<34周早产的关系及环扎术后孕≥20~24周短宫颈孕妇早产的风险。采用χ2检验或独立样本t检验进行组间比较,采用多因素logistic回归分析2组的CL与<34周早产的关系,并利用受试者工作特征曲线分析环扎术后CL对妊娠结局的预测价值。结果(1)在145例病例中,足月分娩106例(73.1%),<34周早产27例(18.6%),其中7例(4.8%)<28周分娩(晚期流产)(其中2例为有生机儿并存活),总体活产率96.6%(140/145)。(2)≥34周分娩组孕妇CL在≥20~24、≥24~28、≥28~32周均显著长于<34周分娩组[(3.35±0.73)与(2.39±1.03)cm,t=5.69,P=0.008;(3.14±0.75)与(2.14±1.10)cm,t=5.65,P=0.007;(2.91±0.85)与(1.79±1.09)cm,t=5.84,P=0.005]。(3)多因素logistic回归分析显示,环扎术后孕≥20~24、≥24~28、≥28~32周CL是发生<34周早产的影响因素[OR值(95%CI)分别为0.885(0.837~0.935)、0.886(0.837~0.937)、0.890(0.842~0.940),P值均<0.001]。(4)受试者工作特征曲线结果显示,孕≥20~24、≥24~28和≥28~32周的CL对预测<34周早产的曲线下面积分别为0.747、0.734、0.799,灵敏度分别为60.0%、60.0%、80.0%,特异度分别为87.5%、91.3%、76.9%。(5)宫颈环扎术后孕≥20~24周短宫颈发生率为17.2%(25/145),其发生<34周早产的风险为CL>2.5 cm孕妇的12.7倍(OR=12.7,95%CI:4.58~35.40,P<0.001)。结论病史指征行宫颈环扎术的孕妇中,术后孕≥20~24、≥24~28、≥28~32周的CL对妊娠结局具有一定的预测价值;环扎术后孕≥20~24周短宫颈对预测<34周早产有意义。

Objective To investigate the changes in cervical length(CL)after history-indicated cerclage through serial ultrasound measurements and the predictive value of short cervix(CL≤2.5 cm)before 24 gestational weeks after cerclage in preterm delivery before 34 weeks.Methods In this retrospective study,clinical data of 145 singleton pregnancies with history-indicated McDonald cerclage at Peking University First Hospital from January 2010 to June 2021 were collected.CL was measured through transvaginal ultrasound and recorded during the perioperative period and at≥20-24,≥24-28,and≥28-32 weeks of gestation.The participants were divided into≥34 weeks group(n=118)and<34 weeks group(n=27)based on the gestational age at delivery.Chi-square or independent sample t test was applied for comparison between the two groups.The relationship between CL after cerclage and preterm birth before 34 week in the two groups was analyzed using multivariate logistic regression analysis.The risk of preterm birth in women with short cervix at 20-24 weeks of gestation after cerclage was estimated.The receiver operator characteristic curve was adopted for predicting the diagnostic value of postoperative CL on pregnancy outcomes.Results(1)Among the 145 cases,106 cases(73.1%)had term delivery,27 cases(18.6%)had premature delivery before 34 weeks,among which seven cases(4.8%)had late miscarriage before 28 weeks(including two cases with survived viable infants).The overall live birth rate was 96.6%(140/145).(2)In the≥34 weeks group,CL at≥20-24,≥24-28,and≥28-32 weeks of gestation were significantly longer than those in the<34 weeks group[(3.35±0.73)vs(2.39±1.03)cm,t=5.69,P=0.008;(3.14±0.75)vs(2.14±1.10)cm,t=5.65,P=0.007;(2.91±0.85)vs(1.79±1.09)cm,t=5.84,P=0.005].(3)Multivariate logistic regression analysis showed that CL at≥20-24,≥24-28,and≥28-32 weeks after cerclage were the influencing factors of preterm birth before 34 weeks[OR(95%CI)=0.885(0.837-0.935),0.886(0.837-0.937),0.890(0.842-0.940),respectively,all P<0.001].(4)The area under the curve of CL at≥20-24,≥24-28,and≥28-32 weeks were 0.747,0.734,and 0.799 for predicting delivery before 34 weeks,with the sensitivity of 60.0%,60.0%,and 80.0%,and the specificity of 87.5%,91.3%,and 76.9%,respectively.(5)At≥20-24 weeks after cervical cerclage,women with a short cervix accounted for 17.2%(25/145),who were 12.7 times more likely to have premature birth before 34 weeks than those with a CL over 2.5 cm(OR=12.7,95%CI:4.58-35.40,P<0.001).Conclusions Among pregnant women with history-indicated cervical cerclage,CL after cerclage at≥20-24,≥24-28,and≥28-32 weeks of gestation have predictive values for pregnancy outcomes.A short cervix at≥20-24 weeks of pregnancy after cerclage could predict premature birth before 34 weeks.