背景:预防双胞胎早产(PTB)的最佳方法尚未完全确定。最近的证据表明,在超声检查宫颈长度短或体格检查宫颈扩张的双胎妊娠中,宫颈环扎术的放置可能与降低PTB的风险有关。然而,这些证据主要基于小型研究,因此质疑这些发现的稳健性。这项系统评价的目的是确定宫颈环扎术在预防双胎妊娠中的PTB和不良母婴结局中的作用。
结果:搜索的关键数据库和最后搜索日期:MEDLINE,Embase,和CINAHL于2023年4月20日进行了电子搜索。合格标准:纳入标准是观察性研究,评估双胎环扎术与未行环扎术的双胎妊娠的PTB风险,以及将双胎妊娠分配到环扎术以预防PTB或对照组的随机试验(例如,安慰剂或照常治疗)。主要结果是PTB<妊娠34周。次要结局是PTB<妊娠37、32、28、24周,出生时的胎龄,诊断和出生之间的间隔,早产胎膜破裂(pPROM),绒毛膜羊膜炎,围产期损失,和围产期发病率。还根据环扎术的适应症(宫颈长度短或宫颈扩张)进行了亚组分析。偏倚风险评估:使用修订的Cochrane偏倚风险工具评估纳入的随机对照试验(RCT)的偏倚风险。而采用纽卡斯尔-渥太华量表(NOS)的观察性研究。统计分析:暴露与未暴露女性中检测到每种分类结果的可能性的汇总风险比(RR),和(b)暴露和未暴露妇女之间的汇总平均差异(MD)(对于每个连续结果),使用头对头荟萃分析计算其95%置信区间(CI).结果综合:包括18项研究(1,465个双胎妊娠)。双胎妊娠合并短宫颈的女性在超声检查或体检时宫颈扩张的宫颈环扎术与PTB<34孕周的风险降低相关(RR:0.73,95%CI[0.59,0.91],p=0.005,对应于绝对风险的16%差异,AR),<32(RR:0.69,95%CI[0.57,0.84],p<0.001;AR:16.92%),<28(RR:0.54,95%[CI0.43,0.67],0.001;AR:18.29%),和<24(RR:0.48,95%CI[0.23,0.97],p=0.04;AR:15.57%)妊娠周和出生时胎龄延长(MD:2.32周,95%[CI0.99,3.66],p<0.001)。宫颈长度短或宫颈扩张的双胎妊娠环扎术也与降低围产期丢失的风险相关(RR:0.38,95%CI[0.25,0.60],p<0.001;AR:19.62%)和复合不良结局(RR:0.69,95%CI[0.53,0.90],p=0.007;AR:11.75%)。宫颈长度<15mm的女性宫颈环扎与PTB<34周的风险降低相关(RR:0.74,95%CI[0.58,0.95],p=0.02;AR:29.17%)和宫颈扩张患者(RR:0.68,95%CI[0.57,0.80],p<0.001;AR:35.02%)。环扎和预防PTB与不良围产期结局之间的关联完全是由于纳入了观察性研究。在GRADE评估中检索到的证据质量较低。
结论:宫颈扩张或宫颈长度<15mm的急诊环扎术可能与PTB减少和改善围产期结局有关。然而,这些发现主要基于观察性研究,需要在大型且足够有效的RCT中进行确认.
The optimal approach to prevent preterm birth (PTB) in twins has not been fully established yet. Recent evidence suggests that placement of cervical cerclage in twin pregnancies with short cervical length at ultrasound or cervical dilatation at physical examination might be associated with a reduced risk of PTB. However, such evidence is based mainly on small studies thus questioning the robustness of these findings. The aim of this systematic
review was to determine the role of cervical cerclage in preventing PTB and adverse maternal or perinatal outcomes in twin pregnancies.
Key databases searched and date of last search: MEDLINE, Embase, and CINAHL were searched electronically on 20 April 2023. Eligibility criteria: Inclusion criteria were observational studies assessing the risk of PTB among twin pregnancies undergoing cerclage versus no cerclage and randomized trials in which twin pregnancies were allocated to cerclage for the prevention of PTB or to a control group (e.g., placebo or treatment as usual). The primary outcome was PTB <34 weeks of gestation. The secondary outcomes were PTB <37, 32, 28, 24 weeks of gestation, gestational age at birth, the interval between diagnosis and birth, preterm prelabor rupture of the membranes (pPROM), chorioamnionitis, perinatal loss, and perinatal morbidity. Subgroup analyses according to the indication for cerclage (short cervical length or cervical dilatation) were also performed. Risk of bias assessment: The risk of bias of the included randomized controlled trials (RCTs) was assessed using the Revised Cochrane risk-of-bias tool for randomized trials, while that of the observational studies using the Newcastle-Ottawa scale (NOS). Statistical analysis: Summary risk ratios (RRs) of the likelihood of detecting each categorical outcome in exposed versus unexposed women, and (b) summary mean differences (MDs) between exposed and unexposed women (for each continuous outcome), with their 95% confidence intervals (CIs) were computed using head-to-head meta-analyses. Synthesis of the results: Eighteen studies (1,465 twin pregnancies) were included. Placement of cervical cerclage in women with a twin pregnancy with a short cervix at ultrasound or cervical dilatation at physical examination was associated with a reduced risk of PTB <34 weeks of gestation (RR: 0.73, 95% CI [0.59, 0.91], p = 0.005 corresponding to a 16% difference in the absolute risk, AR), <32 (RR: 0.69, 95% CI [0.57, 0.84], p < 0.001; AR: 16.92%), <28 (RR: 0.54, 95% [CI 0.43, 0.67], 0.001; AR: 18.29%), and <24 (RR: 0.48, 95% CI [0.23, 0.97], p = 0.04; AR: 15.57%) weeks of gestation and a prolonged gestational age at birth (MD: 2.32 weeks, 95% [CI 0.99, 3.66], p < 0.001). Cerclage in twin pregnancy with short cervical length or cervical dilatation was also associated with a reduced risk of perinatal loss (RR: 0.38, 95% CI [0.25, 0.60], p < 0.001; AR: 19.62%) and composite adverse outcome (RR: 0.69, 95% CI [0.53, 0.90], p = 0.007; AR: 11.75%). Cervical cerclage was associated with a reduced risk of PTB <34 weeks both in women with cervical length <15 mm (RR: 0.74, 95% CI [0.58, 0.95], p = 0.02; AR: 29.17%) and in those with cervical dilatation (RR: 0.68, 95% CI [0.57, 0.80], p < 0.001; AR: 35.02%). The association between cerclage and prevention of PTB and adverse perinatal outcomes was exclusively due to the inclusion of observational studies. The quality of retrieved evidence at GRADE assessment was low.
Emergency cerclage for cervical dilation or short cervical length <15 mm may be potentially associated with a reduction in PTB and improved perinatal outcomes. However, these findings are mainly based upon observational studies and require confirmation in large and adequately powered RCTs.