Cervical length screening for prevention of preterm birth in singleton pregnancy with threatened preterm labor: systematic review and meta‐analysis of randomized controlled trials using individual patient‐level data

OBJECTIVE: Cervical length screening by transvaginal sonography (TVS) has been shown to be a good predictive test for spontaneous preterm birth (PTB) in symptomatic singleton pregnancy with threatened preterm labor (PTL). The aim of this review and meta-analysis of individual participant data was to evaluate the effect of knowledge of the TVS cervical length (CL) in preventing PTB in singleton pregnancies presenting with threatened PTL. METHODS: We searched the Cochrane Pregnancy and Childbirth Group's Trials Register and the Cochrane Complementary Medicine Field's Trials Register (May 2016) and reference lists of retrieved studies. Selection criteria included randomized controlled trials of singleton gestations with threatened PTL randomized to management based mainly on CL screening (intervention group), or CL screening with no knowledge of results or no CL screening (control group). Participants included women with singleton gestations at 23 + 0 to 36 + 6 weeks with threatened PTL. We contacted corresponding authors of included trials to request access to the data and perform a meta-analysis of individual participant data. Data provided by the investigators were merged into a master database constructed specifically for the review. The primary outcome was PTB < 37 weeks. Summary measures were reported as relative risk (RR) or as mean difference (MD) with 95% CI. RESULTS: Three trials including a total of 287 singleton gestations with threatened PTL between 24 + 0 and 35 + 6 weeks were included in the meta-analysis, of which 145 were randomized to CL screening with knowledge of results and 142 to no knowledge of CL. Compared with the control group, women who were randomized to the known CL group had a significantly lower rate of PTB < 37 weeks (22.1% vs 34.5%; RR, 0.64 (95% CI, 0.44-0.94); three trials; 287 participants) and a later gestational age at delivery (MD, 0.64 (95% CI, 0.03-1.25) weeks; MD, 4.48 (95% CI, 1.18-8.98) days; three trials; 287 participants). All other outcomes for which there were available data were similar in the two groups. CONCLUSIONS: There is a significant association between knowledge of TVS CL and lower incidence of PTB and later gestational age at delivery in symptomatic singleton gestations with threatened PTL. Given that in the meta-analysis we found a significant 36% reduction in the primary outcome, but other outcomes were mostly statistically similar, further study needs to be undertaken to understand better whether the predictive characteristics of CL screening by TVS can be translated into better clinical management and therefore better outcomes and under what circumstances. Copyright © 2016 ISUOG. Published by John Wiley RR 0,64 (IC 95%, 0,44-0,94); 3 ensayos; 287 participantes ) y una edad gestacional al momento del parto más tardía (DM 0,64 (IC 95%, 0.03-1.25) semanas; DM 4,48 (IC 95%, 1,18-8,98) días; 3 ensayos; 287 participantes). El resto de los resultados para los cuales había datos disponibles fueron similares en ambos grupos. CONCLUSIONES: Existe una asociación significativa entre el conocimiento de la LC obtenida mediante ETV y una menor incidencia de PPTE y edad gestacional más tardía en el momento del parto en embarazos con feto único sintomáticos debido al riesgo de parto pretérmino (PPT). Teniendo en cuenta que en el metaanálisis se encontró una reducción significativa del 36% en el resultado primario, pero que los otros resultados fueron estadísticamente similares en su mayoría, serán necesarios más estudios para entender mejor si las propiedades predictivas del cribado mediante la LC obtenida con ETV se pueden traducir en una mejor atención clínica y por lo tanto mejores resultados dependiendo de las circunstancias. :META: : ,(preterm labor,PTL),(transvaginal sonography,TVS)(spontaneous preterm birth,PTB)。metaPTL,TVS(cervical length,CL)PTB。 : CochraneCochrane(20165)。PTL,CL()CLCL()。23 + 036+6PTL。,,meta。。37PTB。(relative risk,RR)95%CI(mean difference,MD)。 : meta3,28724 + 035+6PTL,145CL,142CL。,CL37PTB22.1%34.5%;RR,0.64(95% CI,0.44 ~ 0.94);3;287,MD,0.64(95% CI,0.03 ~ 1.25);MD,4.48(95% CI,1.18 ~ 8.98);3;287。2,。 : PTL,TVS CLPTB。meta36%,,,TVSCL,。.