Amniocentesis before cerclage in asymptomatic women with mid-trimester short cervix: time to consider?

The efficacy of cervical cerclage (CC) in cases of asymptomatic mid-trimester short cervix, or the ultrasound finding of a cervical length<25 mm within 24 weeks of gestation, has been documented in women with a previous history of preterm birth (PTB). Conversely, no robust evidence supports the role of cervical cerclage in prolonging pregnancy and improving maternal-neonatal outcomes in pregnant patients with mid-trimester short cervix detected by sonography and no prior history of PTB. However, the limited effect of CC in this population may be partially explained by the lack of preprocedure diagnosis of underlying intra-amniotic inflammation/infection that could undermine the beneficial effect of mechanical continence exerted by cervical cerclage. Performing an amniocentesis in cases of mid-trimester short cervix and analyzing the amniotic fluid for inflammatory markers, including IL-6 and MMP-8 and the presence of pathogens in the amniotic cavity by standard culture techniques, digital polymerase chain reaction, or, more recently, third-generation sequencing techniques may offer the opportunity for a differential diagnosis between mechanical and inflammatory cervical insufficiency. In this review, we explore the available literature on intra-amniotic inflammation/infection in mid-trimester short cervix and discuss the potential role of analyzing amniotic fluid by amniocentesis before cervical cerclage to improve the selection of patients who may benefit from cerclage or alternative management strategies, including antibiotics in selected cases of intra-amniotic inflammation/infection. An individualized approach to maternal-fetal care in this context may represent a promising strategy for addressing cervical insufficiency and potentially improving the efficacy of therapeutic options to prevent PTB. VIDEO ABSTRACT.