Cerclage After Full Dilatation Caesarean Section

CRAFT-OBS: Observational Study; To evaluate subsequent pregnancy risk of preterm birth in women with a history of previous caesarean in established labour. This prospective study using clinically acquired cervical length and quantitative fetal fibronectin data will help establish a predictive model of preterm birth \<34 weeks and \<37 weeks. CRAFT-RCT: Randomised controlled trial arm; To assess treatment for short cervix in women at high risk of preterm birth following a caesarean section at full dilatation CRAFT-IMG: Imaging sub-study; To aid understanding of micro and macrostructural features within the cervix which predisposes to preterm birth in women with a previous full dilatation caesarean section. This will use MRI and an advanced transvaginal ultrasound protocol and to assess if structural changes can be visualised in the cervix.