INTRODUCTION: We sought to assess if the evaluation of the cervical stroma before US-indicated cerclage placement contributes to the prediction of spontaneous preterm delivery (SPTD) <35 weeks. METHODS: Retrospective cohort study conducted at a single tertiary care institution. We collected information of women undergoing US-indicated cerclage from 2012 to 2017 who had transvaginal imaging of the cervix within 14 days before the procedure. We excluded cases of patients with other indications for cerclage, without cervical imaging before cerclage, Mullerian anomalies and multiple gestations. Measurement of the cervical length (CL) and stromal width of the posterior cervical lip were obtained. Our primary outcome was the rate of SPTD <35 weeks. Patients' consent and Institutional IRB approval were obtained. RESULTS: We analyzed outcomes of 110 patients who underwent US-indicated cerclage during the study period. The median gestational age at cerclage placement was 21 weeks. The median gestational age at delivery was 38 weeks. A total of 18/110 (19.8%) women delivered before 35 weeks. The median CL before cerclage for those who delivered <35 weeks was 13 mm compared to 17.4 mm for those delivering >35 weeks; P=0. 089. Meanwhile, the median cervical stroma in women delivering <35 weeks was 8.2 mm compared to 12.6 mm for those delivered >35 weeks; P=0.003 (after adjusting for confounders). CONCLUSION: Assessment of the cervical stroma is a useful predictor of SPTD <35 weeks in women who will undergo US-indicated cerclage. This technique is readily available and should be performed routinely in patients who will undergo US-indicated cerclage placement.