This study aims to explore the applicability of an innovative cervical tactile ultrasound approach for predicting spontaneous preterm birth (sPTB). Eligible participants were women with low-risk singleton pregnancies in their second trimester, enrolled in this prospective observational study. A Cervix Monitor (CM) device was designed with a vaginal probe comprising four tactile sensors and a single ultrasound transducer operating at 5 MHz. The probe enabled the application of controllable pressure to the external cervical surface, facilitating the acquisition of stress-strain data from both anterior and posterior cervical sectors. These data were used to calculate cervical elasticity, as a stress-to-strain ratio. CM examination data were analyzed for 127 women at 24 - 28 gestational weeks. PTB was observed in 6.3% (8 out of 127) of the cases. The preterm group exhibited a lower average cervical stress-to-strain ratio (elasticity) of 0.70±0.26 kPa/mm compared to the term group's 1.63±0.65 kPa/mm, with a significant p-value of 1.1×10-4. Diagnostic accuracy for predicting spontaneous preterm birth based solely on cervical elasticity data was found to be 95.0% (95% CI, 88.5–100.0). These findings suggest that measuring cervical elasticity with the designed tactile ultrasound probe could potentially predict spontaneous preterm birth in a cost-effective manner.