Background: One of the most important causes of preterm birth (PTB) is cervical insufficiency, which usually it’s treated by performing a surgical cervical cerclage (CC). Currently, a valid alternative to surgical treatment is represented by the application of a non-invasive intravaginal silicon device called Arabin® pessary (AP). The aim of the study is to compare these two therapeutic approaches in terms of gestational and neonatal outcomes. Methods: In this observational cohort study, we retrospectively evaluated the pregnant women between 18 and 24 gestational weeks referred to the Department of Obstetrics and Gynecology of San Giovanni Calibita Fatebenefratelli Hospital of Rome from 2015 to 2017 with the diagnosis of threatened preterm birth. The 26 women were divided into groups according to the treatment received: cervical cerclage (Group-1, in-patient) and Arabin® pessary (Group-2, out-patient), both in combination with vaginal progesterone (PG). The primary outcome was the gestational age at delivery, and various secondary maternal and neonatal outcomes were considered. Results: The results do not show a statistically significant difference between the two groups, both in terms of gestational and neonatal outcomes. Considering surgical risks (anesthesia, blood loss), recovery-time and economic costs of CC, AP showed very interesting advantages resulting in more favorable cost-benefits relation. Conclusion: We confirmed once again that out-patient combination of AP and vaginal PG is a safe, non-invasive choice as treatment of PTB. Unfortunately, the small population doesn’t allow to define this a noninferiority trial. Further larger randomized controlled studies are needed to reassure clinicians about the efficacy of this combined non-invasive approach.