© 2015 John Wiley & Sons, Ltd. Objective: The aim of this study was to describe whether the prophylactic use of a cervical pessary decreases the rate of premature birth in congenital diaphragmatic hernia (CDH) fetuses treated with fetoscopic tracheal occlusion (FETO). Methods: The study concerns a consecutive series of cases with CDH and FETO and a group of CDH without FETO. In a subgroup of the FETO group, a prophylactic cervical pessary was inserted the day following the procedure. Gestational age (GA) at birth was the primary outcome. Results: Fifty-nine fetuses with FETO and 47 expectantly managed were included. The last 15 FETO had a cervical pessary inserted. The median GA at delivery in the FETO group with pessary was 35.1weeks and was not different from that in the FETO group without a pessary (34.3weeks; p=0.28) but was below that in the expectantly managed group (38.3weeks; p<0.001). Conclusion: Early results suggest that prophylactic use of an Arabin cervical pessary does not prolong gestation of CDH fetuses treated with FETO.