Pessary Plus Progesterone to Prevent Preterm Birth in Women With Short Cervixes: A Randomized Controlled Trial

OBJECTIVE: To test the effectiveness of cervical pessary in addition to vaginal progesterone for the prevention of preterm birth in women with midpregnancy short cervixes. METHODS: We performed a multicenter, open-label, randomized controlled trial in 17 perinatal centers. Asymptomatic women with singleton or twin pregnancies and cervical lengths of 30 mm or less, measured at 18 0/7-22 6/7 weeks of gestation, were randomized to cervical pessary plus vaginal progesterone (pessary plus progesterone group) or vaginal progesterone only (progesterone-only group) (200 mg/day). Treatments were used from randomization to 36 weeks of gestation or delivery. The primary outcome was a composite of neonatal mortality and morbidity. Secondary outcomes were delivery before 37 weeks and before 34 weeks of gestation. Analysis was performed according to intention to treat. RESULTS: Between July 9, 2015, and March 29, 2019, 8,168 women were screened, of whom 475 were randomized to pessary and 461 to progesterone only. The composite perinatal outcome occurred in 19.2% (89/463) of the women in the pessary group compared with 20.9% (91/436) of the women in the progesterone-only group (adjusted risk ratio [aRR] 0.88, 95% CI 0.69-1.12). Delivery rates before 37 weeks of gestation were 29.1% compared with 31.4% (aRR 0.86, 95% CI 0.72-1.04); delivery rates before 34 weeks were 9.9% compared with 13.9% (aRR 0.66, 95% CI 0.47-0.93). Women in the pessary group had more vaginal discharge (51.6% [245/476] vs 25.4% [117/479] [P<.001]), pain (33.1% [157/476] vs 24.1% [111/479] [P=.002]), and vaginal bleeding (9.7% [46/476] vs 4.8% [22/479] [P=.004]). CONCLUSION: In asymptomatic women with short cervixes, the combination of pessary and progesterone did not decrease rates of neonatal morbidity or mortality when compared with progesterone only. CLINICAL TRIAL REGISTRATION: Brazilian Clinical Trial Registry (ReBec), UTN:U1111-1164-2636.