Cervical Pessary Versus Vaginal Progesterone in Singletons with a Short Cervix: a Randomized Controlled Trial

A short cervix is a risk factor for preterm birth (PTB). We aimed to compare the effectiveness of pessary and vaginal progesterone in women with a singleton pregnancy and a short cervix for the improvement of perinatal outcome through prevention of PTB. We performed an open-label, multi-center randomized clinical trial in 20 hospitals in the Netherlands. The trial was registered in the Dutch Trial register as NTR 4414. Women with a singleton pregnancy, without a history of spontaneous (s)PTB < 34 weeks of gestation and a mid-trimester cervical length ≤ 35mm were eligible. After informed consent, women were randomized (stratified per hospital) in a 1:1 ratio to either an Arabin pessary or vaginal progesterone (200 mg daily). Primary outcome was composite adverse perinatal outcome. Secondary outcomes were rates of (s)PTB before 37, 34, 32 and 28 weeks. Sample size was set at 628 women. Analysis was by intention-to-treat. We calculated relative risk (RR) and 95% confidence intervals (CI). Between July 2014 and March 2022, we randomized 304 women to pessary and 312 to progesterone. Baseline characteristics were comparable. The primary outcome occurred in 6.3% in the pessary group compared to 5.2% in the progesterone group (crude RR 1.2 95% CI 0.64 - 2.3, corrected RR 1.2 95%CI 0.62 – 2.2). Regarding the secondary outcomes, the rates of (s)PTB before 37, 34 and 32 weeks were comparable in both groups. The difference in rates of (s)PTB before 28 weeks was more prominent in favor of progesterone. In a predefined subgroup of women with a cervix ≤ 25mm, both PTB < 28 weeks (20.0% vs 6.2%, RR 3.3, 95 % CI 1.1 – 9.5) and sPTB < 28 weeks (16.7% vs 4.6%, RR 3.6, 95% CI 1.0 – 12.5) were higher in the pessary group. In women with a singleton pregnancy and a mid-trimester cervical length ≤ 35mm, we found no superiority of pessary over progesterone or vice versa in the prevention of a composite adverse perinatal outcome. However, (s)PTB rates < 28 weeks were higher in the pessary group, especially in the subgroup with a cervix ≤ 25mm.View Large Image Figure ViewerDownload Hi-res image Download (PPT)