6 - Randomized Trial of Cervical Pessary for Short Cervix in Singleton Pregnancies

We performed a randomized multicenter trial comparing a cervical pessary versus usual care in non-anomalous singleton pregnancies with a transvaginal ultrasound measurement of a cervical length of <20 mm from 14 weeks 0 days through 23 weeks 6 days. Women with a prior spontaneous preterm birth were excluded. Our primary outcome was birth prior to 37 weeks or fetal death at any time. Use of vaginal progesterone was at the discretion of the treating clinician.

Results: Although the planned enrollment was 850, following a prespecified interim analysis, the study was stopped after recruiting 544 (64%) participants for a potential safety concern for perinatal mortality in addition to futility. Baseline characteristics were balanced between the groups, including the near universal receipt of progesterone (Table 1).  In an intention to treat analysis, the primary outcome occurred in 45.5% of people who received a pessary and 45.6% who received usual care (RR1.00- 95%CI 0.83-1.20). The proportion of participants remaining pregnant at each gestational age did not differ between groups (p = 0.46; Figure 1). Neonatal or fetal death occurred in 13.3% of women who received a pessary and 6.8% who received usual care (RR 1.96-95% CI 1.14-3.35).  Other outcomes were similar between the two groups.

Conclusion: Placement of a cervical pessary in singleton gestations with a cervical length <20mm did not decrease the risk of preterm birth. The higher rate of neonatal or fetal death needs further investigation of contributing factors.