Cervical pessaries fail to prevent preterm birth among individuals with short cervix

In an effort to address the established risk of preterm birth associated with a short cervix, a recent study published in the Journal of Association Medical Association found that cervical pessaries did not reduce the risk of preterm delivery, it was associated with an increased risk of fetal or neonatal/infant mortality.

Conducted between February 2017 and November 2021 across 12 centers in the US, the randomized, unmasked trial enrolled nonlaboring individuals with singleton pregnancies and a transvaginal ultrasound cervical length of 20 mm or less at gestations of 16 weeks 0 days through 23 weeks 6 days. Notably, individuals with a prior spontaneous preterm birth were excluded from the study.

A total of 544 participants were enrolled in the study, representing 64% of the originally planned sample size of 850. The mean age of participants was 29.5 years. Half of the participants were randomly assigned to receive a cervical pessary, while the other half received usual care. Additionally, 98.9% of the participants received vaginal progesterone at the discretion of their treating clinicians.

The primary outcome of interest was the occurrence of delivery or fetal death prior to 37 weeks of gestation. Surprisingly, the results of the study did not show a significant difference in the risk of preterm birth between those who received a cervical pessary and those who received usual care. The primary outcome occurred in 45.5% of participants who received the pessary and 45.6% of those who received usual care, with a relative risk of 1.00.

However, the study's most concerning finding was related to fetal or neonatal/infant mortality rates. Among those who received the cervical pessary, the rate of fetal or neonatal/infant death was 13.3%, compared to 6.8% in the usual care group. This resulted in a relative risk of 1.94, indicating a higher mortality risk associated with the pessary.

Due to these concerning findings and the interim analysis results, the study recruitment was halted. The researchers expressed concerns over both fetal/neonatal mortality and futility, highlighting the lack of significant benefit in using cervical pessaries to prevent preterm birth in the specific group of nonlaboring individuals with a singleton pregnancy and a short cervix.

Reference:

Hoffman, M. K., Clifton, R. G., Biggio, J. R., Saade, G. R., Ugwu, L. G., Longo, M., Bousleiman, S. Z., Clark, K., Grobman, W. A., Frey, H. A., Chauhan, S. P., Dugoff, L., Simhan, H. N., Esplin, M. S., Macones, G. A., … Bickus, M. T. (2023). Cervical Pessary for Prevention of Preterm Birth in Individuals With a Short Cervix. In JAMA (Vol. 330, Issue 4, p. 340). American Medical Association (AMA). https://doi.org/10.1001/jama.2023.10812