Utility of cervical pessary in the prevention of preterm birth in triplet pregnancies: A single-center observational retrospective study of 165 triplet pregnancies

Objective: Premature births are a health problem arising in triplet pregnancies, resulting in high levels of morbidity and mortality. The objective of this study is to evaluate the utility of cervical pessaries in reducing prematurity (<34 weeks) in triplet pregnancies. Methods: This is a single -center, retrospective case-control study regarding triplet pregnancies with follow-up at the La Paz University Hospital between 2000 and 2023. Maternal characteristics, obstetric and perinatal outcomes, and the use of cervical pessaries were examined. Results: 165 triplet pregnancies were analyzed: 87 (52.7 %) in the case group (premature triplet pregnancies) and 78 in the control group (non-premature triplet pregnancies). A cervical pessary was inserted in 15 (17.2 %) triplet pregnancies in the case group and in 12 (16.7 %) triplet pregnancies in the control group (p = 0.92; OR = 1.04 (0.46-2.35)). A pessary was later inserted in the non-premature group (p = 0.01). The risk of preterm labor and the use of tocolytics +/- glucocorticoids were found to be significantly more frequent in the premature group, with p = 0.01; OR = 2.30 (1.21-4.36) and p < 0.01; OR = 2.36 (1.23-4.44), respectively. Protocol-based cesarean sections were more frequent in the non-premature group (p < 0.01), while cesarean sections due to maternal complications (p < 0.01) and premature membrane rupture (p < 0.01) were more frequent in the premature group. Conclusion: The cervical pessary is not useful in preventing preterm births (< 34 weeks) in triplet pregnancies. It is likely that being pregnant with triplets is a powerful independent factor associated with prematurity, despite other pregnancy conditions. Women who are pregnant with triplets and at risk of preterm labor and those taking tocolytics +/- glucocorticoids may benefit from pessary insertion.