Prediction Of Preterm Birth And Adverse Perinatal Outcomes After Cervical Pessary Placement In Singleton Pregnancies With Short Cervical Length

Objectives: To identify ultrasound-assessed cervical characteristics, modified after pessary placement, which could be predictive of spontaneous preterm birth (sPTB) at < 34 weeks of gestation (WG) or severe adverse perinatal outcomes (APO). Study design: This prospective observational study conducted at Vall d'Hebron Universitary Hospital assessed multiple cervical characteristics in women with short cervical length (CL). All participants were examined by transvaginal ultrasound before and immediately after a cervical pessary was placed. Cervical assessment included CL, uterocervical angles (UCA), and cervical consistency indexes (cervical consistency index (CCI) and cervical length consistency index (CLCI)). Pregnancy outcomes were recorded to determine the capacity of these variables for predicting sPTB at < 34 WG and severe APO. Results: Thirty-one women with short CL, 17 (54.8%) with asymptomatic midtrimester short CL, and 14 (45.2%) after arrested threatened preterm labor were enrolled. After pessary placement, transvaginal ultrasound detected four participants in whom the pessary was not correctly placed around the cervix (12.9%); additionally, significant changes were observed in most cervical baseline characteristics, with CL, anterior UCA (A-UCA), CLCI, and intersegmentary angle (ISA) being predictive of sPTB at <34 WG and severe APO. Receiver operator curves were calculated to compare the predictive capacity of these variables, with CL and A-UCA after pessary placement being the best predictive parameters with an area under the curve of 0.88 and 0.87, respectively. Conclusions: Transvaginal ultrasound after pessary placement detects incorrect pessary placement after pessary insertion and during follow-up. APO and sPTB can be predicted by measuring CL, A-UCA, CLCI, and ISA immediately after pessary placement, being CL and A-UCA more accurate and easier to be measured. Our results help to better identify women in whom the pessary is more likely to fail. Further research is required to assess the effectiveness of applying alternative, sequential or additional treatments to reduce prematurity and our results could be considered when designing such studies.