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. 2025 Dec;38(1):2508274.
doi: 10.1080/14767058.2025.2508274. Epub 2025 May 22.

Long-term indomethacin stabilizes the short cervix

Karl Seif  1 , Paola Abi Habib  1 , Bilge Cetinkaya Demir  1 , Sifa Turan  1 , Colleen Driscoll  1 , Christopher Harman  1 , Ozhan Turan  1
Affiliations
Free article

Long-term indomethacin stabilizes the short cervix

Karl Seif et al. J Matern Fetal Neonatal Med. 2025 Dec.
Free article

Abstract

Objective: Short cervical length (CL) is a known predictor of preterm delivery (PTD). We aimed to study the progression of CL as gestational age (GA) advances in patients with short cervix treated under our long-term Indomethacin therapy (LIT) protocol, and to document the effect of LIT on the cervix.

Methods: Retrospective cohort study conducted in a single medical center from 2010 to 2020. Patients with singleton pregnancies and 2nd trimester CL ≤25 mm received LIT per our clinical protocol which included weekly CL and ultrasound (US) surveillance of amniotic fluid and Doppler indices. We compared initial cervical length (CLI) once LIT was started to final cervical length (CLF) once LIT was stopped, and cervical stabilization was defined as CLF-CLI ≥ 0. A longitudinal analysis of CL as GA progressed was performed using a multivariable linear mixed-effects regression model. A subgroup analysis was performed on patients whose total serial CL surveillance period lasted at least 3 weeks, and GA at delivery was analyzed based on cervical stabilization in this initial 3-week period. Statistical analyses were performed using Stata 16.

Results: 135 patients with short CL treated under our LIT protocol were included. 90 (67%) had CLF-CLI ≥ 0. Based on the regression model, the rate of CL change with time was 0.04 mm/day. This did not change when progesterone (both vaginal and intramuscular) use was added as an interaction term. 105 (78%) delivered >32 weeks, and 68 (50%) delivered at full term. There was no difference in the rate of delivery >28 weeks between those with CLI ≤10mm and those with CLI between 11 and 25 mm (78% v 90%, p > 0.05). 112 patients (83%) had at least 3 weeks of US surveillance. Of those, 76 (68%) had CLF-CLI ≥ 0 and 107 (95.5%) delivered at >28 weeks. The PPV of CLF-CLI ≥ 0 to predict delivery >28 weeks was 95%.

Conclusion: While normally CL shortens progressively throughout pregnancy, patients with short CL managed with LIT had no further shortening. There is a need for a randomized controlled trial of LIT for prevention of PTD in patients with short CL.

Keywords: Short cervix; cervical insufficiency; indomethacin; preterm birth; transvaginal ultrasound.

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