Endometriosis as an independent risk factor for preterm birth: a systematic review and meta-analysis of cohort studies

Abstract This systematic review and meta-analysis evaluated the association between endometriosis and preterm birth (< 37 weeks). PubMed, Embase, Web of Science, and Cochrane Library were searched through May 2025 for cohort studies. Two investigators independently extracted data and assessed risk of bias using risk of bias in non-randomized studies of interventions (ROBINS-I) and grading of recommendations assessment, development and evaluation (GRADE). Adjusted effect estimates were pooled using a random-effects model. We included 24 studies that involved over 25 million women. Endometriosis was associated with an increased risk of preterm birth (RR = 1.36, 95% CI 1.26–1.46; I² = 85.2%). Subgroup analyses showed increased risk in women who conceived via assisted reproductive technology (ART) (RR = 1.24, 95% CI 1.11–1.38, I2 = 54.8%) and in women who conceived spontaneously (RR = 1.44, 95% CI 1.28–1.62, I2 = 36.3%). The association remained consistent across studies with different designs and diagnostic criteria. In the surgically confirmed subgroup (RR = 1.21, 95% CI 1.06–1.39, I² = 0.0%) the association remained significant. Findings remained robust after adjustment for maternal age, parity, and BMI. Current evidence indicates a consistent association between endometriosis and preterm birth, although substantial heterogeneity is observed across the studies. Pregnant women with confirmed endometriosis should receive enhanced prenatal monitoring and risk assessment. This study was registered in PROSPERO (CRD42025100583). Funding This work was supported by: 1. National Natural Science Foundation of China (NSFC) Regional Project (grant no.81760266). 2. Supported by Guizhou Provincial Basic Research Program(Natural Science)(No: (2020)1Y307). Author information Authors and Affiliations Corresponding authors Ethics declarations Competing interests The authors declare no competing interests. Additional information Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. Supplementary Information Below is the link to the electronic supplementary material. Rights and permissions Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/. About this article Cite this article Li, G., Huang, K., Wang, W. et al. Endometriosis as an independent risk factor for preterm birth: a systematic review and meta-analysis of cohort studies. Sci Rep (2026). https://doi.org/10.1038/s41598-026-65907-5 Received: Accepted: Published: DOI: https://doi.org/10.1038/s41598-026-65907-5