Cellular dynamics of cervical remodelling: insights from preterm and term labour.

Introduction: Preterm birth remains a global health challenge with significant perinatal morbidity and mortality rates. Despite extensive research, the underlying mechanisms triggering preterm birth remain elusive, needing a deeper understanding of cervical cellular remodelling processes.

Purpose: This study aims to elucidate the cellular mechanisms underlying cervical remodelling in spontaneous preterm labour (PTL) compared to term labour (TL), focusing on the roles of inflammatory cells and fibroblasts.

Methods: We conducted a prospective observational study from October 2018 to March 2021, at two hospitals. Participants were categorized into two groups: PTL (n = 14), TL (n = 14). A small set (n = 6) of preterm not in labour (PTnotL) was also included. Cervical biopsies were obtained and analysed for the density of fibroblasts and inflammatory cells (neutrophils and mononuclear cells) using digital image analysis. Statistical analysis was performed employing Mann-Whitney and Kruskal-Wallis tests.

Results: There was no significant overall difference in global inflammatory cell density between PTL and TL (p = 0.154). However, a detailed analysis revealed significantly higher inflammation in the exocervix of PTL compared to TL, particularly involving neutrophils (p = 0.021) and mononuclear cells (p = 0.028). Neutrophils (p = 0.035), but not mononuclear cells (p = 0.111), were significantly decreased in PTnotL exocervix compared to PTL. No differences were found in inflammatory cell density in the endocervix. Fibroblast densities were similar across groups.

Conclusions: This study highlights the distinct cellular profiles in the cervix during preterm and term labour, with neutrophils playing a pivotal role in preterm labour. These findings may guide the development of targeted interventions to prevent preterm birth.