The Impact of Inflammatory Cytokines on Recurrent Pregnancy Loss: A Preliminary Investigation

Abstract

Recurrent pregnancy loss (RPL), defined as two or more consecutive miscarriages before 20 weeks of gestation, affects 1–2% of couples worldwide. Pro-inflammatory cytokines, such as TNF-α, IL-1β and IL-6 play critical roles in early pregnancy, while anti-inflammatory cytokines like TGF-β and IL-10 promote immune tolerance to prevent harmful inflammatory responses that play important role in placental and fetal development. This aim of the study is to analyse the levels of inflammatory cytokines in blood serum from RPL patients and healthy women (control). The measured cytokines included TNF-α, IL-6, IL-10, TGF-β, CRP, ferritin, IL-1β and IL-4, IFN-γ and IL-17. Using an unpaired t-test and Pearson correlation, significant difference observed between the groups. The results had significantly elevated CRP levels with decreased levels of TGF-β and ferritin (p < 0.05), whereas, IL-1β and IL-4 also found raised indicating a link between systemic inflammation and recurrent miscarriages. IL-4 and CRP increase further suggest potential oxidative stress role in RPL cases. However, no significant differences observed in IL-10, IL-6, or TNF-α level between the groups. This study highlights immune dysregulation as possible contributors to early pregnancy loss, with significant increases in CRP, IL-1β, and IL-4 levels indicating an imbalanced immune response at the maternal–fetal interface. These cytokine elevations may disrupt immune tolerance, suggesting the need for further exploration into cytokine interactions in pregnancy and their potential as an investigatory biomarker and therapeutic target in RPL. © The Author(s), under exclusive licence to Society for Reproductive Investigation 2025.