The Influence of Maternal Inflammatory Status on Fetal Telomere Length at Birth.

: Fetal telomere length (FTL) at birth is considered a key marker of early biological aging and future disease risk. While chronic inflammation is known to accelerate telomere attrition in adults, limited evidence exists on how maternal inflammation during pregnancy impacts FTL. This study aimed to investigate the association between maternal systemic inflammatory status in late pregnancy and FTL at birth. : We conducted a prospective cohort study including 150 clinically healthy pregnant women recruited in the third trimester. Participants were stratified post hoc into an inflammation group (n = 67) and a control group (n = 83) based on circulating inflammatory markers: high-sensitivity C-reactive protein (hsCRP), interleukin-6 (IL-6), TNF-α, and IL-10. Umbilical cord blood was collected at birth, and telomere length was quantified using real-time PCR. Correlation and multivariable linear regression analyses were performed to evaluate associations between maternal inflammation and FTL. : Mothers in the inflammation group had significantly elevated hsCRP, IL-6, and TNF-α levels, and lower IL-10 concentrations. FTL was significantly shorter in this group compared to the controls. Unlike previous investigations that relied on single pro-inflammatory markers, our study tests a composite immune-balance index (IL-6/IL-10 ratio) together with hsCRP in a prospectively followed cohort of clinically healthy pregnancies. Using its correlation coefficient, the IL-6/IL-10 ratio alone explained approximately 28% of the total variance in fetal telomere length-almost double the variance captured by IL-6 assessed in isolation. IL-6 and hsCRP emerged as independent negative predictors of FTL in multivariable models (β = -0.37 and -0.29, respectively). The IL-6/IL-10 ratio showed the strongest inverse correlation with FTL (r = -0.53, < 0.001). : Subclinical systemic inflammation in late pregnancy is independently associated with shorter fetal telomere length at birth, highlighting maternal immune imbalance (especially IL-6/IL-10 ratio) as a modifiable determinant of early biological aging. These findings underscore the need to consider maternal inflammatory profiling in pregnancy as a potential target for early-life preventive strategies.