Maternal-Fetal Interplay During Mid-gestation: Inflammatory Biomarker Levels in Maternal Sera, Cord Sera and Placenta

Maternal inflammation is linked to adverse maternal and fetal outcomes, but how maternal inflammation affects fetal inflammation during mid-gestation is not known.

We measured 20 biomarkers of inflammation, including chemokines, pro-and anti-inflammatory cytokines, and immunomodulatory cytokines, in matched maternal and cord sera and placental tissue collected during the second trimester from a diverse cohort (N = 106). We examined trends in biomarkers across the second trimester using a linear trend test, and compared distributions across sociodemographic groups using a Kruskal-Wallis test. We calculated Spearman correlation coefficients and stratified the correlation matrices by gestational age at sample collection (<20 vs. ≥ 20 gestational weeks).

Most inflammatory biomarkers did not exhibit clear trends with gestational age, except for cord levels of CCL17 and CCL22; both Th2-associated chemokines significantly increased across the second trimester. There were no consistent patterns in biomarker levels across sociodemographic groups. Overall, correlations among maternal, placental and cord biomarkers were stronger before 20 weeks' gestation than in later pregnancy. While correlations between maternal and placental CCL17 declined after 20 weeks, the correlation between placental and cord CCL17 increased during this same period.

Maternal and fetal inflammatory responses are more tightly coordinated earlier in the second trimester.