Pre-pregnancy body mass index and biomarkers of inflammation at birth.

BACKGROUND

High pre-pregnancy body mass index (BMI), accompanied by chronic low-grade inflammation may predispose offspring to adverse health outcomes by interfering with fetal development. However, the association between maternal pre-pregnancy obesity and elevated inflammatory biomarkers in the mother or fetus remains controversial. This study analyzed the association between pre-pregnancy BMI and biomarkers of inflammation in maternal serum and cord blood at birth in two large birth cohorts.

METHODS

Pre-pregnancy weight and height were used to calculate pre-pregnancy BMI (underweight [<18.5 kg/m²]; normal [18.5-24.9 kg/m²]; overweight [25.0-29.9 kg/m²]; obese [≥30 kg/m²]). Biomarkers of inflammation (interleukin [IL]-1β, IL-6, IL-10, tumor necrosis factor α [TNF-α]) were measured from maternal serum collected at birth in ELFE (n = 1046) and cord blood collected in both cohorts (EDEN [n = 856 for cytokines]; ELFE [n = 1016]) C-reactive protein (CRP) was additionally measured in the cord blood of both cohorts (EDEN: n = 820; ELFE: n = 1012]). Linear regression models were used to determine the association between BMI categories with biomarker levels, adjusting for confounders.

RESULTS

In ELFE, pre-pregnancy obesity was strongly and positively associated with cord blood CRP (adjusted β 0.52 [95% CI 0.32, 0.72]), while in EDEN, maternal overweight was associated with higher levels of cord blood CRP (0.32 [0.12, 0.54]). In ELFE, maternal underweight was also associated with higher levels of cord blood IL-10 in cord blood (0.20 [0.04, 0.35]). Pre-pregnancy BMI was not associated with any of the maternal serum biomarkers in ELFE in the overall analyses.

CONCLUSIONS

High pre-pregnancy BMI was associated with elevated CRP levels in cord blood, reflecting higher inflammatory marker levels in the perinatal environment. These findings should be replicated in other large cohort studies. The potential implications of elevated prenatal inflammation on offspring outcomes warrant further investigation.