Association of iron status with gestational diabetes and preeclampsia in an obesogenic context: Results from a cohort of pregnant Chilean women.

PURPOSE: Elevated maternal iron biomarkers may promote oxidative stress and inflammation, contributing to metabolic alterations that, alongside obesity, increase the risk of gestational diabetes (GDM), preeclampsia, and macrosomia. This study assessed associations of maternal hemoglobin (Hb), hematocrit (Hct), serum ferritin (SF), and soluble transferrin receptor (sTfR) with these outcomes, in a population with low anemia and high maternal obesity prevalence.

STUDY DESIGN AND

METHODS

This prospective cohort included 1730 pregnant women from the CHiMINCs-II study in Santiago, Chile, with Hb or Hct measured in the first or second trimester. SF and sTfR were assessed in a random subsample of 350 second-trimester samples. Multivariate logistic regression models evaluated associations between iron biomarkers and maternal and neonatal outcomes.

RESULTS

Elevated Hb ( > 13 g/dL) occurred in 50% of women in the first trimester and 12% in the second. Anemia prevalence was <10% in the first and second, and 38% had depleted iron stores (SF concentration <15 µg/L). GDM, preeclampsia, and macrosomia prevalence were 17%, 3.3%, and 7.1%, respectively. Higher second-trimester Hb (OR 1.23, 95% CI 1.00-1.52) and Hct (OR 1.09, 95% CI 1.01-1.17) were associated with increased odds of GDM. First-trimester anemia was associated with higher odds of preeclampsia (OR 5.67, 95% CI 1.20-27.0). SF and sTfR were not significantly associated with GDM or preeclampsia.

CONCLUSIONS

Despite a high prevalence of depleted iron stores, elevated Hb was also highly prevalent, and associated to adverse maternal outcomes. Optimizing maternal iron status during pregnancy requires addressing both deficiency and potential excess.