Maternal Prenatal Psychosocial Stress and BMI Predict Lower Fetal Iron Status in a Mexico City Cohort (FS01-07-19)

Abstract

ObjectivesInsufficient iron in utero may impair neurocognitive development. Prenatal physiological stress, as in obesity, inhibits fetal iron accumulation. Emerging evidence suggests prenatal psychosocial stress may similarly suppress fetal iron, a novel potential mechanism linking prenatal stress and child neuro-cognition. In a pregnancy cohort in Mexico City, Mexico, we investigated associations between maternal prenatal stress and psychological function, pre-pregnancy BMI and fetal iron at delivery. We hypothesized that maternal prenatal psychosocial stress and psychological dysfunction and pre-pregnancy BMI would be associated with lower cord blood Hb and ferritin. MethodsPsychosocial stress and psychological function were assessed with validated questionnaires in mid-pregnancy: depression symptoms (CES-D), trait anxiety (STI), perceived stress (PSS-4), lifetime exposure to violence (ETV), and negative life events (NLEs, CRISYS). Pre-pregnancy BMI was calculated from self-reported height and weight. Cord blood was collected at delivery and ferritin (ferr.) and hemoglobin (Hb) measured. Regression models were developed for Hb and log-transformed ferr. as functions of dichotomized stress scores (CES-D ≥ 13, STI > median, PSS-4 > 4th quartile, ETV > 0.5, CRISYS > 1st quartile) and pre-pregnancy overweight and obesity in separate models, each adjusted for maternal age, SES, child sex and maternal prenatal iron supplementation (yes/no). ResultsIn 455 dyads with complete data, median (IQR) ferr. and Hb were 186 μg/L (125, 265) and 16 g/dL (14.7, 17), respectively. In adjusted models, lower ferr. was associated with prenatal depression symptoms (11%, 95% CI: –0.26, 0.01), elevated perceived stress (23%, –0.35, –0.09), high lifetime violence (21%, –0.33, –0.06) and high NLEs count (10%, –0.22, 0.02), as well as maternal pre-pregnancy obesity (17%, –0.31, –0.00). Interaction models suggested possible stronger prenatal stressor effects among overweight and obese mothers. No associations with cord blood Hb were observed. ConclusionsIn Mexico City pregnant women, excess pre-pregnancy BMI and multiple prenatal psychosocial stressors were each associated with fetal iron stores at birth. Insufficient fetal iron accrual may explain links between maternal prenatal stress and child neurocognitive development, but more research is needed. Funding SourcesNational Institutes of Health, Office of the Director; National Institute of Environmental Health Sciences.