Prenatal traumatic stress and offspring hair cortisol concentration: A nine year follow up to the Red River flood pregnancy study

INTRODUCTION

Findings concerning the relationship between maternal prenatal and child cortisol concentrations are inconsistent. This study examined whether the influence of an objective traumatic stressor during pregnancy, distance from a natural flood disaster, moderated the association between prenatal maternal diurnal cortisol and 9-year old offspring hair cortisol concentrations.

METHODS

Data were collected from 56 of the mothers who took part in a study of flood-related pregnancy outcomes in 2009 and their children. Data included distance of the maternal home from evacuation areas, four maternal saliva cortisol assessments (waking, 30 min after waking, afternoon, and before bed) provided within 3-months of the flood crest and child hair samples to assess cortisol secretion over the past month.

RESULTS

There was a significant interaction between proximity to flooding during pregnancy and maternal cortisol AUC predicting child hair cortisol, after controlling for maternal age, gestational age at cortisol sampling, sex of the child, current socioeconomic status and current maternal stress. At greater distance from flooding (lower stress conditions) there was a non-statistically significant positive association between maternal cortisol and child cortisol. In contrast, living closer to flooding (higher stress conditions) produced a significant negative association between maternal and child cortisol.

CONCLUSION

Experiencing a traumatic stressor during pregnancy may alter maternal-fetal programming of the hypothalamic-pituitary-adrenal axis. The direct threat of flooding led to offspring cortisol concentrations that resembled cortisol production seen in mothers with symptoms of PTSD and their offspring. This alteration is evident in nine-year-old offspring and may help explain inconsistencies in the previous literature.