RÉSUMÉ
OBJECTIVE: The aim of the study was to investigate prospective, longitudinal associations between maternal prenatal cortisol response to an interpersonal stressor and child health for the subsequent 3 years. METHODS: One hundred twenty-three women expecting their first child provided salivary cortisol samples between 12 and 32 weeks of gestation (M (SD) = 22.4 (4.9) weeks) before and after a videotaped couple conflict discussion with their partner. Mothers reported on overall child health and several indicators of child illness (sick doctor visits, fevers, ear, and respiratory infections) when children were 6 months (n = 114), 1 (n = 116), and 3 (n = 105) years old. Associations between maternal prenatal cortisol reactivity and recovery and later child health at each of the three time points were analyzed using longitudinal regression models. RESULTS: Greater cortisol reactivity in response to the couple conflict discussion was associated with maternal self-report of better overall child health (p = .016, 95% CI = 0.06-1.30, Cohen's f = 0.045) across the study period. Greater cortisol reactivity was also associated with lower incidence rate ratios for maternal reports of sick doctor visits (incidence rate ratio 95% CI = 0.25-0.83, p = .006), fevers (95% CI = 0.25-0.73, p = .002), ear infections (95% CI = 0.25-0.58, p < .001), and respiratory infections (95% CI = 0.08-1.11, p = .073). Cortisol recovery was unrelated to study outcomes (all p's > 0.05). Maternal prenatal depressive symptoms moderated the association between cortisol reactivity and overall child health (p = .034, 95% CI = 0.07-1.87 for interaction term) but no other health outcomes (p's > 0.05). Among women with lower depressive symptoms, cortisol reactivity was not associated with overall child health; among women with higher levels of depressive symptoms, greater cortisol reactivity was associated with better overall child health. CONCLUSIONS: This study provides longitudinal evidence that greater maternal cortisol reactivity to a salient interpersonal stressor during pregnancy is associated with fewer child health problems and better maternal report of overall child health during infancy and into early childhood. TRIAL REGISTRATION: Clinicaltrials.gov ID NCT01901536.