Maternal prenatal psychological distress (PD) can steer offspring development through adaptations in fetal programming. Maternal systemic cortisol levels are hypothesized to be a major mechanism in transmitting distress signals and hair cortisol concentrations (HCC) can be a proxy measure for the individual’s long-term cortisol exposure. The aims of this doctoral thesis were to systematically review the literature on the associations between maternal prenatal PD and HCC (Study I) and to investigate the associations of maternal prenatal HCC with maternal PD (Study II) and with child socioemotional problems (Study III).

Studies II and III were conducted among FinnBrain Birth Cohort Study subjects with maternal HCC measurements from either gestational week 24 (HCC1, n = 467) or 1–3 days after delivery (HCC2, n = 222) and with relevant questionnaire data (a selection of maternal prenatal PD measures for Study II and maternal reports of child socioemotional problems at 2 and 5 years for Study III; n = 321 for HCC1 and n = 121 for HCC2).

Associations between maternal prenatal PD and HCC were inconsistent in the six studies included in the systematic review (Study I). In Study II, concurrent PD was not associated with HCC, but elevated maternal HCC2 associated with trajectories of chronically elevated maternal prenatal depressive symptoms. Lower maternal HCC2 was associated with increased overall child socioemotional problems at a child’s age of 2 years and an increase in internalizing symptoms at 2 and 5 years in Study III. HCC1 is only associated with symptoms in girls, and the interaction between maternal PD and HCC2 was associated with child symptoms.

Novel evidence on maternal prenatal HCC presented here advances research assessing concurrent maternal mood and problems in child socioemotional development. Methodology has an impact on explaining whether associations between HCC and PD can be observed and the relevance of also lower maternal prenatal HCC on child outcomes should be acknowledged. Longitudinal and multidisciplinary study designs are essential to elucidate the mechanisms and clinical relevance of the offspring outcomes.