Introduction: Maternal antenatal stress/depression is associated with increased risk of offspring emotional and behavioural problems. However, the extent of causality and potential mediating mechanisms are unclear.
Objectives: This thesis investigates several questions including: (1)To what extent is the association between maternal antenatal stress/depression and offspring adolescent anxiety causal? (2)Is maternal antenatal stress/depression associated with altered placental gene expression? (3)Is maternal antenatal stress/depression associated with altered infant’s HPA-reactivity/temperament and is this mediated through placental mechanisms?
Methods: Two studies were conducted. The first used parental antenatal psychometric measures and offspring anxiety diagnoses at age 18 from the ALSPAC Study. The second study included a cohort of 90-pregnant women. At birth, maternal psychological symptoms and placentae were collected. At 4-months postpartum, mother-infant dyads undertook assessments collecting maternal psychological symptoms and infant behaviour reports. Saliva samples were collected in response to the Still Face Paradigm.
Results:
In study 1: Maternal antenatal depression was associated with increased risk of offspring anxiety diagnosis(adj.OR1.75(1.19,2.58)). No risk increase was observed with paternal depression.
In study 2: Maternal antenatal stress/depression was associated with altered placental gene expression of 11-HSD2 (decrease), MAO-A (decrease) and NR3C1 (increase), but only in Caucasians. Maternal antenatal stress/depression was also associated with increased infant baseline cortisol and HPA-reactivity. Gender-dependent effects on offspring outcome were observed following antenatal depression; females had greater infant HPA-reactivity, males had increased negative temperament. No clear evidence of placenta-mediated effects was observed.
Conclusions: This thesis provides new evidence that maternal, but not paternal, antenatal depression is associated with offspring anxiety. Maternal depression/stress was associated with altered placental gene expression but only in Caucasians. This comparison of Caucasian and non-Caucasian participants is a novel finding. Finally, the findings also suggest possible differences by child gender in the associations between maternal antenatal depression/stress and infant outcomes. This requires further exploration in future studies.