Symptoms of depression in late pregnancy are associated with increased salivary alpha-amylase levels

Purpose
Prenatal depression increases risk for a number of adverse offspring outcomes, however the biological mechanisms underlying this association remain unclear. It has been suggested that maternal glucocorticoids may mediate this link, though supporting evidence has been mixed. An alternative mechanism of effect may be via depression-induced changes in maternal sympathetic nervous system (SNS) function. We examined this hypothesis by determining the relationship between symptoms of maternal prenatal depression and diurnal salivary alpha-amylase (sAA) levels.
Methods
76 pregnant women were recruited during either the second or third trimester of pregnancy. Participants self-reported depressive symptoms using the Edinburgh Postnatal Depression Scale. Saliva samples, to be assayed for alpha-amylase activity, were collected at home over two working days.
Results
Participants with depressive symptoms in later pregnancy, had elevated awakening sAA levels compared with non-depressed controls (t(73)=-2.737, p=0.008), and continued to have raised sAA throughout the day (F(1)=10.924, p=0.002).
Conclusions
Our findings highlight that symptoms of depression during late pregnancy are associated with increased maternal SNS activity. Thus, changes in maternal SNS function, which may include increased vasoconstriction and reduced fetal blood flow, could, in part, mediate associations between prenatal depression and adverse offspring outcomes.