PROJECT SUMMARY
Postpartum depression (PPD) is prevalent and associated with negative outcomes for both mothers and
infants. PPD emerges during a period of psychosocial and neurobiological change, and there is a critical need
for integrated research on trajectories of risk processes. Low activation of RDoC’s positive valence systems
(PVS) prospectively predicts depressive symptoms outside of the peripartum period and may be particularly
relevant for driving social motivation in mother–infant relationships. PVS function is reliably and objectively
measured at the neural level, but very little research has examined brain function across pregnancy. Critically,
psychosocial and neurobiological changes occurring across the peripartum period, including acute stress and
elevated cortisol, are also known to impact PVS function. These disparate lines of research support the
scientific premise of low PVS function as a key risk process in PPD and highlight the need to consider
multimethod trajectories of change in PVS function as predictors of PPD, rather than relying on single
measures and time points. We developed safe, feasible, and robust methods for repeatedly assessing reward-
related brain function across the peripartum period, which we will combine with ecological momentary
assessment of positive affect to chart trajectories of PVS function across the peripartum. For comparison,
similar measures of negative valence systems (NVS) function will also be collected. We will recruit 300
pregnant women in their 2nd trimester (at least 50% classified as high risk for PPD) for an intensive longitudinal
study with follow-up assessments conducted every 10 weeks through 25 weeks postpartum (4 lab and 2 virtual
assessments). PVS function will be assessed from 15 weeks gestation to 5 weeks postpartum. Hair samples
will allow for retrospective assessment of cortisol and other hormones to be estimated from conception through
birth, and acute stress and birth trauma will be measured through gold-standard interviews. At 15 weeks
postpartum, mothers and infants will participate in an observed free play interaction to assess mutual
enjoyment. Depressive symptoms and diagnoses will be assessed from 15 weeks gestation through 25 weeks
postpartum. This innovative study will advance understanding of the role of PVS function in PPD, including
examining PVS function as a prospective predictor of PPD, comparing both baseline functioning vs. trajectories
of change and PVS vs. NVS as predictors of depression (Specific Aim 1). We will also test PVS function across
peripartum as a predictor of new mothers’ experiences of enjoyment in interactions with infants and examine
low mutual enjoyment as a mechanism of the effects of low PVS function on PPD (Specific Aim 2). Finally, we
will test longitudinal associations between acute stressors, cortisol levels, and subsequent PVS function,
providing unique insight into the psychosocial and neurobiological processes shaping PVS function, and
ultimately, depression risk (Specific Aim 3). The study will advance understanding of the dynamic interplay of
processes impacting PVS and inform effective timing and targets for intervention to reduce the burden of PPD.