A Longitudinal EMA Study Examining the Role of Maternal Mood and Physical Symptoms on Women's Cannabis Use Across the Perinatal Period - Abstract Cannabis is the most widely used drug among pregnant women, and rates of use are increasing dramatically. Reasons for the sharp increase in cannabis use (CU) among in perinatal women are not clear. Changes in cannabis legalization, increased access and acceptability of the drug, and a perception of low health risk or therapeutic benefit are possible explanations. Increased CU for medicinal reasons in the general population may prompt women to consider CU for pregnancy symptoms, such as nausea. Further, symptoms of anxiety and depression are common during the perinatal period, and some women may turn to cannabis if it is perceived to be less risky, or more acceptable, than standard psychopharmacologic treatments. Yet adverse outcomes have been documented, including higher incidence of low birth weight, greater need for neonatal intensive care admission, and a 3-fold risk of neonatal morbidity. Mothers who use cannabis prenatally experience higher rates of depression; among postpartum users, there is also a greater risk for depression and as well as lower likelihood of breastfeeding. Not all women who use cannabis prior to pregnancy continue during the perinatal period. Some data suggest that 2/3 of women discontinue CU upon learning of pregnancy, with up to 1/3 continuing use. Our data show that many women who continue CU express conflicted feelings about their use. Among those who quit, relapse is not uncommon, especially after delivery. Reasons for continued CU during the perinatal period, and motivations for cessation, are relatively unknown. In light of the widespread CU during the perinatal period, a critical need exists to develop tailored interventions, services, and educational materials, particularly addressing the needs of pregnant women with high levels of mood and physical symptoms. However, before interventions and services can be developed, it is crucial to elucidate pregnant women’s motives for CU, predictors of use and cessation, the extent to which mood and physical symptoms drive patterns of use, as well as the salience of contextual factors (e.g., access to cannabis). Utilizing a framework based on socioecological models of health behavior, we propose to examine factors that contribute to women’s CU behavior in the perinatal period. In this 5-year study, we will recruit 200 pregnant women who report regular CU immediately prior and/or during pregnancy and follow them from the first trimester of pregnancy to 12 weeks postpartum. We include 4, 10-day bursts of ecological momentary assessment (EMA) during the perinatal period to track associations between maternal mood and physical symptoms, CU, and cannabis cravings. Further, we will conduct qualitative interviews with women to elicit feedback regarding ideal content and modality of future services and interventions. Quantitative and qualitative results will be integrated to yield cohesive findings to guide future research and service development. Tailored support for women may reduce deleterious outcomes associated with CU during the perinatal period.