Potential participants in the study will be screened for eligibility during their third trimester of pregnancy, using a combination of questionnaires. Those who are eligible for participation will have one blood sample drawn at this time, and then be asked to complete a follow up questionnaire at 4-6 weeks postpartum to assess for depressive mood symptoms. This follow up questionnaire can be completed either in person or on the telephone. Anyone who is interested in receiving help for their mood at any point in the study will receive referrals.