 This study will involve both healthy participants and participants with depression. All participants will start with an initial assessment visit between the 22nd and 23rd weeks of pregnancy. For participants who have shown signs of depression based on an initial phone interview, the initial visit will last about 2 hours and will include questions about medical and psychiatric history, depressive symptoms, and lifestyle habits and an examination of uterine blood flow using a Doppler ultrasound machine. Participants who do not show signs of depression will not undergo these assessments on the initial visit. 