 All participants, including healthy participants, will be asked to attend two sessions focused on their babies development, one occurring between the 36th and 38th weeks of pregnancy and one shortly after giving birth. During the first developmental session, participants will complete a questionnaire about mood; undergo heart rate, breathing, and blood pressure monitoring; undergo an ultrasound; and perform a word matching task. The second developmental session will occur between 20 and 30 hours after birth of the baby and will include a newborn testing session that will consist of physiological and neurobehavioral assessments. Healthy participants study participation will be over upon completion of the second developmental session. Depressed participants will be contacted by phone once every 2 weeks for 6 months after giving birth. 