Participants in this observational study will not receive medication or treatment of any kind. Pregnant woman who are already taking medication for depression will be recruited, in addition to pregnant women who are not taking any medication. The participants will first undergo interviews to establish their psychiatric diagnoses. Subsequent interviews will be held to monitor levels of depressive symptoms, exposure to other substances that could potentially harm the fetus, levels of antidepressants in the blood, and dietary intake during pregnancy. Participants will report to the study site for these evaluations at Weeks 20, 30, and 36 of pregnancy. From Week 36 to Week 40, interviews will be conducted over the phone.