Symptoms of major depressive disorder (MDD) include persistent sad mood, feelings of hopelessness or guilt, decreased energy, irritability, and more. If untreated, MDD can interfere with the ability to work, study, sleep, eat, and enjoy once pleasurable activities. MDD occurs most commonly in females between the ages of 25 and 44. This puts women of childbearing age at a particularly high risk for developing the disorder. However, very little research has been done to determine the safety of antidepressant use during pregnancy and how the medication may affect the baby. This study will determine the safety of antidepressant use during pregnancy for both the mother and the child.

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.

At birth, cord blood will be collected and the infant's cries will be recorded. The infant's development will be assessed at 2 weeks and 3, 6 ½, 12, 18, and 24 months postpartum. Mothers who take selective serotonin reuptake inhibitors (SSRIs) and are breastfeeding their children will report to the study site with their children at 1 month postpartum to measure the level of SSRIs in the infant's blood. In addition, digital photographs of the infant's face, profile, hands, and torso will be taken at 2 weeks and 3, 12, and 24 months postpartum. Additional face-only photographs of the infant will be taken at these times and at birth for further in-depth analyses of facial characteristics. Mother-child interactions will be videotaped at all postpartum assessments.