The pregnancy and postpartum periods are times of remarkable emotional and physical change for a woman, making pregnant women more vulnerable to mood swings and depressive symptoms. It is estimated that approximately 10% to 15% of pregnant women experience depression, which can cause severe psychological distress for the woman as well as disturbances in infant development. Infants of depressed mothers are at a higher risk for developmental delays, behavioral problems, and difficulty eating and sleeping. Moreover, new data indicate that prenatal depression also may adversely affect brain development of the child even before birth. Despite the high prevalence rates of prenatal depression and its negative consequences, few studies have tested the effectiveness of interpersonal psychotherapy (IPT), a treatment for depression that focuses on interpersonal issues and relationships, during pregnancy. The administration of group prenatal IPT for depression may be effective in enhancing women's prenatal and postpartum moods and improving fetal and newborn functioning. This study will compare the effectiveness of group IPT with that of treatment as usual (TAU) for preventing postpartum depression in pregnant women with depression and for improving healthy outcomes in their babies. The study will also compare the fetal and newborn development of babies of healthy mothers with that of babies of depressed mothers.

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.

Participants found to be depressed on the first visit will then be assigned randomly to receive group IPT or TAU. Participants assigned to group IPT will attend 12 weekly psychiatrist-led sessions that will focus on overcoming relationship problems associated with depression. The first two and last sessions will be alone with the psychiatrist and the remaining sessions will be with a group of five to eight other pregnant women. Participants assigned to TAU will be referred to outpatient treatment, which may include cognitive behavioral psychotherapy, insight-oriented psychotherapy, and/or antidepressant medication. TAU participants receiving psychotherapy will attend 12 weekly treatment sessions comparable to the IPT group sessions; treatment for TAU participants receiving antidepressant medication may last longer than 12 weeks. During the treatment period, all participants will fill out weekly forms about their moods and will have monthly interviews with a psychiatrist. Upon completion of treatment, participants will have a 30-minute final evaluation meeting.

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.