ABSTRACT: In a prospective longitudinal study, 202 primigravidas were assessed for depression using the National Institute of Mental Health's (NIMH) standardized clinical interview, the Schedule for Affective Disorders and Schizophrenia (SADS), and Research Diagnostic Criteria (RDC) at four periods: 10 to 14 weeks of pregnancy, 30 to 32 weeks of pregnancy, 1 to 2 weeks postpartum, and 14 weeks postpartum. Women's responses did not fit the SADS standardized questions and prescribed ratings because pregnancy and postpartum symptoms often mimicked depression symptoms. This was addressed by adding questions and scoring criteria to separate out pregnancy and postpartum symptoms from depression symptoms. Results showed that, after accounting for pregnancy-postpartum symptoms, women consistently claimed eight symptoms with high frequency and higher mean ratings: dysphoric mood, worrying, somatic and psychic anxiety, insomnia, fatigue, anger, and irritability. The findings suggest that 1) depression in pregnant and newly delivered women may be underdiagnosed if caregivers attribute their complaints or symptoms to time-limited somatic conditions; 2) depression may be overdiagnosed if clinicians use self-report measures solely, or without carefully interviewing women to separate the symptoms of depression from symptoms of pregnancy and postpartum; and 3) women's reactions to perinatal symptoms may have some bearing on the development of depression then or later. Simple clinical and social amelioration of the symptoms of distress might reduce their effect and diminish the rate of mistaken diagnoses of depression.