Depression in Swedish women: relationship to factors at birth.

Depression is a common and serious disorder that may have developmental origins. Birth-related factors have been related to childhood and adult occurrence of somatic as well as psychiatric disorders, but studies on the relationship between birth-related factors and depression are few and show mixed results. In addition, varying methods have been used to assess depression. Standardized clinical criteria to diagnose depression, combined with birth data collected from midwife records have not been used in most studies. Participants in the Prospective Population Study of Women in Sweden (803 women), born 1914, 1918, 1922 and 1930, provide information on birth factors and depression. Women participated from 1968 at mid-life ages of 38-60 years, to 2000, when they were age 78-92 years. Original birth records containing birth weight, length, head circumference, and gestational time, as well as social factors were obtained. Lifetime depression was diagnosed via multiple information sources. Symptoms were assessed using the Comprehensive Psychopathological Rating Scale and diagnoses were based on DSM-III-R criteria. Over their lifetime, 44.6% of women in this sample experienced depression. Birth weights ≤ 3500 g [odds ratio (OR), age-adjusted = 1.72; 95% CI 1.29-2.28, P < 0.001] and shorter gestational time (OR, age-adjusted = 1.13; 95% CI 1.04-1.24, P = 0.005) were independently associated with a higher odds of lifetime depression in a logistic regression model adjusted for age. Lower than median birth weights and shorter gestational time were related to lifetime depression in women. Both neurodevelopmental and environmental contributions to lifetime depression may be considered.