Depression postpartum is a well-recognized phenomenon. However, depression during pregnancy is less well understood. It is defined as the occurrence of depressed moods or loss of interest or pleasure in activities, along with at least four other symptoms during the same two week period. These symptoms may include disturbances in appetite, weight, sleep, motor activity, energy, concentration or the presence of suicidal thoughts and feelings of worthlessness or guilt. An episode of major depression can be categorized as severe, moderate or mild according to the degree to which the affected person's symptoms interfere with social and occupational functioning, including feeding, clothing and maintaining personal hygiene.
Depressive symptoms are usually of less intensity and duration than diagnosable depression.
The boundary between diagnosable depression and depressive symptoms is sometimes unclear. Prevalence estimates of depression during pregnancy varies between 4 and 7.6 percent. The incidence of prenatal depression seems to be increased in the first trimester, suggesting that this is a time of maximum vulnerability to depression. However, depressive symptoms occur in 8 to 38 percent of pregnant women. Sadness is a normal part of life.