After giving birth, many women experience a week or two of "baby blues," marked by mood swings, feelings of ambivalence toward motherhood, mild depression, and bouts of unexplainable crying. These blues may be a result of hormonal changes; of the way labor, delivery, and motherhood are treated in today's society; or of the isolation new mothers often feel. Certainly lack of sleep plays a role, too.
But in some women -- as many as 11 to 15 percent of new mothers, according various sources -- the baby blues turns into clinical postpartum depression, or PPD. In an even smaller number of women, this can become a major psychological disturbance, called postpartum psychosis.