Although history records that women have suffered from PPD for centuries, little attention is directed to this serious disorder in today's medical and legal communities. Medical research indicates that PPD is the result of the physical stress of pregnancy and childbirth, the social stress of the mothering role, or a combination of both. PPD has four phases: maternity blues, postnatal exhaustion, postnatal depression, and puerperal psychosis. Victims of puerperal psychosis manifest bizarre behaviors, including the murder of their own children. Approximately 18 cases in the United States have involved the use of PPD as a defense to murder. British medical and legal authorities recognize PPD as a serious women's health issue and as a viable insanity defense. Legal experts in the United States believe that the PPD defense will be used more frequently in this country in the future, and the legal and medical analysis supports the appropriateness of this conclusion. 16 references (Author abstract modified)