Physiological Mechanisms in Pregnancy and Their Relevance to the Clinical Management of Perinatal Mental Illness.

Perinatal mental illness affects up to 20% of new mothers worldwide, yet despite a growing research interest over the past decade, the etiology is still not fully understood, and clinical treatment guidelines remain inconsistent across countries and services. In this review, recent findings on neurobiological processes and evolutionary mechanisms, as they occur during the menstrual cycle, pregnancy, birth, postpartum and breastfeeding, are discussed. The intention is to raise awareness of physiological changes in pregnancy that might be relevant to the differential diagnosis and clinical treatment of perinatal psychiatric disorders such as depression, anxiety, PTSD after childbirth, bipolar relapse, postpartum psychosis, obsessive-compulsive symptoms, substance-use disorders, and suicidality. Areas addressed include the activities of the immune system, thyroid gland, cortisol, sleep and individual sensitivity to ovarian hormone fluctuations. Evolutionary biological mechanisms intended to sustain pregnancy and to ensure the survival of the newborn are assumed to have potent effects on the maternal brain. These non-pathological adaptations could provide grounds for a better understanding of risk factors and the etiology of perinatal mental illness.