"Down will come baby": prenatal stress, primitive defenses and gestational dysregulation.

Knowledge of maternal stress and its direct influence on the developing embryo and fetus (prenate) can influence psychotherapeutic treatment decisions, especially when treating patients who are severely traumatized and dissociative. Not only may maternal stress alter prenate neurobiological attachment and stress systems in the limbic-hypothalamus-pituitary-adrenal axis (LHPA) and limbic-autonomic nervous system (L-ANS), but it may also shape the development of prenate 'fixed action patterns' built from primitive defensive reflex activation. As a result, the offspring's defensive, mating and caregiving behavior may all be biased towards survival in a threatening world and may be more readily transmitted to subsequent generations. This theoretical article provides a prenatal relational model that outlines experience- dependent prenate development that is contingent on and concordant with maternal regulation and dysregulation. Not only anxiety, depression and anger, but also posttraumatic stress and dissociation in the mother, may affect the neurobiology of the prenate.