The role of stress in female reproduction and pregnancy: an update.

Life exists by establishing a balanced equilibrium, called homeostasis, constantly challenged by adverse stimuli, called stressors. In response to these stimuli, a complex neurohormonal reaction exerted by the activation of the so-called stress system is initiated. The latter is activated in a coordinated fashion, leading to behavioral and peripheral changes that improve the ability of the organism to adjust homeostasis and increase its chance for survival.