Cumulative or chronic environmental stress and high scores on psychopathology scales have been consistently linked to preterm labor. In the laboratory, psychological stimuli have also been shown to affect uterine activity. Clinical studies suggest that interventions which reduce tension and anxiety can prevent or inhibit preterm labor. A model is proposed that links preterm labor to a disorder of arousal manifested physiologically as a hyperreactivity of the limbic circuitry and its efferent components. Autonomic hyperreactivity has been found repeatedly in women who experience preterm labor. This central hyperreactivity could unleash a cascade of psychophysiological reactions that could cause uterine excitation and facilitate preterm labor.