Link between Maternal Stress and Preterm Birth Revealed Unsplash March 11, 2021 Preterm births—births before 37 weeks of pregnancy—are medically labelled ‘idiopathic,’ when they arise from unexplained, spontaneous labor. Preterm births are linked to an array of illnesses and increased risk of death in infancy. Idiopathic preterm birth (iPTB) is linked to maternal depression and post-traumatic stress disorder but the exact molecular mechanism that links maternal stress to preterm birth has been unclear. A new preclinical study conducted at the Morsani College of Medicine Department of Obstetrics and Gynecology, University of South Florida Health (USF Health), has uncovered a mechanism to help explain how psychological or physiological stress in pregnant women triggers iPTB.