Chronic stress in pregnancy: Self-report, biomarkers, and birthoutcomes


Northwestern University

Principal Investigator

Dr. John Thorp, Obstetrics and Gynecology

Project Run Dates

4/1/2011 to 3/31/2013



Chronic stress, with adverse effects on the immune system and on inflammatory response, may be an important cause of preterm birth and associated racial disparities in birth outcomes. However, the association between maternal stress and preterm birth has been inconsistent in the literature. One reason may be the use of multiple and varied measures of stress and the lack of an optimized, validated measure of stress in pregnancy. Using item response theory (IRT) modeling, we propose to develop an optimized self-reported stress measure, derived from the responses of 1,587 women to multiple self-reported stress surveys in the Pregnancy, Infection and Nutrition (PIN) Study database. Specifically, IRT characterizes each item according to its location on the concept’s continuum (ie, stress severity) and its ability to discriminate individuals along this continuum. Having this item-level data will allow us to identify the best items to comprise a more efficient, IRT-optimized stress scale. We propose to use the new stress scale to evaluate the association between stress and CRH and cortisol levels in the women in the PIN Study database. We also will evaluate the association between the new stress measurement tool and adverse pregnancy outcomes (preterm birth and low birth weight) in this population. An IRT-optimized self-report of stress in pregnancy will be an essential bridge to future studies examining associations between self-reported stress, biologic markers of stress and preterm birth. If chronic maternal stress can be shown to be predictive of preterm birth, an optimized measure of stress in pregnancy will allow us to screen high-risk populations and target individual and community level interventions to reduce preterm delivery and, specifically, reduce disparities in preterm birth.