Objective: We examined the impact of chronic stress on the relationship between second-trimester serum corticotropin releasing hormone (CRH) concentrations and preterm delivery (PTD) in working women.
Methods: Birth records from mothers of 364 PTD and 730 controls in Southern California were linked to stored mid-pregnancy maternal serum analysed for CRH. Association of CRH with stressors reported in post-partum interviews was examined in cases and controls separately. Stratified multivariable logistic regression analyses examined moderating influence of seven chronic stressors on CRH in predicting PTD.
Results: Mean log CRH was lower among women with chronic stressors. Chronic stressors were not related to an increased risk of PTD, but did strengthen the association of CRH with PTD. Adjusted for confounders, the odds of PTD were 1.5-times higher per unit increase in log CRH in the overall study population, but were two-to-three times higher in subjects who reported unfulfilling jobs, little sleep or strong anger in the second trimester.
Conclusion: The relation of CRH with PTD is moderated by exposure to chronic stressors during pregnancy.