Racial Disparities in the Association Between Stress and Preterm Birth

Background: High levels of maternal stress have been linked to preterm births. However, findings from previous studies are inconsistent due to the varied use of stress measures. This study examined the effect of maternal stress on preterm birth, using both psychosocial and physiological measures. Methods: This study was conducted among 231 pregnant women enrolled during their first prenatal care visit. Presence of stress was assessed at enrollment using the Perceived Stress Scale (PSS) and Stressful Life Events Inventory (SLEI). Samples of maternal salivary cortisol were obtained during the first trimester and birth outcomes were ascertained at delivery. Multiple logistic regression was conducted to assess the association between stress and preterm birth. Results: The majority of the study participants were Black, not married, less educated and low income. There was an association between cortisol level and preterm birth. Per 1μg/dL increase in cortisol level, the odds of preterm birth increased by 26%. The increase was accentuated in Blacks where a unit increase in cortisol level was associated with higher odds of preterm birth (29%). Conclusions: Stress measures using PSS and SLEI did not reveal a statistically significant association with preterm birth. Health care and public health professionals should be aware of the association between increased cortisol level and preterm birth. Salivary cortisol may be a better predictor of preterm birth than PSS and SLEI.