BACKGROUND:
Preterm birth and low birthweight contribute substantially to the disproportionately high infant mortality rates experienced by Puerto Ricans in the United States. The purpose of this study was to examine whether the timing and pattern of prenatal psychosocial stress increased risk of adverse birth outcomes in this high-risk population. MATERIALS AND METHODS:
Proyecto Buena Salud was a prospective cohort study conducted from 2006 to 2011 among predominantly Puerto Rican women. Participants (n = 1,267) were interviewed in early, mid-, and late pregnancy. We evaluated associations between early and mid-pregnancy stress (Perceived Stress Scale) and preterm birth and low birthweight, and stress at each pregnancy time point and small for gestational age (SGA). RESULTS:
Elevated levels of perceived stress in mid-pregnancy increased risk for preterm birth and low birthweight in adjusted analyses, with a linear trend observed for each increasing quartile of stress (ptrend = 0.01). Women in the highest quartile of stress experienced three times the risk for preterm birth (odds ratio [OR] = 3.50, confidence interval [95% CI]: 1.38-8.87) and low birthweight (OR = 3.53, 95% CI = 1.27-9.86) compared with women in the lowest quartile. Early pregnancy stress was not associated with preterm birth or low birthweight. Increase in stress from early to late pregnancy increased risk for SGA (OR = 1.90, 95% CI = 1.01-3.59); no associations were found between stress at any timepoint and SGA. CONCLUSION:
Elevated levels of mid-pregnancy perceived stress increased risk for preterm birth and low birthweight, and an increase in stress over the course of pregnancy increased risk for SGA in a population of predominantly Puerto Rican women
