Objectives: To evaluate: (1) the associations between maternal psychological stress, distress and low birth weight (LBW), prematurity and intrauterine growth retardation (IUGR); (2) the interactions between maternal stress, distress and smoking, alcohol and coffee intake; (3) the prevalences of stress and distress in pregnancy.
Design: Longitudinal cohort study.
Setting: Jundiaí city, São Paulo state, Brazil.
Subjects: A total of 865 pregnant women who attended antenatal care between September 1997 and August 2000.
Methods: Measures of stress and distress were obtained, by interview, three times in pregnancy: at a gestational age (GA) lower than 16 weeks, from 20 to 26 weeks and from 30 to 36 weeks. Stress was investigated by the perceived stress scale, PSS, and distress by both the general health questionnaire, GHQ, and the State Trait Anxiety inventories, STAI. The outcomes were: LBW (birth weight <2500 g), prematurity (gestational age (GA) at birth <37 weeks) and IUGR (birth weight for GA <or=10th percentile of William's curve). The associations between the outcomes and the psychological measures were assessed in multiple logistic regression models.
Results: Maternal distress was associated with LBW (RR=1.97, P=0.019) and prematurity (RR=2.32, P=0.015), respectively. There was an interaction between distress and smoking in the second interview (P=0.05). The prevalences of stress and distress in the different interviews of pregnancy varied from 22.1 to 52.9%.
Conclusions: The present study has confirmed that distress is associated with both birthweight and GA. Further research is needed to evaluate the effectiveness of psychological interventions that can improve maternal and foetal well-being.