Effects of Socioeconomic Status and Psychosocial Stress on the Development of the Fetus

Recent studies have revealed a relationship between higher levels of maternal psychosocial stress during pregnancy and reduced birth weight and length of gestation. Previously, we have documented poorer fetal neurobehavioral development from mid-gestation in fetuses of healthy women with normal pregnancies who were of low socioeconomic status (SES). 1 Fetuses of low-SES women were found to move less often and with less vigor, display reduced neural integration between cardiac and motor function, and have lower variability in heart rate. Neurobehavioral measures provide information about the nature of the developing nervous system. These data suggest that fetuses of poor but otherwise healthy women with good prenatal care may display indications of developmental immaturity at birth. Although there are many potential mediators of this relationship (e.g., exposure to environmental agents, nutrition), the current analysis was undertaken to determine the role of maternal psychosocial stressors and affect in mediating fetal development. This study included a sample of 103 women with normal pregnancies who were assessed at three gestational ages (24, 30, and 36 weeks), stratified by SES ( n = 52 middle/high SES; n = 51 low SES). The upper SES group consisted of employed, older, well-educated ( M = 16.3 years education) and primarily nonminority (77%) women; subjects in the lower SES group were predominantly unemployed, less educated ( M = 11.8 years), and African American. At each visit, 50 minutes of fetal heart rate and movement data were digitized from an actocardiograph fetal monitor into a computerized analysis system; these data were used to construct measures of neurobehavioral function. Maternal report scales of emotional intensity, daily stressors, and pregnancy-specific hassles and uplifts were administered at each visit. Generalized estimating equation techniques (GEE) were used to model the longitudinal relations between stress and fetal development separately for each SES group. Each equation includes adjustment for maternal education, age, and parity. The de-