Maternal Stress and Fetal/Infant Development

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Recent evidence indicates that the human fetus is exposed to profound influences that have permanent implications for health. Maternal stress initiates a cascade of events that alter normal developmental processes in the human fetus. Human fetuses exposed to elevated stress signals have impaired learning in utero and are at three-fold increased risk for preterm birth and low birth weight. Moreover, as many as one-half of the infants born early or small, have motor, sensory or cognitive handicaps. The primary aim of this five-year proposal is to determine the influence of prenatal maternal stress and maternal neuroendocrine responses on fetal behavior and to assess the relationship between fetal behavior and infant development in a sample of 200 women (one-half Anglo, one-half Hispanic). The specific aims are to: (a) Identify the primary stress factors that influence fetal behavior and (b) infant development. Stress will be measured (interviews and questionnaires) five times during pregnancy. Fetal behavior and development will be quantified by conventional measures of fetal growth and by measures of fetal behavioral state, movement (at rest and challenge), reactivity and habituation of fetal heart rate (FHR). Infant behavior will be assessed with the Bayley scales of Development, the Neuromotor Status Examination and by basal and circadian measures of hypothalamic-pituitary-adrenal (HPA) activity: (c) Determine the influence of maternal stress-related (HPA) axis activity and disregulation on fetal and infant behavior and infant HPA activity. Because maternal stress alters peptide receptors and brain peptide levels in the fetal rat brain and because it influences human fetal behavior and birth outcomes, maternal peptide levels will be assayed from blood obtained at each visit. The influence of maternal stress peptides on infant behavior and HPA activity will be determined at six weeks, six, twelve and twenty-four months. (d) Describe the relationship between fetal behavior and infant outcome. A sensitive measure of fetal CNS activity (habituation) will be integrated with contemporary measures of fetal behavior at rest and after challenge, to describe fetal maturation. These measures will be entered into models to predict infant neuromotor development. This project is designed to identify maternal stressful conditions that are harmful to the fetus by examination of the timing and duration of stress, by investigation of biological mechanisms related to prenatal stress, specifically the HPA and placental axis and by longitudinal studies of developmental consequences of prenatal stress in the infant.