Werner,
Elizabeth (9/08) The effects of pregnant women’s mood, stress and cortisol
levels on infant reactivity: a test of fetal programming hypothesis (Gary Kose,
Ph.D.; Paul Ramirez, Ph.D.; Lisa Samstag, Ph.D.)
Of the few studies
that have been designed to better our understanding of the relationship between
maternal prenatal psychological states and the development of infant
temperament style, many are limited by retrospective designs, by parent reports
of child behavior, or by the exclusion of the assessment of maternal HPA axis
hormones, such as cortisol (a possible mechanism through which stress is passed
from the mother to the fetus). Of those studies that have measured maternal
cortisol, baseline levels of maternal cortisol were obtained, but cortisol
reactivity was not. The current study was designed to add to the fetal
programming literature by utilizing a prospective research study that measures
pregnant women's mood, baseline cortisol levels, and cortisol reactivity and
their influence on infant reactivity as measured by standardized laboratory
observation. It was hypothesized that greater degrees of maternal depression,
anxiety, and stress, as well as higher basal cortisol levels and greater
cortisol reactivity will predict more infant motor and crying activity in
response to novelty at 4 months of age. Mother's age and postpartum mood scores
were controlled for in the data analyses. Due to the limited number of
participants in this research, controlling for mother's age in the model often
reduced the significance of the prenatal maternal baseline cortisol variable,
although the relationship between basal cortisol levels and infant reactivity
was largely independent from the relationship between maternal age and infant
reactivity. In an attempt to address this issue and further examine the
influence of maternal cortisol levels on infant reactivity, a subset of the
original sample comprised of women of similar ages (age 20- 29) and their
offspring was examined. In this subset, prenatal maternal baseline cortisol was
a significant predictor ( p = .05) of infant cry reactivity, infant motor
activity (p = .05), and infant reactivity classification (p = .03), with higher
baseline cortisol predicting greater infant reactivity. In addition, it was
also found that less maternal cortisol reactivity during pregnancy was
predictive of greater infant motor reactivity (p = .03) and a greater
likelihood of being categorized as high reactive (p = .04). These results were
the opposite of that proposed in this study's hypotheses. Maternal mood
variables were not found to be a significant predictor of infant reactivity in this
study.
