Growth and development following prenatal stress exposure in primates: An examination of ontogenetic vulnerability

Previous studies have found that stressful events during pregnancy can infl uence the developing fetus, resulting in attentional and neuromotor problem s. This prospective study examined whether periods of vulnerability exist f or neurobehavioral impairments associated with prenatal stress, using a non human primate model. Twenty-eight rhesus monkey infants were born to mother s in 3 groups: (1) early gestation stress involving mild psychological stre ss from gestational days 45-90, (2) mid-late gestation stress from days 90- 145, and (3) undisturbed controls. Infants were separated from their mother s on days 4, 9, 15, and 22 (+/-1) postpartum for growth and neurobehavioral assessments. Results indicated that infants from the early gestation stres s condition weighed less than infants from mothers stressed during mid-late gestation. Moreover, whereas both groups scored lower than controls on mea sures of attention and neuromotor maturity, early gestation stress was asso ciated with more pronounced and more pervasive motor impairments than mid-l ate gestation stress. These results suggest sensitivity to prenatal stress effects peaks during early gestation, tapering off during mid-late gestatio n. Clarifying the period of greatest vulnerability to prenatal stress moves toward elucidating the underlying mechanism for prenatal stress effects an d may lead to more successful intervention and/or prevention.