The Western Australia Pregnancy Cohort Study was designed to test effects of particular kinds of maternal stress events during pregnancy on subsequent behavioral problems of the offspring. Robinson et al. (2011) reported prediction of children’s CBCL scores at ages 2, 5, 8, 10, and 14 years from several kinds of independent stress events (events beyond the mother’s control) and dependent stress events (events at least partly within the mother’s control) reported at 18 and 34 weeks gestation. The independent events included deaths of relatives and friends, nonvoluntary loss of jobs by mothers or partners, and pregnancy problems. The dependent events included separation, divorce, residential moves, marital problems, problems with children, and money problems.
After controlling for other risk factors, Robinson et al. found that children whose mothers experienced at least three stress events had significantly (p<.001) higher CBCL Total Problems scores at all ages than children whose mothers experienced fewer than three stress events. The number of stress events also predicted significant elevations of CBCL Internalizing and Externalizing scores. Effects were similar for independent and dependent events and for reports at 18 weeks and 34 weeks. Because children’s CBCL problem scores increased with the number of prenatal stress events, Robinson et al. concluded that “Our results concerning the relationship between the number of stressful events in pregnancy and behavioral impact on the child support a linear dose-response relationship” (p. 514).
Reference: Robinson, M., Mattes, E., Oddy, W.H., Pennell, C.E., Van Eekelen, A., McLean, N.J., Jacoby, P., Li, J., DeKlerk, N.H., Zubrick, S.R., Stanley, J., & Newnham, J.P. (2011). Prenatal stress and risk of behavioral morbidity from age 2 to 14 years: The influence of the number, type, and timing of stressful life events. Development and Psychopathology, 23, 507-520.