Science Daily has yet more research on the heritability of stress, with research that shows the effects of stress on one pregnant mom can last four generations:
A first generation of rats were subjected to stress late in pregnancy. The following two generations were then split into two groups that were either stressed or not stressed. The daughters of stressed rats had shorter pregnancies than the daughters of those who had not been. Remarkably, the grand-daughters of stressed rats had shorter pregnancies, even if their mothers had not been stressed.
As well as shorter pregnancies, the rats whose grandmothers and mothers experienced stress displayed higher glucose levels than the control group. In addition, rats whose grandmothers or mothers who were stressed weighed less.Gerlinde Metz [of Canada’s University of Lethbridge], senior author of the article, says: “We show that stress across generations becomes powerful enough to shorten pregnancy length in rats and induce hallmark features of human preterm birth. A surprising finding was that mild to moderate stress during pregnancy had a compounding effect across generations. Thus, the effects of stress grew larger with each generation.”