Is stress harmful to an unborn baby? A 2006 study conducted by researchers from the Johns Hopkins University and the National Institute of Child Health and Human Development concludes that mild to moderate maternal stress during pregnancy may actually be beneficial to children.
Contrary to laboratory studies in which induced stress during pregnancy interferes with normal development in animals, the Hopkins study discovered that the children of women who reported modest anxiety and daily stress during pregnancy were more advanced in terms of early child development by age two. Furthermore, maternal stress during pregnancy was unrelated to temperament, attention capacity, the ability to control behavior, or hyperactivity in children.
However, women who regarded their pregnancies as more negative than positive tended to have children with slightly poorer emotional control and attention capacity than women who reviewed their pregnancies as more positive than negative.
Furthermore, the study looked at women who were mostly well-educated, financially stable, and did not have clinically diagnosed psychological problems. Further studies need to be done on women in more disadvantaged situations and women with mental health disorders.
Research also needs to be done to determine whether the findings of this study were a result of biological changes during pregnancy due to stress or whether women who report mild to moderate stress during pregnancy are more likely to engage in behavior that encourages child development.
Mild maternal stress may actually help children mature: http://www.jhsph.edu/publichealthnews/press_releases/2006/dipietro_stress.html
Stressed Woman: http://commons.wikimedia.org/wiki/File:I_Don%27t_Know_ANY_of_This!.jpg