(IsraelNN.com) A new Israeli study shows that stress during the nine months of pregnancy can lead to slower development, learning and attention difficulties, anxiety, depressive symptoms, and possibly even autism in a child. Israeli researcher Professor Marta Weinstock-Rosin of the Hebrew University of Jerusalem was able to demonstrate conclusively that there is a definite link between mother's stress and child harm, according to a report by Israel 21c. 

Working with a team of researchers, Weinstock-Rosen, from the Hebrew University's School of Pharmacy, was able to compare the behavior of the offspring of stressed rat mothers with those whose mothers were not stressed. The research also compared the results of administering various types of stress at different periods during the gestation process to see which period is the most sensitive.

Impaired abilities
The laboratory results showed that when mothers were subjected to stressful situations such as irritating sounds at alternating times, their offspring were later shown to have impaired learning and memory abilities, less capacity to cope with adverse situations (such as food deprivation), and showed symptoms of anxiety and depressive-like behavior.

Dr. Weinstock-Rosen claims that these symptoms are similar to impairments observed in children born to human mothers who were stressed in pregnancy. However, the rats in control groups who were born to unstressed mothers did not manifest these problems.

Cortisol - the culprit?
Theories relating developmental and emotional problems to stress have circulated for some time. However, objective measurement has so far been elusive in humans since evidence is largely anecdotal and is strongly influenced by genetics and other factors.

The chemical culprit behind stress damage may the hormone cortisol that is released by the adrenal gland during stress and reaches the fetal brain during critical stages of brain development.

Under normal conditions, cortisol reaches the brain in small amounts and for a short period of time and has the beneficial role of supplying instant energy. However, under conditions of stress, a large amount of this hormone can reach the fetal brain and can cause structural and functional changes.

Weinstock-Rosen's research along with the work of colleagues from Israel, the UK and elsewhere, will be presented at an international conference called "Long Term Consequences of Early Life Stress," in Jerusalem in October 2009.