An interesting study was published in the journal Development and Psychopathology that showed they types of stress during pregnancy was less impactful on the baby than the number of stressful events in pregnancy. The more often the mother was stressed, the more likely the

Types of stress included challenges in financial stability, relationship struggles, job losses and difficult pregnancies. Two or fewer stress events was not related to increased childhood behavior challenges, but with more than three stress  there was an incremental increase in behavior issues.

http://www.sciencedaily.com/releases/2011/04/110420111900.htm