E-Mail COLUMBUS, Ohio - The link between psychological stress and physical health problems generally relates to a stress-induced immune response gone wild, with inflammation then causing damage to other systems in the body. It's a predictable cascade - except in pregnancy, research suggests. Scientists exploring the negative effects of prenatal stress on offspring mental health set out to find the immune cells and microbes in stressed pregnant mice most likely to trigger inflammation in the fetal brain - the source for anxiety and other psychological problems identified in previous research. Instead, the researchers found two simultaneous conditions in response to stress that made them realize just how complex the cross-talk between mom and baby is during gestation: Immune cells in the placenta and uterus were not activated, but significant inflammation was detected in the fetal brain.