CHICAGO, Dec. 5 (Xinhua) -- U.S. researchers measured the stress hormone cortisol in pregnant women from early pregnancy to when their baby was six weeks old, and found that those with a dissociative type of posttraumatic stress disorder (PTSD) that's often related to childhood abuse or trauma had levels up to 10 times higher than their peers.
These toxic levels of cortisol may contribute to health problems in the next generation.
In the study conducted the researchers at the University of Michigan, 395 women expecting their first child were divided into four groups: those without trauma, those with a trauma but no PTSD, those with classic PTSD and those with dissociative PTSD.
Researchers measured salivary cortisol at different times during the day. Then 111 of those women gave saliva specimens until postpartum.
The difference in cortisol was greatest in early pregnancy, when levels were eight times higher in the afternoon and 10 times higher at bedtime for the dissociative group than for other women.
About 8 percent of pregnant women in the study had PTSD, a disorder that results when symptoms of anxiety and fear persist well after exposure to stressful events. About 14 percent of that group had the more complex dissociative PTSD, which was associated with higher cortisol.
"It's been a mystery in our field why cortisol is sometimes high with PTSD and sometimes not," said Julia Seng, a UM professor of nursing and lead author on the study. "This finding that in pregnancy it's only the dissociative subgroup that has high cortisol gives us more to go on for future research."
Cortisol is sometimes called the stress hormone because it's released in stressful situations as part of the flight-or-fight response. Cortisol levels that stay high are linked to serious health problems such as heart disease and high blood pressure, and can fuel weight gain, depression and anxiety plus a host of other problems.
"We know from research on the developmental origins of health and disease that the baby's first environment in its mother's body has implications for health across the lifespan," Seng said.
"Higher exposure to cortisol may signal the fetus to adapt in ways that help survival, but don't help health and longevity. This finding is very useful because it helps us know which women are most likely to exhibit the highest level of stress and stress hormones during pregnancy and postpartum."
The study has been published in the Journal of Obstetric, Gynecologic and Neonatal Nursing.