Emma Robertson-Blackmore, Ph.D., has used her 2008 NARSAD Young Investigator Grant to conduct research that adds a new and unexpected dimension to our knowledge about how certain forms of trauma raise the risk that an expectant mother will become depressed. Such depression, of course, can also negatively affect the outcome of the pregnancy as well as the health of the child.
Dr. Robertson-Blackmore (now Research Assistant Professor in the Department of Psychiatry at the University of Florida College of Medicine - Jacksonville), and colleagues at the University of Rochester Medical Center in New York studied 374 women aged 20 to 34, all in the “perinatal” period―beginning about 18 weeks into pregnancy and extending for six months after giving birth. They explain in a paper published in October in the Journal of Clinical Psychiatry that the women were recruited from a low-income inner-city area, and thus were statistically at higher-than-average risk for early-life trauma and depression. Over half the women (52 percent) reported at least one episode of depression prior to entering the study; 39 percent reported at least one early-life traumatic event. Although such traumas can take many forms, the most common in this group were childhood sexual abuse, being exposed to someone who experienced violence, and the unexpected death or illness of someone close.
The main finding was in part surprising. Women exposed in early life to any of the three traumas just mentioned were more likely to get depressed in the pre-childbirth period. However, such depression did not predict that the same women would report depression postpartum. Those who had experienced three or more traumas had four times the prenatal depression risk.
“Why does trauma exposure confer risk in this pattern?” the researchers asked in their paper. They suggest trauma may alter the stress response mechanism, which in turn may make a woman more susceptible to depression during (but not after) pregnancy, owing to hormonal and immune system changes that normally accompany pregnancy. Dr. Robertson-Blackmore and colleagues urge screening for depression during pregnancy as well as early in the postpartum period when depression risk is known to be high. But they also call for identification of a trauma history in high-risk women, which might lead to identification of those women much more likely to get depressed during pregnancy.