Babies whose mothers were very stressed while they were pregnant are more likely to be susceptible to stress themselves, German researchers reported in the journal Translational Psychiatry. This vulnerability to stress is caused by genetic changes that occur in the fetus because of the mother’s stress.

Helen Gunter, PhD, of the University of Konstanz, and team found that adolescents whose mothers suffered domestic violence while pregnant with them had altered expression of a gene associated with behavioral problems and stress response. This alteration in gene expression carries through right into adulthood, the authors believe.

In other words, a receptor for stress hormones seems to change biologically while the baby is still in the womb if the pregnant mother suffers extreme stress, as might occur during intimate partner violence. This change may make it harder for the child to subsequently deal with stress.

This is the first study to associate stress during pregnancy to alterations in DNA methylation – a process which turns genes off and on. It explains how prenatal stressors impact on a person’s mental state throughout their lives.

In this study, involving 25 children aged 10 to 19 years and their mothers, the scientists gathered information on intimate partner violence, among other things. Eight of the mothers had experienced violence during their pregnancies.

The authors explained that the females in this study did not have typical home circumstances – the majority of pregnant women are not exposed to similar persistent levels of stress.

Methylation status of the offspring was analyzed when they were adolescents. Methylation is involved in the regulation of gene expression. They concentrated on the stress-response-mediating glucocorticoid receptor (GR) gene. They found that the fetuses of mothers who were exposed to intimate partner violence during pregnancy had alterations in the methylation of the GR promoter, which indicates poorer ability to deal with stress.

One of the lead researchers, Professor Thomas Elbert, said:

“It would appear that babies who get signals from their mum that they are being born into a dangerous world are faster responders. They have a lower threshold for stress and seem to be more sensitive to it.”

The authors wrote:

“For the first time, we show that methylation status of the GR gene of adolescent children is influenced by their mother’s experience of IPV (intimate partner violence) during pregnancy.”

They added that their findings may have provided a potential mechanism by which prenatal stress could impact on psychological function, through methylation of the GR promoter.

The researchers added that further studies are needed to determine whether these alterations affect children’s coping skills.

The authors concluded:

“As these sustained epigenetic modifications are established in utero, we consider this to be a plausible mechanism by which prenatal stress may program adult psychosocial function.”

“Transgenerational impact of intimate partner violence on methylation in the promoter of the glucocorticoid receptor”
K M Radtke1,2,4, M Ruf1,4, H M Gunter2,3,4, K Dohrmann1, M Schauer1, A Meyer2 and T Elbert
Translational Psychiatry (2011) 1, e21; doi:10.1038/tp.2011.21

Written by Christian Nordqvist