Mounting evidence indicates that the development of the fetus is heavily
influenced by the intra-uterine milieu during pregnancy, and that such
influence may have life-long consequences for the individual. The intra-
uterine milieu is not only influenced by nutritional factors, but also by
maternal endocrine and autonomic activity. Such activity is prone to be
affected by an individual's personality, but only little is known about
influences of maternal personality on the development of the fetus. We tested
pregnant women for their propensity for impulsive, uncontrollable outbursts of
temper (referred to here as moderate Intermittent Explosive Disorder, mIED).
After the women gave birth, we measured electrocardiograms (ECGs) from their
newborn infants to compare ECGs between newborns of women with and without
mIED. The data show that infants of women with mIED have larger QRS complexes
in the electrocardiogram, and lower heart rate variability, compared to
infants of women without mIED. These results reveal effects of maternal mIED
on the fetal heart development. These effects may predispose the individual to
increased risk for later cardio-vascular disease. The findings open
perspectives for better risk prevention models for the unborn child
