Pregnancy induces the body to produce a delicate mix of hormones to facilitate fetal development. Doctors have long suspected that stress hormones are strong enough to throw off this balance, based on observations that tragic life events during pregnancy correlate to low birth weight. However, it was not clear what cognitive consequences came with stress-induced low birth weight. Evidence that stress can impair language development appears this month in the Journal of American Academy of Child and Adolescent Psychiatry.
Lead researcher Dr. David Laplante, from the Douglas Hospital Research Centre in Canada, gathered subjects who were pregnant during a massive ice storm that hit Quebec in January of 1998. He had these women fill out questionnaires with both their subjective feelings of stress in the aftermath of the storm and an objective measurement of how many days they had to spend without electricity or in a shelter.
Eighty-nine children resulting from these pregnancies were given a battery of IQ tests at 5.5 years old. Their average score on all language portions was lower in correlation with the amount of time that their mothers spent without electricity or in a shelter. Their performance IQ scores, however, were comparable to those achieved by children born before the storm. This suggests that stress does not cause wholesale brain-damage, but rather alters the development of the brain in anticipation of a harsh environment. It may be that this is an evolutionary strategy where language ability is neglected if the mother’s body senses that the child will be born into a dire situation where words will do little good.
Even if the speculation about adaptive strategies is not confirmed, this study presents strong evidence that stress will change the course of child development. As language is crucial in the modern world, lower verbal IQs can be disastrous. Therefore, mothers should take precautions to avoid stress, and doctors should pay careful attention to pregnancies that have suffered through natural disasters or family tragedies.
