Prenatal testosterone exposure influences language development
MedWire News: Exposure to high levels of bioavailable testosterone in the womb increases the risk for language delay in young boys, but improves language development in young girls, show study results.
"An estimated 12% of toddlers experience significant delays in their language development," said lead author Andrew Whitehouse, from the University of Western Australia in Perth, in a press statement.
"While language development varies between individuals, males tend to develop later and at a slower rate than females."
One mechanism that could explain gender differences in language development could be prenatal exposure to sex steroids such as testosterone, say Whitehouse et al.
To assess the effects of prenatal testosterone exposure on language development, Whitehouse and team collected umbilical cord blood samples at 861 births and analyzed them for bioavailable testosterone.
A total of 767 children (395 male; 372 female) were followed up at age 1, 2, or 3 years, at which points their parents were asked to complete the Infant Monitoring Questionnaire (IMQ) to assess their children's language development. The IMQ measures communication, gross motor, fine motor, adaptive, and personal-social development skills. Overall, 98 children provided data at one time point, 193 children provided information at two of the time points, and 476 at all three time points.
As reported in the Journal of Child Psychology and Psychiatry, significantly more boys had language delay according to the communication section of the IMQ at all three time points than girls. Boys also had significantly lower fine motor and personal-social skills than girls at 3 years of age.
Following adjustment for factors such as maternal age at conception, maternal education, family income, smoking and alcohol intake during pregnancy, and gestational age, boys in the highest quartile for bioavailable testosterone at birth (>0.173 nmol/L) were 2.47-fold more likely to experience language delay in the first 3 years of life than boys in the lowest quartile (<0.087 nmol/L).
However, the opposite was true in girls. Following adjustment for the same sociodemographic and obstetric factors, those in the highest bioavailable testosterone quartile at birth (>0.108 nmol/L) had a 54% reduction in risk for language delay over the first 3 years of life compared with those in the lowest quartile (<0.052 nmol/L).
These results agree with previous studies that have demonstrated a link between language development and the level of testosterone in amniotic fluid.
"Language delay is one of the most common reasons children are taken to a pediatrician," commented Whitehouse. "Now these findings can help us to understand the biological mechanisms that may underpin language delay, as well as language development more generally."
The authors conclude: "At a broader level, this study provides further evidence that umbilical cord blood can provide important data on testosterone and its effect on postnatal development that cannot otherwise be obtained from low-risk pregnancies."
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By Helen Albert