Free testosterone levels in umbilical-cord blood predict infant head circumference in females

Abstract

Aim: Fetal androgens influence fetal growth as well as postnatal neurocognitive ability. However, to our knowledge, no published study has prospectively examined the impact of early-life androgens on infant brain growth. We report the association between circulating fetal androgen levels, measured from umbilical-cord blood at birth, and a proxy measure of brain growth: head circumference. Method: Participants were 82 unselected female infants from a large representative birth cohort (mean gestational age 39.4wks, SD 1.7). Umbilical-cord blood was obtained at birth and analysed for androgen concentrations (total testosterone, androstenedione, dehyrdroepiandrosterone, and its sulphated metabolite). Head circumference and two other measures of growth - weight (mean 3311.4g, SD 461.3) and length - were measured within 3 days of birth and again at approximately 1 year of age (mean age 13.1mo, SD 1.1). Results: Multivariate linear regressions found an inverse association between levels of free testosterone and growth in head circumference (correlatio n=-24), even when adjusting for sociodemographic/obstetric covariates and head size at birth. Growth in weight and length could not be predicted by free testosterone concentration. Interpretation: This is the first report of an association between prenatal androgen levels and postnatal growth in head circumference. These findings suggest that early-life androgens may impact brain development during infancy. © The Authors. Journal compilation © Mac Keith Press 2009.