Prenatal Testosterone Exposure Is Linked to Sexually Dimorphic Changes in Body Composition in 7-Year-Old Children.

CONTEXT: Maternal free testosterone (FT) increases during the third trimester and FT is higher in pregnant women with polycystic ovary syndrome (PCOS) compared to women without PCOS. Higher prenatal androgen exposure has previously been associated with increased catch-up growth in boys.

OBJECTIVE

This work aimed to examine associations between maternal third-trimester testosterone and body composition in boys and girls.

METHODS

This study comprised 1008 mother-child pairs (boys, n = 520) in the Odense Child Cohort (maternal PCOS, n = 101). Maternal FT was calculated from total testosterone (TT) analyzed by mass spectrometry at gestational week 28. Body composition assessments were performed in 7-year-old children by whole-body dual x-ray absorptiometry (DXA, n = 897) measuring body fat (fat mass index [FMI = fat mass(kg)/height(m)2]), percentages of total fat mass, gynoid, and android fat mass) and lean body mass, body weight, body mass index (BMI and BMI z scores), and abdominal circumference. The main outcome was body fat at age 7 years.

RESULTS

In boys, a doubling in FT was associated with a 4.2% increase in FMI (P = .04) and an increase in BMI and BMI z score of 0.2 and 0.1 (P = .05 and .04), respectively. In girls, no statistically significant association was observed between maternal FT and body composition.

CONCLUSION

Boys exposed to higher prenatal levels of FT had higher fat mass, whereas no relation was seen in girls, suggesting a sex-specific susceptibility to prenatal testosterone exposure on child body composition.