Endocrine Abstracts

Background: Maternal free testosterone (FT) increases during 3rd trimester pregnancy and FT levels are higher in women with polycystic ovary syndrome (PCOS) compared to controls. Fetal exposure to maternal FT during 3rd trimester was associated with lower weight, length and shorter abdominal circumference at birth, in boys. Furthermore, lower birth weight has been related to higher abdominal fat mass in young children.

Aim: To examine associations between maternal 3rd trimester testosterone exposure and body composition in children born of women with and without PCOS using whole body dual X-ray absorptiometry (DXA), and to consider the importance of offspring sex.

Hypothesis: Higher prenatal testosterone exposure associates with more fat mass in young children and boys are more susceptible than girls.

Methods: The study is part of the prospective Odense Child Cohort comprising 1,486 mother-child dyads, with a PCOS diagnosis in 145 (9.8 %) women. Exposure: Maternal testosterone at gestational week 28; FT was calculated from total testosterone (TT), analyzed by mass spectrometry. Outcome: Body composition of 1,008 children (520 boys) at 7 years-of-age (7.0-7.6 years) measured by DXA (lean body, fat, gynoid- and android fat percentage, fat mass index and fat free mass index) and clinical examination (weight, height, body mass index (BMI), abdominal- and head circumferences). Multiple linear regression models were adjusted for maternal age, parity and birth weight.

Results: Maternal FT and TT were comparable in women carrying a boy or a girl. At age 7 years, boys were significantly higher (126.6 vs 125.5 cm, P<0.001) and abdominal circumference was longer (56.5 vs 55.6 cm, P<0.001) compared to girls. In boys, a doubling in FT and TT were associated with an increase in weight of 0.53 kg (P=0.01) and 0.47 kg (P=0.05), respectively and a doubling in FT was associated with an increase in BMI z-scores of 0.16 (P=0.01) and a 4.4 % increase in fat mass index (P=0.03). A maternal PCOS diagnosis tended to be associated with a lower gynoid fat percentage of 1.8 % (P=0.07) in girls.

Conclusion: Prenatal exposure to higher FT was linked to larger weight and fat mass index in boys at 7 years. Our data supported an increased susceptibility to prenatal testosterone exposure in boys compared to girls, which may increase future metabolic risk. Furthermore, gynoid fat percentage tended to be lower in girls of women with PCOS compared to controls.