Androgen and estrogen secretory dynamics in longitudinally followed moderately and late preterm infant girls

Mini-puberty is a period when the hypothalamic-pituitary-gonadal (HPG) axis is activated and is believed to create the basis for future fertility. In prematurely born females, delayed HPG axis activity and lower reproduction rates have been reported. However, the secretion dynamics of sex steroids in infant girls have not been fully elucidated.

To study sex steroid secretory dynamics in girls born moderately to late preterm during infancy and to find out whether the degree of prematurity or low birth weight may lead to a disturbed sex steroid profile.

From a population-based longitudinal cohort of 70 girls, born at gestational age 32.0 to 36.9 weeks at Sahlgrenska University Hospital, Gothenburg, Sweden, androgen and estrogen concentrations were analyzed during infancy with high-sensitivity mass spectrometry-based methods.

Serum androstenedione and estrone declined continuously during infancy. Testosterone and dihydrotestosterone (DHT) both showed surges around 1 to 2 months chronological age. The surges in estradiol varied individually, with the peak level occurring either before 2 months or at 2 to 3 or 5 to 7 months. At 5 months corrected age, estradiol correlated inversely to gestational age (r = -0.47, P = .000). At 10 months corrected age, gestational age correlated with androstenedione (r = 0.44, P = .002), testosterone (r = 0.32, P = .031), DHT (r = 0.31, P = .043), and estrone (r = 0.43, P = .004).

In girls born moderately to late preterm, DHT, estradiol, and testosterone show a postnatal activity with synchronized surges for DHT and testosterone, while estradiol is secreted with an individual dynamic. Androstenedione and estrone show no surge during infancy. Degree of prematurity but not birth weight influences sex steroid secretion.