Longitudinal Sex Steroid Data in Relation to Birth Weight in Preterm Boys

Abstract

Context There is a lack of knowledge on longitudinal sex steroid patterns during infancy, especially for boys born preterm, or with low birth weight (LBW). Objective To find out whether LBW boys have a disturbed sex steroid profile during infancy. Design and setting Population-based longitudinal study performed at Sahlgrenska University Hospital, Gothenburg, Sweden. Participants Ninety-eight singleton boys (47 LBW) born at gestational age 32.0 to 36.9 weeks were included. Due to dropout, eighty-three of the boys were still in the study at 10 months corrected age. Main outcome measures Serum androgen and estrogen concentrations were analyzed by gas chromatography-tandem mass spectrometry and IGF-I was determined with radioimmunoassay in umbilical cord and at 0, 2, 5, and 10 months corrected age. Results Serum levels of androstenedione, estrone, and estradiol declined gradually from birth to 10 months corrected age. In both LBW boys and their counterparts, a surge was seen at 2 months corrected age (3 months chronological age) for testosterone, median (range) 6.5 (2.0 – 18.9) nmol/L, and in dihydrotestosterone 1.2 (0.4 – 4.3) nmol/L. At birth, LBW boys had higher median testosterone (0.7 versus 0.4 nmol/L, p=0.019), and at 0 months corrected age, both higher testosterone (5.7 versus 3.5 nmol/L, p=0.003) and dihydrotestosterone (1.2 versus 0.9 nmol/L, p=0.006) than their counterparts. At 10 months corrected age, catch-up in weight SDS from birth correlated with testosterone (rho=0.27, p=0.044), and androstenedione (rho=0.29, p=0.027). Conclusions Moderately to late preterm LBW boys showed a disturbed sex hormone profile, with elevated concentrations of androgens in early infancy.