Sex Hormones, Gonad Size, and Metabolic Profile in Adolescent Girls Born Small for Gestational Age with Catch-up Growth

Abstract

Study objective: To characterize and compare sex hormone concentrations, and uterine and ovarian volumes in adolescent girls born small for gestational age (SGA) who had experienced catch-up growth and girls born at a size appropriate for gestational age (AGA), and to investigate the association between these parameters and glucose metabolism, perinatal factors, and early growth.

Design: A prospective, longitudinal, observational study from birth until adolescence.

Setting: Mean age at final assessment was 12.7 ± 0.1 years.

Participants: We followed 55 girls (20 SGA, 35 AGA).

Interventions and main outcome measures: Sex hormone concentrations (gonadotropins, estradiol, testosterone, and sex hormone binding globulin) were analyzed, and the oral glucose tolerance test conducted. Uterine and ovarian sizes were assessed using pelvic ultrasound.

Results: Uterine and ovarian volumes were smaller in SGA-born compared with AGA-born girls (P = .013 and P = .039, respectively). SGA girls had lower sex hormone binding globulin levels (P = .039) and higher testosterone levels (P = .003), free androgen index (P < .001), and glycemia 2 hours post glucose load (P = .005) compared with AGA-born girls. Birth weight and early infancy height velocity explained 37.4% of variation in ovarian volume (P = .004), and body mass index at birth, increase in peripheral skinfold thickness during second year of life, and early childhood height velocity explained 43.2% of variation in testosterone levels in adolescence (P = .006).

Conclusion: SGA-born girls who experienced catch-up growth remain at risk of biochemical hyperandrogenism in adolescence, and have reduced uterine and ovarian volumes, which might influence future reproductive function. Ovarian size and androgen levels in adolescence might be influenced by early growth and subcutaneous fat deposition.

Keywords: AGA; Appropriate for gestational age; Catch-up growth; Gonadal size; Menarche; SGA; Sex hormones; Small for gestational age.