Testicular Volume of 4 mL Is Not an Appropriate Marker of Pubertal Onset in a Subset of Boys Born Small for Gestational Age.

Abstract

Introduction: Considering that testicular volume (TV) is probably not an adequate marker of pubertal onset in boys born small for gestational age (SGA), we aimed to describe the progression of pubertal clinical and biochemical characteristics, comparing the trajectory of TV with other parameters as markers of pubertal onset in boys born SGA.

Methods: We performed a retrospective, descriptive study of a cohort of boys born SGA with longitudinal follow-up. We determined the TV at the time when serum AMH decreased ≥30% or LH attained 0.35 IU/L.

Results: Thirty boys born SGA were included: 16 of 30 (53.3%) had LH ≥0.35 IU/L and 7 of 24 boys (29.2%) had a decline ≥30% in serum AMH with a TV <4 mL. LH ≥0.35 IU/L and AMH decrease ≥30% were observed at least 1 year before TV 4-5 mL in 11 of 22 (50%) and 3 of 19 (15.8%) boys, respectively. During follow-up, higher serum LH, FSH, and testosterone and lower AMH levels than those expected for TV were observed, indicating that some boys born SGA have a more advanced stage of puberty than their TV suggests.

Conclusion: We identified a subgroup of boys born SGA in whom hormonal changes typical of initial puberty (serum LH ≥0.35 IU/L and AMH decline ≥30%) occurred before a clinical diagnosis of pubertal onset (TV ≥4 mL) was evident. These results indicate that TV 4 mL is not a reliable clinical sign of pubertal onset in all boys born SGA and that other biomarkers, such as serum LH and AMH, may need to be assessed.