Minipuberty in born small for gestational age infants: A case control prospective pilot study

Abstract

Purpose: To evaluate minipuberty (MP) in small for gestational age (SGA) infants, both preterm and full-term, during the first year of life.

Methods: 33 SGA healthy newborns (group A), 21 of which full-term (subgroup A1) and 12 preterm (A2) were enrolled. Control group (B) consisted of 27 AGA, 17 full-term (subgroup B1) and 10 preterm (B2) infants. Growth parameters, FSH, LH, and Estradiol (E2) or Testosterone (T) serum levels were monitored at 3, 6, and 12 months.

Results: The gonadotropin surge reached greater increase of LH in males at 3 months and FSH in females at 3, 6 and 12 months (p < 0.001). In male infants: T at 3 months was higher in subgroup A2 vs A1(p = 0.001), and correlated negatively with gestational age (GA, p < 0.005), length and weight at birth (p < 0.05); LH was higher in subgroup B2 vs B1 at 6 months (p = 0.003), and in group A vs B at 12 months (p = 0.03). Females displayed higher E2 at 6 months in B2 vs B1 (p < 0.05), negatively correlated with GA and weight gain (p < 0.05); LH at 6 months was increased in A2 vs A1 (p = 0.03). Overall, preterm males displayed higher T at 3 months (p = 0.001), LH at 3, 6 and 12 months (p < 0.05), and LH/FSH ratio at 6 months (p = 0.001). Preterm females exhibited increased LH/FSH ratio at 3 and 6 months (p < 0.05).

Conclusions: Irrespectively of GA, MP occurred with a typical sexual dimorphism and exhibited sex-specific correlations between hormones and perinatal parameters. SGA condition and prematurity seemed to enhance and protract MP over time in both sexes.

Keywords: Gonadotropins; Hypothalamo-pituitary-gonadal axis; Minipuberty; Preterm infant; Small for gestational age.