SUN-177 Pubertal timing and height gain during GH therapy in short children born small for gestational age treated before puberty : a Belux GH registry study

Abstract Disclosure: J. De Schepper: None. M. Thomas: None. E. Nauwynck: None. M. den Brinker: None. H. Dotremont: None. C. Heinrichs: None. P. Lysy: None. A.M. Rochtus: None. S. Vanderstraaten: None. K. Huysentruyt: None. D. Beckers: None. M. Becker: None. Background. The few studies on pubertal development and growth in short small for gestational age (SGA) children during growth hormone (GH) therapy have reported controversial data. The objective of this retrospective study is to assess pubertal onset, pubertal height gain, menarche (M) and testes volumes (TV) in a large cohort of short SGA children who started GH therapy before puberty.Methods. In the Belux GH registry data on pubertal development and growth were analyzed in 182 short (height SDS < -2.5 and > 1 SDS below mid-parental height) SGA (birth weight and/or length SDS for gestational age < - 2 ) children, who started GH therapy before puberty and had obtained near adult height.Results. A start of GH therapy, median (Q1;Q4) age in females (n= 82) and males (n = 100) (8.8 (6.3; 10.8 ) vs 9.0 (6.6;11.6) years; p=0.188) and height SDS (-3.01 (-3.45;-2.75) vs -2.99 (-3.4;-2.76); p=0.614 ) were similar. 16 girls and 20 boys entered in puberty during the first year of GH therapy and 13 males and 4 females after more than 7 year of therapy. Mean (SD) age at onset of puberty was 1 year earlier in girls (11.7(1.5) vs (12.7(1.21) years; p< 0.001), while pubertal treatment duration was longer in boys (3.8(0.9) vs (3.4(0.7) years ; p=0.001). Absolute mean pubertal height gain was greater in males (25.0 (6.2) vs (18.1 (5.5)cm; p<0.001), while relative height gain SDS was similar ( 0.31(0.65) vs 0.31(0.80); p=0.944). Menarche occurred at a mean age of 13.9 (1.14) years or 2.2 (0.79) years after Tanner B2 stage (missing data in 4 females). At stop of GH therapy (median age : 16.5 (15.9;17.1) years) median left and right TV of 61 adolescents with available measurements was 15 (12;20)ml and 18 (12;20)ml. 10 males had a TV below the reference limit for age. Mean TV correlated positively with height SDS (p = 0.0019) and BMI SDS ( p=0.04) at examination and pubertal absolute height gain (p < 0.001). Pubertal height gain SDS correlated (p<0.001) positively with birthweight SDS and age at start of GH therapy and onset of puberty and negatively with prepubertal height gain SDS and age and height SDS at start of puberty. Age at onset of puberty and age at menarche correlated (p<0.001) negatively with height SDS at start of therapy, but positively with age at start of therapy, while the time interval between B2 and M was negatively correlated with age at start of puberty (p=0.001). Age of pubertal onset in males and females was later (p <0.0001) than in the Belgian reference population: respectively 1.3 years and 1 year. Menarche was delayed with 0.7 years. Conclusion. In Belgian GH treated prepubertal short SGA children, onset of puberty and age of menarche were slightly delayed, while a normal chronology of menarche was observed. Older age and greater height deficit at start of GH therapy are associated with a later pubertal onset, while a lower birth weight and a younger age at start of GH therapy and a greater prepubertal height gain limit the pubertal height gain. Presentation: Sunday, July 13, 2025