Oral Hormone Replacement Therapy and Uterine Volume in Korean Adolescents with Turner Syndrome: A Retrospective Case-Control Study

Study Objective: We aimed to identify critical factors for uterine development by comparing uterine volume (UV) among patients with Turner syndrome (TS) who underwent pubertal induction (PI), patients with TS who had natural menarche (NM), and patients in a non-TS control group. Methods: This retrospective case-control study included patients with TS who had undergone PI with oral estrogen in a PI group ( n = 31) and an NM group ( n = 7). The control group included patients without TS with spontaneous puberty who underwent pelvic ultrasound at 16 years of age. For TS patients, both the UV from the first ultrasound performed at age 16 or older (1st-UV) and the UV from the most recent final ultrasound (final-UV) were obtained. Results: The 1st-UV was larger for patients in the NM group than those in the PI group ( P < .001), but did not differ significantly between the NM and control groups ( P = .375). The final-UV of the PI group was larger than their 1st-UV ( P < .001), but still smaller than the NM group ( P = .021). Hormone replacement therapy (HRT) duration and 1st-UV of PI group were positively correlated ( P = .048). There were no variables that were significantly correlated with final-UV of PI group. Conclusion: Patients with TS who experienced NM showed normal uterine development, but TS patients who underwent PI showed significantly smaller, undeveloped UV. While HRT duration and UV are positively correlated at the beginning of HRT, it is unclear what determines the final UV; however, late PI initiation and use of oral estrogen probably contributed to the lack of UV development.