Most girls and adolescents with Turner syndrome need oestrogen to complete puberty, because their ovaries do not produce enough of the hormone. The doses used in current practice do not come from large trials but from expert consensus. That lack of evidence leaves an open question: are those doses enough for the uterus to reach a normal size and shape? A team at the Cincinnati Center for Pediatric and Adult Turner Syndrome Care set out to answer it by measuring the uterus of young people who had already reached the adult oestradiol dose.
The study was cross-sectional and included 29 individuals with Turner syndrome and primary ovarian insufficiency, aged 15 to 26, who had reached the adult oestradiol regimen: 100 micrograms transdermally or 2 milligrams orally of 17β-oestradiol. The researchers measured uterine length, volume and the fundal-cervical ratio by imaging, and compared the results with a published sample of 292 age-appropriate controls, aged 15 to 20, without the syndrome. They also reviewed karyotype, breast development on the Tanner scale and laboratory data available in the institutional registry.
The main finding was reassuring, and in some ways unexpected. The authors had hypothesised that uterine size in participants with Turner syndrome would be smaller than in mature females without it. Instead, they found no evidence of compromise in uterine size or configuration. In fact, mean length was 7.7 cm versus 7.2 cm in controls, and mean volume 60.6 cm³ versus 50.5 cm³. Both differences were statistically significant, with p values of 0.03 and 0.02 respectively.
The results suggest that current international doses of 17β-oestradiol, given progressively up to the adult regimen, allow normal uterine growth by the end of pubertal induction. This matters beyond anatomy: a well-developed uterus is a prerequisite for those who may later attempt pregnancy with donor eggs, an option increasingly present in the follow-up of these patients. The authors themselves caution that this is a single-centre study with a small sample and a cross-sectional design, so it cannot establish causality or rule out differences in subgroups by karyotype. Even so, it provides a necessary clinical check on recommendations that until now rested only on expert opinion.
Source: Current Recommended Estrogen Dosing for Pubertal Induction in Turner Syndrome Results in Normal Uterine Growth. Lindsay Mart F, Gutmark-Little I, Streich-Tilles T, Trout AT, Khoury J, Bowers K, Casnellie L, Backeljauw P. The Journal of Clinical Endocrinology & Metabolism 2024;109(3):e1040-e1047. DOI: 10.1210/clinem/dgad649.
