Is There a Difference between Ultrasonographic (US) Uterine Changes of Oral Versus Transdermal (TD) 17β Estradiol (17β E2) in Girls with Turner Syndrome (TS)? Own Experience and Literature Review.

Background: Among patients with Turner Syndrome (TS), premature ovarian failure is a main feature. Recently published consensus guidelines recommend that transdermal (TD) estradiol is the preferred route for estrogen replacement. Studies related to ultrasound (US) measurements during estrogen replacement in TS patients using estradiol (17β E2) and correlating uterine growth with estrogen metabolites are limited.

Objectives: To compare uterine morphology and hormonal changes depending on route of administration of 17β E2 (oral vs. TD) in a small population of girls with TS.

Subjects: 11 hypogonadal girls with TS (mean (SE) age 14.5 ± 1.4 years; BMI -0.98 ± -1.0 SDS) who participated in a larger study on the effects of oral versus TD 17β E2 agreed to do a sub-study on the effect of the form of 17β E2 treatment on uterine size.

Methods: 17β E2 was given orally or TD for 12 months, titrated to doses up to 2 mg orally or 100 μg TD to achieve normal estradiol levels. Subjects received monthly progesterone for 1 week for withdrawal bleeding. At baseline, 6 and 12 months, a pelvic ultrasound was performed while on estradiol only.

Results: Uterine morphology and endometrial thickness increased comparably in both groups. E2 concentrations were comparable at 12 months between both groups but E1 and E1S were lower in TD group at 12 months.

Conclusions: According to our experience, in a group of TS patients randomized to oral vs TD 17β E2 and monitored with trans-abdominal US, both groups achieved similar increases in uterine size comparable to normal women. To confirm our observation a larger sample and a longer evaluation period is needed.