Continuous combined parenteral estrogen substitution and intrauterine progestogen delivery: the ideal HST combination?

Objective: To evaluate ease of insertion, acceptability and endometrial safety of a novel, miniature intrauterine, T-shaped, levonorgestrel (LNG)-releasing intrauterine system (IUS), Femilis Slim LNG-IUS (Contrel Research, Belgium), combined with parenteral estrogen substitution therapy (EST) in postmenopausal women.
Design: A prospective, non-comparative, study in postmenopausal women. A 3.0 cm long and 2.0 mm wide coaxial fibrous delivery system, delivering approximately 20 microg/day of levonorgestrel (LNG) was used. The drug compartment is provided with crossarms fixed to the upper part of the drug delivery rod. The calculated duration of release of the system is at least 5 years. The majority of women received percutaneous 17beta estradiol (Oestrogel, Besins Int., Belgium), 1.5 mg daily on a continuous basis, which provides sufficient blood levels of estrogen in most women to suppress climacteric symptoms and protection against bone loss.
Primary Outcome Measures: ease of insertion, retention and side effects of the T-LNG Slim IUS.
Secondary Outcome Measures: endometrial safety assessed by transvaginal ultrasound examination and by endometrial biopsy in a subset of women.
Results: One hundred and seventy insertions were performed in postmenopausal women with median age of age 56.6 (range 43.5-80.3). Insertion was easy in 161 (94.2%) and difficult in 9 (5.3%) women. Pain at insertion was rated as none in 57 women (33.5%), mild in 105 (61.7%), moderate in 7 (4.1%) and severe in 1 (0.5%) woman. The system was well retained in the uterus as no expulsions occurred. At the time of study analysis, the total number of women-months was 1797.5. Ninety-five women had the T-LNG-IUS in place for periods in excess of 1 year. The study was well followed-up with lost-to-follow-up rate (defined as no follow-up during 12 months) of zero at the time of study analysis. The number of women continuing the method was 160 (94.1%) including four women which were released from follow-up for various non-medical related reasons. The histological examinations conducted in 105 women showed predominantly inactive endometrium characterized by a pseudo-decidual reaction of the endometrial stroma with endometrial atrophy. The mean thickness (double-layer) of the endometrium was 3.3 mm (range 2-5 mm) which correlated well with the histology results.
Conclusions: The results suggest that the small T-LNG-IUS is easy to insert in most postmenopausal women without anaesthesia and dilatation of the cervix. It is well tolerated, well accepted and effective in suppressing the endometrium during EST. The lack of expulsions of the device in this study is attributed to the optimal design characteristics of the IUS, the absence of uterine bleeding and absent or reduced contractility of the uterus. The study confirms earlier studies conducted with other LNG-releasing systems used for endometrial suppression during EST. The ease of insertion of the small LNG-IUS could be an important incentive to expand the use of the continuous combined regimen with local delivery of the progestogen. It could be a method of choice for endometrial suppression in women using EST with fundamental advantages to systemically applied progestogens which have been the subject of considerable debate as reported in the recent literature.