NEW YORK (Reuters Health) – The levonorgestrel-releasing intrauterine system (LNG-IUS) is as effective as systemic progestogen regimens for endometrial protection in women taking estrogen replacement therapy for menopausal symptoms.
That finding comes from a meta-analysis conducted by a Thai team, reported in a June 24th online issue of Menopause.
Dr. Woraluk Somboonporn and colleagues at Khon Kaen University note that while progestogen supplementation decreases the risk of endometrial cancer in perimenopausal and postmenopausal women taking estrogen, it has become apparent that systemic progestogen may be associated with adverse effects in other organ systems “particularly an increased risk of cardiovascular diseases and breast cancer.” Therefore, the LNG-IUS, which provides high intrauterine but low systemic levels of levonorgestrel, may be useful in this setting.
To investigate further, the team identified six trials with a follow-up of at least 12 months, in which a total of 518 menopausal women were assigned to undergo estrogen therapy with either the LNG-IUS (20 mcg/day) or a systemically delivered progestogen.
Among the five trials reporting endometrial histology, four found no endometrial proliferation with any type of progestational opposition, and one reported a higher rate with sequential oral medroxyprogesterone acetate. The meta-analysis therefore showed the incidence of proliferative endometrium to be significantly lower with the LNG-IUS than with other systemic progestogens (odds ratio 0.07).
The one trial reporting data on vaginal bleeding showed no difference between the two groups, the investigators found.
Furthermore, the discontinuation rate trended lower (odds ratio 0.62) in the LNG-IUS group than in the systemic progestogen group, according to the report.
However, the longest study was for 24 months, so no conclusions can be drawn about long-term endometrial safety, and none of the studies provided data on breast cancer or cardiovascular disease.
Nonetheless, Dr. Somboonporn and colleagues conclude, “In light of the review, LNG-IUS should be considered as an option for endometrial protection in perimenopausal and postmenopausal women receiving estrogen therapy.”