Endometrial effects of intrauterine levonorgestrel

A review of the endometrial histologic effects of progestins and progesterone receptor modulators in reproductive age women

“…The glands are small and indistinct in more abundant stroma compared to physiologic endometrial atrophy [28]. Norethindrone (NET) 300 mcg/day for a total of 3 months resulted in a variety of endometrial histologic changes occurring irrespective of ovarian function, including proliferative activity, suppressed proliferation, irregular secretion and atrophy [29]. A study of desogestrel 75 mcg/day for a total of 6 weeks showed a spectrum of endometrial changes in biopsies: proliferative endometrium, decidual transformation and glandular atrophy [30].…”

“…4) [29]. Women using the LNG-IUS had endometrial tissue obtained between 3 months and 7 years after insertion.…”

Morphological and Ultrastructural Changes in Human Endometrium Following Low-Dose Levonorgestrel Contraceptive Intrauterine Systems (LNG-IUS-12) 13.5 mg

“…For one thing, an altered cervical mucus from LNG that acts as a barrier to sperm migration, plus the endometrial atrophy that prevents sperm-egg binding were the main mechanism of contraception [3]. For another, the down-regulation of ER and PR in glands and stroma of the endometrium can inhibit cellular proliferation, and embryo implantation can thus be interrupted [4]. Besides, it exerts effects on endometrium that bring some therapeutical benefits.…”

Endometrial progesterone receptors and levonorgestrel as emergency contraceptive

“…A common side effect reported is the unscheduled vaginal bleeding that is associated with atrophic endometrium and disruption of progesterone receptor expression [8].…”