Endometrial safety with a low-dose intrauterine levonorgestrel-releasing system after 3 years of estrogen substitution therapy

OBJECTIVE: To evaluate the pharmacodynamic effects of a novel intrauterine drug delivery system, FibroPlant-levonorgestrel (LNG), on the endometrium in 24 postmenopausal women using estrogen substitution therapy (EST) to suppress climacteric symptoms. DESIGN: A 3-year non-comparative prospective clinical trial. SUBJECTS: The treatment with the FibroPlant-LNG intrauterine system (IUS), releasing 14 microg of LNG per day, was part of a regimen for estrogen substitution therapy in symptomatic postmenopausal women to prevent endometrial proliferation and bleeding. The majority of women received percutaneous 17 beta estradiol, 1.5 mg daily, or an equivalent dose by patch or orally, on a continuous basis. OUTCOME MEASURES: Menstrual pattern, endometrial histology and ultrasonographic evidence of endometrial suppression, after 3 years of use. RESULTS: The endometrial histology specimen showed profound endometrial suppression with glandular atrophy and stroma decidualization in all women. On transvaginal ultrasound, this corresponds with a thin endometrium (<5 mm) and clinically with a "bleed-free" menstrual pattern or amenorrhoea. CONCLUSION: The results of this 3-year study in 24 postmenopausal women using EST suggest that the FibroPlant-LNG IUS is effective in causing strong suppression of the endometrium during the entire period of EST. Target delivery in the uterine cavity could be the preferred route of administering a progestin to oppose estrogen stimulation of the endometrium.     

A comparative study of transvaginal uterine ultrasound and endometrial biopsy for evaluating the endometrium of postmenopausal women taking hormone replacement therapy.

OBJECTIVE: Compare transvaginal uterine ultrasound and endometrial biopsy in evaluating the endometrium of postmenopausal women who are taking estrogen replacement therapy (ERT) or hormone replacement therapy (HRT; estrogen and progestin). DESIGN: Prospective multicenter study done in the United States with 148 healthy women with an intact uterus. A total of 121 women used hormonal preparations prescribed by personal physicians. Continuous combined HRT regimens, nonoral forms of ERT or HRT, and intrauterine devices were not allowed for 3 months before the study began. Endometrial biopsy samples were taken within 3 days of transvaginal ultrasound measurement. The uterus was scanned transversely and longitudinally. Endometrial thickness was measured at the thickest part of the longitudinal plane. RESULTS: Endometrial thickness ranged from 1.0 to 25.0 mm. The range in 126 women with a normal endometrium (determined by diagnoses of endometrial biopsies) was 1.0-25.0 mm (median, 5.0 mm); in 15 women with an abnormal endometrium, the range was 2.8-23.0 mm (median, 6.2 mm). A significant difference (p = 0.006) in endometrial thickness was seen between the 38 subjects taking ERT and HRT (median, 6.1 mm) with unexpected bleeding or spotting and the 26 untreated women in the control group (median, 4.0 mm). Overall, results were clinically inconclusive. CONCLUSIONS: Results of ultrasound as a screening technique in postmenopausal women who were taking ERT or HRT did not correlate well with results of endometrial biopsy. Unscheduled bleeding in postmenopausal women should be investigated regardless of results of ultrasonographically determined endometrial thickness. Abnormalities may be found with an endometrial thickness of less than 4 mm with or without HRT and even with no bleeding.     

Hormonal replacement regimens and bleeding

Hormone replacement therapy may increase the quality of life of postmenopausal women. Any regimen need to offer long-term endometrial safety. It is a standard to consider the co-administration of a sequential progestogen when estrogen replacement should be initiated in non-hysterectomized women. It is almost impossible to decide which combination of an estrogen and a progestogen seems to be optimal as individual tolerance of HRT may very well limit acceptability despite metabolic benefits and proven endometrial safety of a given combination. Several combinations of oral and transdermal estradiol or conjugated equine estrogens, oral progestogens, transdermal norethisterone acetate and levonorgestrel, and intrauterine levonorgestrel may achieve endometrial safety. It is noteworthy that there is no uniform correlation between the timing of onset of bleeding induced by any sequential estrogen and progestogen replacement and a certain pattern of histology. Therefore, although it is likely, there is no absolute reassurance that regular bleeding on or after day 11 of progestogen administration rules out abnormal histopathology. Transvaginal sonography seems not to be of pivotal importance to screen asymptomatic women on replacement therapy for detection of serious abnormal endometrial findings such as hyperplasia and endometrial cancer. Continuous combined hormone replacement therapy or the use of tibolone may be an alternative in postmenopausal women, who do not want any uterine bleedings after menopause. However, spottings or bleedings most often occur at the beginning of treatment. Vaginal administration of estriol and estradiol for urogenital symptoms of estrogen deficiency may stimulate the endometrium unintentionally. Available data suggest that use of oral estriol may be associated with endometrial hyperplasia and endometrial carcinoma relatively more often compared to sequential HRT. Raloxifene, a benzothiophene derivative acting as a selective estrogen receptor modulator approved for prevention of vertebral osteoporosis, rarely causes uterine bleeding. There is no ideal therapy available to suit women looking for a permanently bleed-free hormonal replacement therapy today.     

Endometrial bleeding during hormone therapy: the effect of progestogens

Postmenopausal women using continuous combined estrogen/progestin therapy (ccEPT) are likely to have irregular bleeding or spotting. The use of estrogen with 12-14 days of a progestin is called cyclic (scEPT). This method results in regular endometrial bleeding at a scheduled time. The mechanism(s) involved in this regimen that result in bleeding could be similar to a spontaneous menstrual bleeding episode in a menachal woman, but there are no data in this regard. This aspect of regular scheduled bleeding in postmenopausal women will not be addressed in this article due to the paucity of information. The effect of cyclic progestogen with continuous estrogen on the endometrium could result in similar local mechanisms for endometrial bleeding as seen wth ccEPT. The mechanism(s) involved in endometrial bleeding is unknown. Several reports have highlighted a number of potential pathophysiologic mechanisms. Most of the investigation into the mechanisms involved in endometrial bleeding has been in women using progestin only contraceptive methods not ccEPT. The use of ccEPT could be construed as similar but not identical to that of a continuous progestin only contraceptive since the progestin in ccEPT is delivered daily. The potential mechanism(s) involved in endometrial bleeding includes the following: changes in the ratio of vascular endothelial growth factor to Thrombospondin-1 (pro- versus anti-angiogenic factors); alterations in metalloproteinases and tissue inhibitor of metalloproteinases (TIMP); changes in tissue factor a known haemostasis mediator in the endometrium; and increased endometrial leukocytes with a particular emphasis on uterine natural killer (uNK) cells. Each of these potential causes has been the subject of both in vivo and in vitro investigations. There is no clear linkage between any of these hypotheses and the onset or cessation of uterine bleeding in ccEPT users. No good therapeutic option to control the bleeding or spotting exists at this time. Evaluation and monitoring of the patient regarding endometrial safety is of paramount importance.     

Adverse endometrial effects during long cycle hormone replacement therapy

Objectives: treatment with unopposed estrogen is known to increase the risk of endometrial hyperplasia, atypia, and carcinoma, and therefore the administration of a progestin during hormone replacement therapy (HRT) is recommended. The addition of a progestestin may cause unwanted side effects. Progestin administration of various durations are therefore used in HRT. Study design: data were obtained about endometrial histopathology, bleeding interval and compliance in 240 early postmenopausal women receiving HRT with a progestin administered for 10 days during 12 week or 4 week cycles of estrogen administration. These regimens were studied for as long as 4 years. The daily estrogen given was 17β-estradiol 2 mg per day which was reduced to 1 mg day during the last 6 days of each cycle. The progestin used was norethindrone acetate, given at a dose of 1 mg per day. Results: the incidence of endometrial hyperplastic changes, i.e. simple or complex hyperplasia, atypia or cancer, was significantly higher in the 12 weeks cycle than in the monthly cycle group (P=0.003), with an overall annual incidence of 5.6% in the 12 weeks cycle group and 1% in the monthly cycle group. One case of atypical hyperplasia and one case of endometrial adenocarcinoma was observed in the long cycle group. Long cycle treatment produced more irregular bleeding pattern. Accordingly, the rate of drop-out due to bleeding was significantly higher in the long cycle group (P<0.01). Conclusion: we conclude that the long cycle HRT modality investigated did not improve compliance and may increase the risk of endometrial hyperplasia and eventually cancer compared to conventional HRT with a monthly cycle. Caution using long cycle HRT regimens is advisable, and careful monitoring of the endometrium during treatment is recommended.     

Endometrial bleeding in postmenopausal women: with and without hormone therapy

The aim of this study was to present a review of the potential mechanisms involved in the occurrence of endometrial bleeding in postmenopausal women using hormone therapy. Selected literature on the incidence of bleeding in postmenopausal women using estrogen progestogen therapy was reviewed. The incidence of spotting and bleeding in women using continuous-combined hormone therapy was presented. Relevant articles related to the role of angiogenic factors and vasculogenesis in the endometrium, endometrial leukocytes, and endometrial metalloproteinases were used for the review. The cause or etiology of endometrial bleeding with hormone therapy is unknown. Several options are known to alter angiogenesis or be involved in tissue remodeling during normal menstruation. Vascular endothelial growth factor and thrombospondin-1 are proangiogenic and antiangiogenic factors that could cause dysfunction in vasculogenesis that could result in blood vessel fragility and bleeding. The role of pericytes in maintaining vessel morphology and integrity is discussed. Endometrial leukocytes and metalloproteinases are involved in normal menstruation, but their role in postmenopausal bleeding is not clear suggesting involvement of mechanisms in the bleeding. There is limited information on clinical investigation into the etiology of postmenopausal bleeding associated with hormone therapy. The major cause of hormone therapy-related bleeding is unknown. Alterations in angiogenic factors that could result in vascular dysfunction and vessel breakdown provide a working hypothesis as to the potential cause of vessel breakdown.     

The prevention of endometrial cancer in postmenopausal women with progestogens

Due to adverse publicity alleging an increased risk of endometrial cancer with estrogen therapy, a prospective study was begun in 1976 to determine the incidence of this disease in postmenopausal women. During 5,025 patient-years of observation in 1976–1977, 6 adenocarcinomas of the endometrium were diagnosed for an incidence of 1.2: 1,000 postmenopausal women per year. No endometrial malignancies were detected in 2,552 patient-years of therapy with estrogens and progestogens. In 1,028 patient-years of observation where estrogens only was the therapy, there were 3 endometrial cancers for an incidence of 2.9: 1,000. Adenocarcinoma of the endometrium was found in 2 of the untreated group, which gave an incidence of 3.0: 1,000. The sixth endometrial cancer occurred in a patient using estrogen vaginal cream. During this same period, 139 perimenopausal and postmenopausal women were treated with progestogens for endometrial hyperplasia. The hyperplasia was reversed to normal endometrium in 133 patients (95.7%). Hyperplasia is a precancerous lesion and should be treated with either progestogens or hysterectomy. All postmenopausal women with a uterus should be given the Progestogen Challenge Test and the progestogen continued each month as long as bleeding follows. These methods will prevent most endometrial cancers.     

Endometrial response to raloxifene compared with placebo, cyclical hormone replacement therapy, and unopposed estrogen in postmenopausal women.

OBJECTIVE: To determine the endometrial effects of raloxifene 60 mg/day in postmenopausal women as assessed by vaginal bleeding and endometrial thickness. DESIGN: Data from 1157 postmenopausal women were analyzed from a database consisting of four independent, double-blind, randomized, placebo-controlled trials (range = 6-30 months duration), a 24-month open-label randomized, cyclical hormone replacement therapy (HRT)-controlled trial, and a 6-month double-blind, randomized, unopposed estrogen-controlled trial. Vaginal bleeding rate was derived from self-reported adverse events collected at least every 6 months. Endometrial thickness was measured by ultrasonography at regular intervals. RESULTS: Raloxifene 60 mg/day was not significantly different from placebo with regard to the incidence of vaginal bleeding, the baseline-to-endpoint change in endometrial thickness, or the proportion of women experiencing an increase in endometrial thickness above baseline after either 12 or 24 months of therapy. Unexpected bleeding was reported significantly more frequently in the unopposed estrogen groups compared with the raloxifene group (raloxifene 60 mg/day, 0% versus estrogen, 50%; p = 0.002). A significantly greater baseline-to-endpoint increase in endometrial thickness was observed in both the HRT and estrogen groups compared with their respective raloxifene comparison group (raloxifene 60 mg/day, 0.01 +/- 2.0 mm versus HRT, 1.8 +/- 3.2; p < 0.001; raloxifene 60 mg/day, 1.1 +/- 1.7 mm versus estrogen, 7.8 +/- 3.8; p < 0.001). No cases of endometrial hyperplasia or cancer were diagnosed in the placebo or raloxifene 60 mg/day groups. Endometrial hyperplasia was diagnosed in one case in the HRT group and in two cases in the estrogen group. CONCLUSION: Raloxifene 60 mg/day for up to 30 months is not associated with vaginal bleeding or increased endometrial thickness in postmenopausal women.     

雌激素防治骨质疏松症的研究进展

１９４１年Ａｌｂｒｉｇｈｔ首先提出绝经与骨质疏松之间的关系，５０多年来，大量的临床与实验研究证实，雌激素缺乏是绝经后骨质疏松的重要发病因素。低雌激素状态或绝经后补充雌激素，可以预防雌激素低下引起的骨丢失，并对绝经后的多种改变有防治作用，例如绝经后症状...     

Rationale for use of lower estrogen doses for postmenopausal hormone therapy

In placebo-controlled clinical trials low dose estrogens have been shown to reduce hot flashes an average of 65%. Low dosage is effective in preventing bone loss in early menopause and both low and ultralow estrogen dosages can prevent bone loss among women many years beyond menopause. Epidemiological studies indicate less risk of cardiovascular disease and venous thromboembolism in women who use low dose estrogens compared to standard dose. Low dosages of estrogens are less likely to produce unacceptable side effects, such as vaginal bleeding or breast tenderness. When prescribing low dosage estrogen, one can safely use less progestogen, either less daily dosage or less frequent cycles. Older women on ultralow estrogen may not require regular progestogen because the endometrium is not stimulated. In conclusion, there is a strong rationale for use of lower estrogen dosage in HT. Low dosage estrogen can relieve vasomotor symptoms and can prevent postmenopausal bone loss. Women taking low dosages of estrogens are less likely to have unacceptable side effects, such as vaginal bleeding or breast tenderness. Moreover, the potential harm caused by standard dosages of estrogen with progestin, including coronary heart disease, venous thromboembolism, stroke, and breast cancer may be mitigated by use of lower estrogen doses that do not require daily or monthly progestin opposition.     

Endometrial suppression with a new 'frameless' levonorgestrel releasing intrauterine system in perimenopausal and postmenopausal women: a pilot study

OBJECTIVE: A novel intrauterine drug delivery system, FibroPlant-levonorgestrel (LNG), derived from the frameless GyneFix intrauterine device (IUD) is described and the preliminary results in 30 symptomatic climacteric and postmenopausal women are discussed. The treatment with the FibroPlant-LNG intrauterine system (IUS) was instituted to suppress the endometrium during estrogen substitution therapy (EST) to prevent endometrial proliferation and bleeding. The purpose of the study was to evaluate the clinical and ultrasonographic effect of this new intrauterine progestin delivery system. METHODS: Two dosage forms were tested: the first 11 women received a 3-cm long coaxial fibrous delivery system, delivering approximately 10 microg per day of LNG; the remaining 19 women in the study received a 4-cm long delivery system, delivering approximately 14 microg per day. The calculated duration of release of the two systems is approximately 5 years. Twenty-two women were perimenopausal at the start of the treatment. Women in this study were observed for a duration of at least 1 year. Most postmenopausal women received percutaneous 17beta-estradiol (Oestrogel), 1.5 mg daily on a continuous basis. RESULTS: All postmenopausal women in the two groups reported amenorrhea during the entire study period (up to two and a half years follow-up). Endometrial atrophy in these women was confirmed by vaginal ultrasound examination. Seventeen of the 22 perimenopausal women reported amenorrhea at the first or second follow-up visit at 1 and 3 months following insertion of the IUS, respectively. The remaining had infrequent scanty bloody discharge needing a panty liner, at the most, for protection. There were no complications in this study (e.g. infection, expulsion or perforation). The FibroPlant-LNG IUS was very well tolerated by all the women and no systemic hormonal side effects were reported. There were no removals for medical reasons. CONCLUSION: The results of this pilot study suggest that the frameless FibroPlant-LNG IUS is safe, well tolerated and effective in suppressing the endometrium during EST. No differences could be clinically distinguished between the two dosages. Compliance was optimal. The fact that the IUS also acts as a potent contraceptive is of added importance.     

Endometrial effects of three doses of trimegestone,a new orally active progestogen,on the postmenopausal endometrium

Objective: To study the effects of oral trimegestone on endometrial histology and vaginal bleeding when given in combination with oral 17-β-oestradiol. Methods: This was a prospective, randomised, double-blind, parallel groups, pilot comparative study. Thirty-eight healthy postmenopausal women with normal endometrial histology were given oral 17-β-oestradiol, 2 mg/day for three continuous cycles of 28 days, plus oral trimegestone, 0.10, 0.25 or 0.50 mg/day from day 15 to day 28 of each cycle. A Vabra biopsy was performed late in the oestradiol/trimegestone phase of cycle 3 and examined for histological evidence of secretory transformation of the endometrium. Characteristics of vaginal bleeding were recorded on a daily basis. Results: Thirty-seven women completed the study, of whom 31 yielded adequate tissue for histological assessment. All showed secretory transformation of the endometrium. Bleeding was of earlier onset and longer duration with the lowest dose of trimegestone. Conclusions: Trimegestone is a highly effective oral progestogen for endometrial protection, all doses inducing secretory endometrial transformation. Although bleeding patterns suggest a weaker effect of the lowest dose used, the minimum effective dose for endometrial protection has still to be determined and may be lower than those used in this study.     

Management of abnormal genital bleeding in girls and women

Management of abnormal genital bleeding in girls, adolescents and women, in pregnancy, and in postmenopausal women is reviewed under the headings of evaluation and treatment. In childhood all genital bleeding is clinically significant: it is due to acute infection, foreign bodies, trauma, prolapsed urethra or precocious puberty, rarely to tumors. Bleeding in adolescents and adults is most often due to anovulation, usually estrogen-breakthrough bleeding. Other causes are submucosal leiomyomas, cervical or endometrial polyps, lacerations, uterine or cervical cancer, or systemic disorders such as hypothyroidism or bleeding disorders. Evaluation of bleeding in children requires skill and often general anesthesia, especially if peritoneal laceration is suspected. The 1st step in adolescents and adults is to rule out pregnancy. Pap smears are insufficient: biopsies are advised, especially endometrial biopsies in women 40. Hemoglobin, hematocrit and thyroid status, should also be ordered. Specific treatments involve antibiotics for infection, correction of anemia and orthostatic hypotension, reversal of unopposed estrogen, and medical treatment of menorrhagia and dysfunctional bleeding that does not involve hemodynamic instability. Sometimes curettage, endometrial ablation or hysterectomy is needed. Medical management of breakthrough bleeding caused by unopposed estrogen is high dose estrogen followed by progestin therapy to bring about withdrawal, curettage if necessary, then cyclic combined therapy. In young women 4 birth control pills per day for 5-7 days are often prescribed, with cyclic therapy after withdrawal bleeding is obtained. Prostaglandin inhibitors reduce menstrual loss 50%. Endometrial atrophy in post-menopausal women is treated with cyclic conjugated estrogens and then medroxyprogesterone acetate for 10-13 days per month, or continuous combined therapy for those who can tolerate it.     

Changes in the withdrawal bleeding pattern and endometrial histology during 17β-estradiol —dydrogesterone therapy in postmenopausal women: a 2 year prospective study

Objective: To describe changes in the withdrawal bleeding pattern and endometrial histology during a sequential 17β-estradiol —dydrogesterone regimen in postmenopausal women. Design: Open-label, non-comparative, prospective study. Setting: Gynecological outpatient department of a university hospital. Patients: Twenty-seven healthy nonhysterectomized postmenopausal women. Interventions: Continuous micronized 17β-estradiol supplementation, 2 mg daily, and cyclic administration of dydrogesterone, 10 mg daily for the first half of each 28 day treatment cycle. Main Outcome Measures: Changes in the characteristics of the withdrawal bleeding pattern and the endometrial biopsy histology during 2 years of treatment. Results: The initial withdrawal bleeding was comparable to normal menstruation with respect to amount and duration. During the 2 years of treatment the bleeding showed a significant tendency to become shorter with less blood loss. This was mainly the result of the decrease (P < 0.001) in the number of days per cycle with bleeding grade II (normal menstruation). None of the women developed endometrial hyperplasia, and in almost all women the given hormone replacement therapy regimen induced secretory or atrophic changes of the endometrium. Conclusions: This sequential 17β-estradiol —dydrogesterone regimen can be regarded as safe with respect to the prevention of endometrial disease and appeared to foster patient compliance.     

Gynecologic complications of cyclic estrogen progestin therapy

We evaluated the long-term gynecologic risks of postmenopausal estrogen therapy in conjunction with cyclic, monthly progestin (progestin-estrogen replacement therapy, or PERT). Our medical record review showed that incidence of abnormal vaginal bleeding necessitating gynecologic procedures for evaluation was significantly higher (RR, 3.1; 95% CI, 2.1–4.5), as was the rate of endometrial biopsy (RR, 3.4; 95% CI, 2.3–5.1), among women receiving PERT than among women not receiving hormone therapy. We also identified a non-significant trend toward a higher rate of dilation and curettage (RR, 1.5; CI, 0.7-3.3) among women receiving PERT. However, rates of endometrial hyperplasia and hysterectomy were similarly low in both groups. PERT apparently protects women against these serious gynecologic consequences previously seen in women taking unopposed estrogen.     

Can endometrial protection be inferred from the bleeding pattern on combined cyclical hormone replacement therapy

OBJECTIVE: To investigate the relationship between the timing of withdrawal bleeding on hormone replacement therapy and the state of the endometrium. DESIGN: Double-blind, prospectively randomised dose-ranging study. SETTING: Menopause clinics in the UK and the Netherlands. SUBJECTS: Two hundred and seventy one postmenopausal women aged 40-60. INTERVENTIONS: Administration of six 28-day treatment cycles of a continuous daily dose of 2 mg of micronised 17beta oestradiol with a randomly allocated dose of 5-20 mg of dydrogesterone added for the last 14 days of each. METHODS: Comparison of the timing of the withdrawal bleed recorded in subject-held diaries with an endometrial biopsy obtained toward the end of the last cycle. RESULTS: There was a trend towards later withdrawal bleeding with secretory endometrium and earlier bleeding with inactive or atrophic endometrium, but with too much overlap for this to be of clinical relevance. There were two cases of proliferative and one of hyperplastic endometrium, with no characteristic bleeding pattern. CONCLUSION: Combined sequential HRT with progestogen given for 12-14 days very rarely fails to protect the endometrium. Such failures can not be detected by noting the bleeding pattern. The only suspicious pattern is non-cyclic bleeding, but this will not detect every case of hyperplasia or persistent proliferative endometrium.     

Endometrial safety after 5 years of continuous combined transdermal estrogen and intrauterine levonorgestrel delivery for postmenopausal hormone substitution

OBJECTIVE: To investigate endometrial histology and thickness of the endometrium after long-term use of continuous transdermal estrogen substitution combined with intrauterine release of levonorgestrel (LNG) in postmenopausal women. DESIGN: A 5-year non-comparative prospective clinical trial. SUBJECTS: Out of 182 symptomatic postmenopausal women using estrogen substitution therapy (EST) combined with a novel T-shaped LNG-releasing intrauterine system (Femilis Slim LNG-IUS), to prevent endometrial proliferation and bleeding, only those women (n=102) who used two consecutive LNG-IUSs, were isolated with the aim to study the long-term effects on the endometrium. The mean age of the women was 57 years (range 47-71). The majority of women received percutaneous 17beta estradiol, 1.5mg daily, or an equivalent dose by patch or orally, on a continuous basis. MAIN OUTCOME MEASURES: Endometrial histology and ultrasonographic evidence of endometrial suppression, after a period of approximately 5 years of use. The mean duration of use of the regimen was 70 months (range 25-98). RESULTS: The dominant endometrial histologic picture was that of inactive endometrium characterized by glandular atrophy and stroma decidualization (Kurman classification 5b). No cases of endometrial hyperplasia were found. On transvaginal ultrasound, this corresponds with a thin endometrium (< or = 5 mm). CONCLUSION: The results of this 5-year study in 102 postmenopausal women using EST demonstrates that the LNG-IUS effectively opposes the estrogenic effect on the endometrium resulting in strong suppression during the entire period of EST. Due to its high efficacy and absence of systemic effects on organ tissues (e.g., breasts), target delivery in the uterine cavity could be a preferred route to administer a progestagen in women using EST.     

Hormonal pathology of the endometrium.

The endometrial tissue is a sensitive target for steroid sex hormones and is able to modify its structural characteristics with promptness and versatility. This article discusses briefly endogenous hormonal effects (cyclic changes, luteal phase defect, unopposed estrogen effect) and describes the histologic patterns encountered in the most commonly used hormone therapies: oral contraceptives, ovulation stimulation, hormone replacement therapy, and antitumoral hormone therapy. Oral contraceptives exert a predominant progestational effect on the endometrium, inducing an arrest of glandular proliferation, pseudosecretion, and stromal edema followed by decidualized stroma with granulocytes and thin sinusoidal blood vessels. Prolonged use results in progressive endometrial atrophy. Ovulation induction therapy accelerates the maturation of the stroma and is often associated with a discrepancy between early secretory glands and an edematous or decidualized stroma with spiral arterioles. Hormone replacement therapy with estrogen alone may result in continuous endometrial proliferation, hyperplasia, and neoplasia. The use of both estrogen and progesterone elicits a wide range of histologic patterns, seen in various combinations: proliferative and secretory changes, often mixed in the same tissue sample; glandular hyperplasia (in polyps or diffuse) ranging from simple to complex atypical; stromal hyperplasia and/or decidual transformation; epithelial metaplasia (eosinophilic, ciliated, mucinous); and inactive and atrophic endometrium. Progesterone therapy for endometrial hyperplasia and neoplasia induces glandular secretory changes, decidual reaction, and spiral arterioles. Glandular proliferation is usually arrested, but neoplastic changes may persist and coexist with secretory changes. Lupron therapy produces a shrinking of uterine leiomyomas by accelerating their hyaline degeneration, similar to that in postmenopausal involution. It generally produces endometrial atrophy. Tamoxifen for breast carcinoma has an estrogen agonist effect on the uterus in approximately 20% of patients, who develop endometrial polyps, glandular hyperplasia, adenomyosis, and/or leiomyomata. Both endometrioid and nonendometrioid carcinomas are seen, often in polyps. Their causal relationship to tamoxifen therapy is debatable.     

The distribution of endometrial leukocytes and their proliferation markers in trimegestone-treated postmenopausal women compared to the endometrium of the natural cycle: a dose-ranging study.

The effect of trimegestone-based sequential hormone replacement therapy (HRT) on the distribution of endometrial leukocytes and Ki-67 expression was investigated and the findings compared with the endometrium of the natural cycle. Endometrial cells positive for CD45(+), CD56(+), CD3(+), Ki-67(+) and CD45(+)/Ki-67(+) antigens were immunohistochemically evaluated in samples from postmenopausal women who completed a randomized, double-blind, dose-ranging study of oral trimegestone (0.05, 0.1, 0.25 and 0.5 mg per day) from days 15 to 28 with continuous micronized oestradiol 2 mg daily for six treatment cycles. The control samples were luteinizing hormone (LH)-dated endometrial biopsies. Cell counts were interpreted using linear discriminant analysis and unpaired t-test. The dose of trimegestone did not significantly affect the mean count of CD45(+), CD56(+), CD3(+), Ki-67(+) and CD45(+)/Ki-67(+) cells in the endometrial biopsies obtained from treated women. Endometrial sections from women who bled on the day of the biopsy contained higher numbers of CD45(+) and CD56 cells. In the trimegestone-treated endometrium, CD45(+), CD56(+) and CD3(+) cell expression was similar to the proliferative and early secretory phases of the natural cycle. However the expression Ki-67 and CD45(+)/Ki-67(+) cells was similar to the menstrual phase of the natural cycle endometrium. Women treated with four doses of trimegestone exhibited four different bleeding patterns. Therefore the endometrial infiltration with these cells did not explain the pattern of bleeding in women on this HRT regimen.     

Chronic progesterone antagonist-estradiol therapy suppresses breakthrough bleeding and endometrial proliferation in a menopausal macaque model

BACKGROUND: Clinicians routinely prescribe progestins along with estrogens during menopausal hormone therapy (HT) to block estrogen-dependent endometrial proliferation. Breakthrough bleeding (BTB) can negate the utility of this treatment. Because progestin antagonists also inhibit estrogen-dependent endometrial proliferation in women and macaques, we used a menopausal macaque model to determine whether a potent progestin antagonist (ZK 230 211, Schering AG; ZK) combined with estrogen would provide a novel mode of HT. METHOD: Ovariectomized rhesus macaques were treated for 5 months with either estradiol (E(2)) alone, E(2) + progesterone (two doses) or E(2) + ZK (0.01, 0.05 or 0.25 mg/kg). RESULTS: In the E(2) + progesterone groups, progesterone suppressed endometrial proliferation and induced a thick decidualized endometrium. In the E(2) + ZK 230 211 groups, all doses of ZK blocked endometrial proliferation and induced endometrial atrophy. In all ZK-treated groups, the atrophied endometrium contained some dilated glands lined by an inactive, flattened, non-mitotic epithelium. BTB was much lower in the E(2) + ZK groups (17 days of spotting, all groups) than in the E(2) and E(2) + progesterone groups (155 bleeding days, all groups). ZK suppressed E(2) effects in the cervix, but not in the vagina, oviduct or mammary glands. All serum chemistry and lipid profiles were normal. CONCLUSION: The ability of ZK to block estrogen-dependent endometrial proliferation, induce endometrial atrophy and suppress BTB in a menopausal macaque model indicates that progestin antagonists may provide a novel mode of HT.