Efficacy and safety of ultra-low-dose estradiol and norethisterone in postmenopausal Brazilian women.

OBJECTIVE: This study aimed to evaluate the efficacy and safety of oral ultra-low-dose continuous combination of 17ß-estradiol (17ß-E2) and norethisterone acetate (NETA) in postmenopausal Brazilian women. METHODS: Postmenopausal women (age 45-60 years) with amenorrhea >12 months and intact uterus, with moderate to severe vasomotor symptoms, were included. The vasomotor symptoms and endometrial bleeding were evaluated by a daily diary for 24 weeks, and the women were assessed at baseline and endpoint. RESULTS: A total of 118 women were included. The group treated with 0.5 mg 17ß-E2/0.1 mg NETA (n = 58) showed a percentage reduction of 77.1% in the frequency of vasomotor symptoms versus 49.9% in the placebo group (n = 60) (p = 0.0001). The severity score showed a reduction in the treatment group when compared to the placebo (p < 0.0001). The adverse events were comparable between the groups; however, in the 0.5 mg 17ß-E2/0.1 mg NETA group there were more complaints of vaginal bleeding; despite that, in most cycles in both treatment groups, more than 80% of women experienced amenorrhea. CONCLUSIONS: The combination of 0.5 mg 17ß-E2/0.1 mg NETA in a continuous combination regimen was shown to be effective in reducing the frequency and severity of vasomotor symptoms in Brazilian postmenopausal women.

Effects of ultra-low dose hormone therapy on biochemical bone turnover markers in postmenopausal women: A randomized, placebo-controlled, double-blind trial.

OBJECTIVE: Evaluate the effects of ultra-low-dose hormone therapy (Ultra-LD HT) with 17ß-estradiol 0.5 mg and norethisterone acetate 0.1 mg (E2 0.5/NETA 0.1) versus placebo on bone turnover markers (BTM) in postmenopausal women. STUDY DESIGN: A multicenter, double-blind, randomized, placebo-controlled study was performed with 107 participants who received one tablet daily of E2 0.5/NETA 0.1 or placebo for 24-weeks. Bone formation markers-N-terminal propeptide of type I procollagen (PINP) and Bone-specific alkaline phosphatase (BSAP), and bone resorption markers-C-telopeptide of type I collagen (CTX-I) and N-telopeptide crosslinked of type I collagen (NTX) were assessed before and at 12 and 24-weeks of treatment. RESULTS: Women treated with E2 0.5/NETA 0.1 had a significant reduction in the PINP marker from baseline (58.49 ± 21.12 µg/L) to week 12 (48.31 ± 20.99 µg/L) and week 24 (39.16 ± 16.50 µg/L). Placebo group, the PINP marker did not differ significantly. The analysis of the BSAP indicated a significant increase in the placebo group (13.8 ± 5.09 µg/L and 16.29 ± 4.3 µg/L, at baseline and week 24, respectively), whereas in the treatment group the values did not change. The analysis of the NTX marker showed a significant reduction only in the treatment group (43.21 ± 15.26 nM/mM and 33.89 ± 14.9 nM/mM, at baseline and week 24, respectively). CTX-I had a significant decrease in the treatment group from baseline (0.3 ± 0.16 ng/L) to week 12 (0.21 ± 0.14 ng/L) and week 24 (0.21 ± 0.12 ng/L). CONCLUSION: Women receiving E2 0.5/NETA 0.1 experienced reductions in bone resorption and formation markers, an expected effect during the anti-resorptive therapy, suggesting a protective bone effect with the Ultra-LD HT.

What is the influence of hormone therapy on homocysteine and crp levels in postmenopausal women?

OBJECTIVE: To evaluate the influence of estrogen therapy and estrogen-progestin therapy on homocysteine and C-reactive protein levels in postmenopausal women. METHODS: In total, 99 postmenopausal women were included in this double-blind, randomized clinical trial and divided into three groups: Group A used estrogen therapy alone (2.0 mg of 17ß-estradiol), Group B received estrogen-progestin therapy (2.0 mg of 17 ß-estradiol +1.0 mg of norethisterone acetate) and Group C received a placebo (control). The length of treatment was six months. Serum measurements of homocysteine and C-reactive protein were carried out prior to the onset of treatment and following six months of therapy. RESULTS: After six months of treatment, there was a 20.7% reduction in homocysteine levels and a 100.5% increase in C-reactive protein levels in the group of women who used estrogen therapy. With respect to the estrogen-progestin group, there was a 12.2% decrease in homocysteine levels and a 93.5% increase in C-reactive protein levels. CONCLUSION: Our data suggested that hormone therapy (unopposed estrogen or estrogen associated with progestin) may have a positive influence on decreasing cardiovascular risk due to a significant reduction in homocysteine levels.

Effects of a continuous-combined regimen of low-dose hormone therapy (oestradiol and norethindrone acetate) and tibolone on the quality of life in symptomatic postmenopausal women: a double-blind, randomised study.

OBJECTIVE: This study compared the effects of a continuous-combined regimen of low-dose hormone therapy (LD-HT) versus tibolone and supplemental calcium/vitamin D3 (control) on quality of life (QoL) in symptomatic postmenopausal women. DESIGN: This study was a prospective, randomised, double-blind, comparative trial with a control group. SETTING: The study was conducted in a climacteric outpatient clinic in the University Hospital of Federal University of Juiz de Fora, Brazil. POPULATION: A total of 174 postmenopausal women under 60 years of age who attended the climacteric outpatient clinic between June 2009 and June 2011 were recruited. These women complained of moderate or intense vasomotor symptoms and exhibited no contraindications for the use of hormone therapy. INTERVENTIONS: The patients were randomised into three groups: (1) daily treatment with 2.5mg tibolone (n=64), (2) 50mg calcium carbonate+200 IU vitamin D3 (Ca/Vit D3, n=54) or (3) 1mg oestradiol+0.5mg norethindrone acetate (E2/NETA, n=56) for 12 weeks. PRIMARY OUTCOME MEASURES: The primary outcome was the evaluation of QoL using the Women's Health Questionnaire (WHQ) in all subjects at baseline and after 4, 8 and 12 weeks of treatment. RESULTS: A total of 130 women in the following groups completed the study: tibolone (n=42), Ca/Vit D3 (n=44) and E2/NETA (n=44). An improved QoL based on the WHQ was observed at T0 (80.12±14.04, 77.73±15.3, 77.45±15.4) and T12 (57.0±15.5, 55.7±16.7, 58.4±12.6) for the tibolone, E2+NETA and Ca/Vit D3 groups, respectively (p values <0.05). The three groups exhibited significantly different scores at T12 for sexual behaviour and vasomotor symptoms. The tibolone group exhibited better sexual function compared with the E2/NETA and Ca/Vit D3 groups (4.2±26, 5.6±2.8, 5.4±2.8, respectively, p values <0.05). LD-HT was superior to tibolone and Ca/Vit D3 treatment for improvements in vasomotor symptoms (3.2±1.5, 4.0±1.8, 4.3±2.0, respectively, p values <0.05). Adverse effects were few and mild. CONCLUSIONS: An improved QoL was observed in the three study groups. Tibolone primarily improved sexual function, and E2/NETA exhibited a superior response for vasomotor symptoms.

Effect of abrupt discontinuation versus gradual dose reduction of postmenopausal hormone therapy on hot flushes.

OBJECTIVE: To compare the effects of the abrupt discontinuation of postmenopausal hormone therapy (HT) and reduction of the daily dosage of the hormone on climacteric symptoms. METHODS: The study included Brazilian postmenopausal women who were using estrogen-progestogen hormone therapy in full doses previously prescribed for vasomotor symptoms. The patients were randomized to receive one of three treatments: placebo for 6 months; estradiol (E2) 1 mg/day + norethisterone acetate (NETA) 0.5 mg/day for 2 months, followed by placebo for 4 months; or E2 1 mg/day + NETA 0.5 mg/day for 4 months, followed by placebo for 2 months. The climacteric symptoms were assessed by the Blatt-Kupperman Menopausal Index at baseline and at 2, 4 and 6 months. Statistical evaluation was performed using the chi(2) or Fisher's test for categorical data, the Kruskal-Wallis test for numerical data, and ANOVA for time and group relationship with the Blatt-Kupperman Menopausal Index. RESULTS: We randomized 60 women (20 in each group), and 54 completed the study. It was observed that both the full Blatt-Kupperman Menopausal Index and the hot flush score did not change significantly in the HT group during low-dose therapy compared with baseline; however, the evaluation performed at 2 months after low-dose-HT cessation showed that the full Blatt-Kupperman Menopausal Index and the hot flush score were similar to those of the group who stopped HT abruptly and significantly higher than at baseline (hot flush scores: p < 0.001 for all three groups at months 2, 4 and 6, respectively, vs. baseline). CONCLUSION: Discontinuation of HT by reducing the daily dose of estrogen for a period of 2 or 4 months did not differ in its effect from that of abrupt cessation with regard to vasomotor symptoms.

Effects of estrogen and estrogen-progestogen therapy on homocysteine levels and their correlation with carotid vascular resistance.

OBJECTIVE: To evaluate the correlation between homocysteine levels and carotid vascular resistance in menopausal women submitted to estrogen and estrogen-progestogen therapy. METHODS: Eighty-six women with a mean age of 52 years were enrolled in a prospective, randomized, double-blind, 6-month study. Patients were allocated to use one of three oral therapies: placebo (n = 26), micronized estradiol 2 mg/day (n = 30) or micronized estradiol 2 mg/day plus norethisterone acetate 1 mg/day (n = 30). Evaluation of homocysteine levels and Doppler sonography of the common carotid artery, used to calculate pulsatility index (PI), were carried out prior to initiating therapy and at the end of the study. The correlation between these two parameters was evaluated using Pearson's coefficient of correlation. RESULTS: There was a significant reduction in homocysteine levels in the groups treated with estrogen alone or estrogen combined with norethisterone. PI was significantly lower only in users of estrogen alone; however, no significant correlation was found between homocysteine measurements and PI. CONCLUSION: No significant correlation was found between homocysteine levels and carotid vascular resistance following hormone therapy.

Monophasic estrogen-progestogen therapy and sexuality in postmenopausal women.

OBJECTIVE: This study aimed to evaluate the effects of monophasic estrogen-progestogen therapy on the sexuality and climacteric symptoms of postmenopausal women. PATIENTS AND METHODS: A prospective, randomised, double-blind, crossover, placebo-controlled, single-centre study was carried out over a total of 12 consecutive months in 40 postmenopausal women with an intact uterus who had no contraindications to hormone therapy. Patients received 17beta-estradiol 2mg in combination with norethisterone acetate 1mg (Cliane) daily for 6 months or one placebo tablet daily for 6 months. The tablets were identical in appearance. After 6 months, the groups were crossed over and the patients were followed up for another 6 months. The groups were homogenous with respect to age, height, bodyweight, body mass index and race. For the statistical analysis, the group receiving hormone therapy was referred to as group A and the placebo group was designated group B, irrespective of the placebo/hormone therapy sequence. RESULTS: In group A there were fewer hot flashes (F=22.85, p<0.01) and an improvement in sexual interest (F=5.55, p<0.05). The sequence in which the medication was received resulted in a statistically significant difference with respect to dyspareunia (F=9.65, p<0.01) and satisfaction with the duration of penetration (F=6.58, p<0.05). In the intrapatient analysis of variation with respect to orgasmic capability and the presence of dialogue with partner regarding the couple's sexual life, whether the placebo was taken prior to or following hormone therapy was significant (F=17.12, p<0.001 and F=7.10, p<0.05, respectively). CONCLUSIONS: Monophasic estrogen-progestogen therapy has a beneficial effect on sexuality and on hot flashes in postmenopausal women.

Effects of estradiol alone and combined with norethisterone acetate on pulse-wave velocity in hypertensive postmenopausal women.

BACKGROUND: Arterial hypertension and postmenopausal reduction of estrogen levels may be involved in modifications of the stiffness of large arteries. OBJECTIVES: To evaluate the pulse-wave velocity (PWV) and indirectly the arterial stiffness in hypertensive postmenopausal women submitted to hormone therapy with estradiol alone or combined with norethisterone acetate. SUBJECTS: Forty-five hypertensive postmenopausal women were double-blindly, randomly assigned to three arms of treatment: placebo (group I); estradiol 2 mg/day (group II); or estradiol 2 mg/day and norethisterone acetate 1 mg/day (group III). METHODS: Arterial stiffness was assessed from PWV measurements of the common carotid and femoral arteries (CF-PWV) and the common carotid and radial arteries (CR-PWV) obtained using the automatic Complior(R) device, taken at baseline and after 12 weeks of treatment. RESULTS: After the 12-week treatment, values of CF-PWV and CR-PWV were not significantly different (p = 0.910 and p = 0.736, respectively) among the groups. Systolic blood pressure showed a positive correlation with CF-PWV in groups II and III (p = 0.02 and p < 0.001, respectively). CONCLUSIONS: PWV and arterial stiffness in postmenopausal hypertensive women did not reduce over a 12-week treatment with estradiol alone compared with the same period of treatment with estradiol combined with norethisterone acetate.

Evaluation of mammographic density and (99m)Tc-sestamibi scintimammographic uptake in postmenopausal women on hormone replacement therapy.

OBJECTIVE: To evaluate changes in mammographic density and (99m)Tc-sestamibi scintimammographic uptake in postmenopausal women on hormone replacement therapy (HRT). METHODS: Seventy-five postmenopausal women were prospectively studied and allocated into three groups: 50 women were randomized to either Group 1 (G1, n=25), which received 2mg of 17beta-oestradiol continuously combined with 1mg of norethisterone acetate (E2/NETA, Kliogest, Medley) or Group 2 (G2), which received 2.5mg/day of tibolone (Livial, Organon). The remaining 25 women, who were asymptomatic and had no desire to undergo HRT, constituted the control group (G3). Each patient was submitted to both mammography and scintimammography at baseline and after six months. Mammographic density was evaluated by using the BI-RADS classification system. The classification system of Barros et al. was used in the interpretation of scintimammography. For statistical analysis, the Chi-square test, ANOVA and Pearson's correlation were used. RESULTS: At six months, increased mammographic density was observed in 48% of G1, 12% of G2 and 16% of G3 patients (p<0.001). The increase in sestamibi uptake was 56% in G1, 28% in G2 and 24% in G3 (p<0.001). Increases in both density and uptake were significantly higher in the group on E2/NETA than among tibolone users and the controls. CONCLUSION: In postmenopausal women, HRT with E2/NETA was associated with increased mammographic density and increased (99m)Tc-sestamibi scintimammographic uptakes, suggesting greater mithochondrial activity in the cells of the mammary duct. This was not observed in users of 2.5 mg of tibolone, demonstrating that the effects on the breast were reduced. The same was observed in the control group.

The impact of a monophasic continuous estro-progestogenic treatment on Latin American menopausal women.

OBJECTIVE: The present study was undertaken to assess the impact, effectiveness and safety of a monophasic hormone replacement treatment (HRT) for continuous use with regards to the clinical effects, bleeding patterns and lipid profile of menopausal women in four Latin American countries. DESIGN: Three hundred and six postmenopausal women with natural menopause and uterus present were recruited. This was a multicentre prospective, clinical trial; the participating countries were Brazil (BR), Colombia (CO), Mexico (MX) and Argentina (AR). The study period was 12 months. The HRT regime was formulated in tablets containing 2 mg estradiol E2 and 1mg norethisterone acetate (NETA); one visit every 3 months was solicited. METHODS: HRT was given as one tablet every day without interruption for 1 year. Climacteric complaints, side-effects, reason for discontinuation, bleeding patterns, lipid profile at baseline and 12 months of treatment were documented. RESULTS: There were no significant differences between the four populations on clinical measurements. Thirty-four women discontinued, 13 for bleeding problems. The five most common side-effects were mastalgia, bleeding problems, headache, pelvic pain and nausea. 44.8% of women experienced scanty vaginal bleeding during the first 3 months of therapy. Ninety seven percent of women had amenorrhea at the end of the study in MX, BR and AR, and 100% in CO. Body weight was constant during the study, and no correlation was found between body weight and total days with bleeding. The Kupperman index score was used to evaluate the climacteric complaints, and the score decreased from a mean of 25.4 to 5.1 at 12-months visit. Total cholesterol levels were significantly reduced in BR and CO (P < 0.05) between baseline and the final sample; serum triglycerides remained unchanged, HDL-cholesterol was significantly increased in MX (P < 0.05), and LDL-cholesterol was significantly reduced in CO (P < 0.05). The results of this 1-year study emphasize that a continuous combined HRT regimen with 2 mg E2/1 mg NETA is an attractive alternative for postmenopausal women who are at least 1 year after their menopause and optimally 2 years after their menopause. Although the combination of 2 mg E2 with 1 mg NETA in a continuous combined therapy scheme has been in use in the Nordic countries for over a decade and in Latin America for the last 6 years, there have been no previous published reports on its effectivity in Latin American women. This publication reports the experience in a group of 306 Latin American women, and it is the first Latin American publication with this formulation.

Effect of previous hormone replacement therapy on endometrial polyps during menopause.

The aim of this study was to evaluate the effect of hormone replacement therapy (HRT) on the expression of Ki-67, bcl-2 and c-erb.B2 in endometrial polyps during menopause. Sixteen patients using HRT and 24 untreated controls with endometrial polyps were enrolled in this study. Polypectomy was carried out by hysteroscopy. The presence of c-erb.B2, bcl-2 and Ki-67 expression was determined by immunohistochemistry. HRT was found to decrease Ki-67 and bcl-2 expression in endometrial polyps without affecting the c-erb.B2 staining reaction. HRT may cause endometrial polyp involution by decreasing proliferation and stimulating apoptosis.

Carotid and uterine vascular resistance in short-term hormone replacement therapy postmenopausal users.

OBJECTIVE: To compare the short-term effects of oral hormone replacement therapy (HRT) and placebo on carotid and uterine vascular impedance. METHODS: 80 postmenopausal women selected from the outpatient clinic of the Hospital Leonor Mendes de Barros in São Paulo, Brazil, were randomized to oral HRT (estradiol 2 mg/norethisterone acetate 1 mg-Kliogest(r)) or placebo. Carotid and uterine arteries pulsatility indices (PIs) were assessed by color Doppler at baseline, after 4 and 12 weeks of treatment. Seventy-six women completed the trial, 38 in each group. RESULTS: The carotid PI did not decrease significantly in either group. In the uterine arteries, the drop in PI was steeper and greater for HRT women. Drops occurred despite the supposed counteracting effect of norethisterone acetate. In placebo group, there was no significant difference between 4 and 12 weeks of treatment compared with the baseline. The results did not change when analyzed in a real treatment approach. CONCLUSION: Oral continuous HRT are effective at 12 weeks in reducing impedance to flow in uterine, but not in carotid circulation. These results suggest that the effects of HRT vary by vascular site, and do not have a detectable short-term vascular effect in the carotid area.

Acceptability and patterns of endometrial bleeding in estradiol-based HRT regimens: a comparative study of cyclical sequential combinations of trimegestone or norethisterone acetate.

OBJECTIVE: This randomized, double-blind, multicenter study was planned to compare the efficacy and tolerance of a novel oral regimen containing estradiol (2.0 mg) sequentially combined with trimegestone, at a daily dose of either 0.25 mg or 0.5 mg, with a standard hormone replacement therapy containing estradiol and norethisterone acetate (E2 + NETA) in the treatment of climacteric symptoms. METHODS: The study was conducted over 13 cycles, each of 28 days, and involved 487 subjects, of whom 349 completed the study. RESULTS: All three treatments were equally effective in alleviating hot flushes and showed a progressive and significant reduction in the value of the Kupperman index. The treatments diminished equally effectively urogenital signs and symptoms. All treatments were well tolerated and the incidences of adverse events associated with each treatment were similar across the treatment groups. The duration of expected withdrawal bleeding was shorter in the estradiol + trimegestone 0.5 mg group than in the estradiol + trimegestone 0.25 mg or E2 + NETA group. CONCLUSION: All treatments were effective and well tolerated, providing significant relief from climacteric symptoms. Treatment with estradiol + trimegestone 0.5 mg provided the most favorable bleeding pattern.

Effects of norethisterone acetate and tamoxifen on serum prolactin levels, uterine growth and on the presence of uterine immunoreactive prolactin in estradiol-treated ovariectomized rats.

The aim of the present work was to study the effects of the antiestrogen tamoxifen (TAM), of progestin norethisterone acetate (NA) and of their combination on serum prolactin levels, uterine growth and the presence of uterine immunoreactive prolactin in estradiol-treated rats. Ovariectomized female Wistar rats were injected sc with estradiol valerate (VE, 50 micrograms/rat per week) or oil vehicle. During the second week, estradiol-treated rats also received NA (0.12 or 1.0 mg/rat, sc, daily) or TAM (0.06 mg/rat) alone or in combination with NA (0.12 mg). Serum prolactin levels were suppressed to the same extent in the TAM- and 1.0 mg NA-treated groups compared with rats given estrogen alone (2.3 +/- 0.3 and 5.6 +/- 1.5 ng/ml for TAM and NA groups vs 39.7 +/- 3.6 ng/ml for VE groups, P < 0.05). Except for the lowest dose of NA, uterine wet weight and DNA content were significantly reduced in all groups compared to estradiol alone (236.8 +/- 18.0 and 295.6 +/- 27.8 mg vs 309.4 +/- 32.2 mg for uterine weight in TAM and NA groups vs VE, respectively, P < 0.05; and 1.14 +/- 0.05 and 0.93 +/- 0.04 mg/uterus vs 1.33 +/- 0.06 mg/uterus for uterine DNA in TAM and NA groups vs VE groups). The combination of NA and TAM resulted in a higher degree of suppression of uterine growth than when each drug was used alone, indicating an additive antiproliferative effect of NA and TAM. Although no prolactin immunostaining was detected in the uterus of rats treated with estradiol, uterine immunoreactive prolactin was identified in those treated with NA, TAM or both.(ABSTRACT TRUNCATED AT 250 WORDS)

A multicentre study of coagulation and haemostatic variables during oral contraception: variations with geographical location and ethnicity. Task Force on Oral Contraceptives--WHO Special Programme of Research, Development and Research Training in Human Reproduction.

A comparative study of the effects of combined oral contraceptives (OC) on coagulation and fibrinolytic variables using standardized laboratory technique and methodology has been performed in Dublin (Ireland), Salvador (Brazil), Santiago (Chile) and Singapore. Of 777 entrants to the study, 622 were randomly allocated to receive one of four different OC formulations. The remainder did not opt for OC. The progestogenic component was levonorgestrel (LNG) in three of the OC formulations and norethisterone acetate (NEA) in the fourth. Results for the three LNG user groups were pooled. The changes in haematological variables observed over 12 months in the LNG and NEA users were examined in relation to the changes seen in the women not on OC. Women in Salvador differed markedly from those in the other three centres, in showing no acceleration of the prothrombin time and no increase in either fibrin plate lysis or plasminogen following the use of OC. After adjusting the findings in OC users for those in non-users, significant differences in response between centres were also detected for activated partial thromboplastin time (accelerated only in Dublin and Santiago), factor VII activity (increased mainly in Salvador and Santiago) and fibrinogen (for which the most marked changes were an increase in Dublin and a decrease in Salvador). This variability between centres in the effects of OC on coagulation and fibrinolysis suggests that OC administration in different populations may not carry equal thrombotic risks.

Long-acting hormonal contraceptives for women.

Following the development and widespread use of oral hormonal contraceptives, it became evident that alternative long-acting delivery systems would be required to improve contraceptive practice in some cultural settings where injectable or subdermal routes of administration are preferred. Nowadays, long-acting contraceptives constitute an important option in family planning services in many parts of the world. Indeed, two long-acting injectable contraceptives containing just a synthetic progestogen (depot-medroxyprogesterone acetate (DMPA) and norethisterone enantate (NET-EN)) have been in clinical practice for more than 20 years. The World Health Organization's (WHO) Special Programme of Research in Human Reproduction, in collaboration with the U.S. National Institute of Child Health and Human Development (NICHD) and universities primarily in developing countries undertook a synthesis programme aimed at producing an improved injectable preparation by developing new derivatives of known steroids. One such compound (levonorgestrel 17-butanoate) is now at the stage of Phase II clinical testing. In addition, the Special Programme has developed and improved once-a-month injectable formulations and assessed their safety and efficacy in different countries worldwide. After large scale clinical testing, at least two progestogen-estrogen combinations have reached the point of introductory trials.

PIP: A survey of recent trials of new injectable hormonal contraceptives, progestogen-only, levonorgestrel esters, and once monthly injectables, follows a brief review of all the experimental long-acting contraceptive modalities, injectables, implants, vaginal rings, and hormone-releasing IUDs. Currently medroxyprogesterone acetate (DMPA) and norethisterone enanthate (NET-EN) are being used by 7 million women. WHO is conducting dose reduction trials and studies of bioavailability in various national populations. Even though a dose of 100 mg DMPA every 3 months has been satisfactory for contraception, 150 mg is still recommended until further pharmacodynamic data are available. Some populations, notably Thais and Mexican women, have higher peaks and more rapid elimination rates of DMPA, while Chinese women show slower elimination and higher blood levels of NET-EN. Extensive studies of new synthetic esters of levonorgestrel have proceeded to Phase II clinical trials with levonorgestrel butanoate. This ester is an effective contraceptive for 3 months at 12.5 mg, or 5-6 months at a dose of 25 or 50 mg. Trials of combined estrogen and progestogen injectables once-monthly have been ongoing for 10 years. The ratio of the 2 components is as important as the amounts. 2328 women from 12 countries participated in trials of DMPA 25 mg-estradiol cypionate 5 mg, and NET-EN 50 mg-estradiol valerate 5 mg. The continuation rate was better than that for 3-monthly progestogen-only injectables, because of less irregular bleeding. A combined injectable called Cyclofem, DMPA 25 mg-estradiol cypionate is being introduced in several countries. The steadily increasing demand for long-acting injectables prompts development of better formulations.