A multicenter comparative study on the efficacy, safety, and acceptability of the contraceptive subdermal implants Norplant and Norplant-II

Design of a Drug-Eluting Subcutaneous Implant of the Antiretroviral Tenofovir Alafenamide Fumarate

PURPOSE

Sexual transmission of HIV has been clinically proven to be preventable with a once-daily oral tablet; however, missed doses dramatically increase the risk of HIV infection. Long-acting subcutaneous implants do not allow the user to miss a dose. A desirable long-acting drug-eluting implant can deliver a constant amount of drug, adjust the delivered dose, and be readily manufactured. We present a long-acting, subcutaneous implant design composed of tenofovir alafenamide hemifumarate (TAF) pellets loaded in a sealed polyether urethane tube for the prevention of HIV transmission.

METHODS

Implants were prepared with pressed drug pellets and extruded polyurethane tubing. In vitro release rate of implants using different pellet formulations, rate-controlling membranes, and geometries were measured.

RESULTS

Tenofovir alafenamide release appeared to be governed by a pseudo-steady state and followed a mass transport model of release from a cylindrical drug reservoir. Implant seal integrity was tested and confirmed using mechanical testing. The inclusion of sodium chloride in the pellet increased the release rate and reduced initial lag. The release was sustained for 100 days.

CONCLUSIONS

The release rate of tenofovir alafenamide mechanistically varied with geometry and rate controlling membrane composition. The polyether urethane implant presented herein is modular and tunable to adjust the release rate and duration of the TAF release.

Preventing unintended pregnancy among young women in Kenya: prospective cohort study to offer contraceptive implants

BACKGROUND

Subdermal contraceptive implants have low discontinuation rates but are underused among young women in Africa. This study aimed to isolate the role initial contraceptive method has on preventing unintended pregnancy.

STUDY DESIGN

We recruited 399 Kenyan women aged 18-24 years into a prospective cohort study if they wanted short-acting hormonal methods (injectable or oral contraceptives). We offered an implant and formed two study groups: implant and short-acting. For contraceptive discontinuation/pregnancy, we used log-rank tests and proportional hazards models. We applied intent-to-treat principles to evaluate the role of initial method choice on future pregnancy.

RESULTS

Twenty-four percent opted for an implant (n=97), and the remainder opted for a short-acting method (n=299). The 18-month discontinuation probability was 21 per 100 for implant users and 43 per 100 for the short-acting method group (p=.001). Twenty-two unintended pregnancies occurred; all were among the short-acting group. The adjusted relative risk of pregnancy among the short-acting group vs. implant group was 7.4 (95% confidence interval: 1.6-34.5).

CONCLUSIONS

Many young Kenyan women found implants to be a reasonable alternative to short-acting methods. Having choice is essential, and starting on implants provides substantial and clear protection from unintended pregnancy relative to short-acting methods.

Menstrual pattern changes from levonorgestrel subdermal implants and DMPA: systematic review and evidence-based comparisons

BACKGROUND

Many women want a lengthy duration of contraception but are wary of the menstrual changes from depot medroxyprogesterone acetate (DMPA). A subdermal levonorgestrel (LNG) implant may be a reasonable alternative. However, information on menstrual changes from these methods has not been summarized and compared in an easy-to-understand form.

STUDY DESIGN

We systematically reviewed the published literature on these contraceptives to find research that used menstrual diaries and standard World Health Organization definitions. We attempted to find information on amenorrhea, number of bleeding or spotting episodes, number of bleeding or spotting days and normal patterns, as reported in four consecutive 90-day reference periods.

RESULTS

We found 16 published articles meeting our criteria and involving diaries of up to 1600 DMPA users and 2300 LNG implant users. We were able to compare the two methods on only three outcomes. For DMPA use, the weighted prevalence of amenorrhea at successive 90-day periods was 12%, 25%, 37% and 46%. The comparable estimates for the LNG implant were 11%, 13%, 9% and 13%. Levonorgestrel implant users experienced a higher average number of bleeding or spotting days compared to DMPA users, but this average was similar to what is expected naturally. At 12 months, normal menstrual patterns were experienced by 23% of LNG implant users compared to 11% of DMPA users.

CONCLUSIONS

Like most hormonal contraception, LNG implants usually produce menstrual changes; however, the changes do not appear to deviate from normal patterns as much as the changes from DMPA. Understanding these differences and other method attributes might help women make an informed choice about which contraceptive to use.

Effects of doxycycline on serum and endometrial levels of MMP-2, MMP-9 and TIMP-1 in women using a levonorgestrel-releasing subcutaneous implant

BACKGROUND

Endometrial spotting and/or bleeding (ESB) occurs in levonorgestrel subcutaneous implant (LNG SI) users. Matrix metalloproteinases (MMPs) may play a role in ESB.

STUDY DESIGN

Women between 18 and 40 years with regular menstrual cycles had a baseline evaluation followed by LNG SI insertion and randomization to doxycycline (DOX; 20 mg) or placebo (PL) twice a day. MMP-2, MMP-9 and tissue inhibitor of MMP-1 (TIMP-1) in serum and the endometrium were estimated at baseline and at 1, 3 and 6 months after insertion.

RESULTS

LNG increased serum MMP-9, while DOX decreased MMP-9 levels compared to PL after 1 month (p<.05). DOX decreased endometrial MMP-9 at 1 and 6 months compared to baseline and PL (p<.05). DOX increased endometrial TIMP-1 at 6 months compared with baseline and PL (p<.05). MMP-2 levels were unchanged.

CONCLUSION

LNG SI increased serum MMP-9 and TIMP-1 levels, while DOX decreased both serum and endometrial MMP-9 levels.

Removal of etonogestrel contraceptive implants in the operating theater: report on 28 cases

OBJECTIVES

We describe removal procedures for etonogestrel contraceptive implants in the operating theater. In addition, we discuss the management of removal of contraceptive implants that are difficult to palpate or are impalpable.

DESIGN

We conducted a retrospective single-center case series analysis of Implanon removals conducted at a university hospital between January 2002 and April 2005.

MATERIALS AND METHODS

We analyzed case notes for 28 patients who had their contraceptive implant removed in the operating theater.

RESULTS

Intermenstrual bleeding was the principal reason for removal (52.4%). Ten patients already had one attempted removal of their implant. Preoperative ultrasound localized the implant in all cases. Half of the removals were done under local anesthetic, with three cases progressing to general anesthesia (11%). Thirty percent of the implants had migrated from their initial implantation, 37% were in intramuscular tissue and 11% were in the humeral neurovascular sheath. The only postoperative complications were one small seroma and transient paresthesia in the territory of the ulnar nerve. The implant was not found in one case.

CONCLUSIONS

The removal of an implant that is not palpable or difficult to palpate should take place in the operating theater following localization by ultrasound. Patients must be fully informed about the procedure, including its complications and the risk for failure.

Evaluation of haemostatic function in Nigerian Norplant acceptors after 12 months of use

A total of 55 non-breastfeeding informed volunteers were recruited into a prospective longitudinal study from a family planning clinic between September and December 2002. Blood samples were collected at pre-treatment and at 3, 6 and 12 months follow-up, for packed cell volume, platelet count, prothrombin and activated partial thromboplastin time. Statistical analysis was with paired t-tests. The level of significance was set at 5%. Each subject received a menstrual calendar to chart all bleeding and spotting events. The mean age and weight of acceptors were 32.5 +/- 6.1 years and 63.6 +/- 9.6 kg, respectively. Mean packed cell volume (PCV) was 35.2 +/- 2.9% at pre-insertion. This rose to significant mean +/- SD values of 36.5 +/- 3.1%; p<0.05, 38.5 +/- 2.8%; p<0.0001 and 38.4 +/- 3.6%; p<0.0001 at 3, 6 and 12 months, respectively when compared with the pre-insertion mean value. The mean values of the platelet count showed no significant change at 3 months (238,448 +/- 68,618 mm(3); p>0.9), compared with pre-treatment value (240,545 +/- 96,769 mm(3)). There was a significant reduction in mean concentration at 6 months (p<0.009; 191,364 +/- 55,531 mm(3)) and at 12 months (p<0.003; 202,773 +/- 81,544 mm(3)) follow-up. The prothrombin and the partial thromboplastin time did not show significant change over their pre-insertion mean values of 12.0 +/- 1.1 s and 36.9 +/- 2.9 s, respectively. At 12 months, 79.5% (35) of the users reported an abnormal menstrual pattern, which included 54.5% (24) reduced bleeding pattern, 20.5% (9) increased bleeding and 4.5% (2) of combination of patterns. Only 20.5% (9) had a normal menstrual pattern. The continuation rate was 98%, as one user discontinued because of headaches. Norplant (the registered trademark of the Population Council for levonorgestrel subdermal implants) had an effect on the bleeding pattern - mainly reduced bleeding. The increase packed cell volume is beneficial in preventing anaemia. There was no detrimental effect as a result of the reduced but normal platelet count and users were not predisposed to clotting abnormalities.

Acceptability of levonorgestrel subdermal implants versus tubal ligation for long-term contraception in a rural population of Zimbabwe

This prospective cohort study of 257 rural Zimbabwean women was designed to compare patient satisfaction with levonorgestrel subdermal implants (Norplant and reg;) versus tubal ligation (TL) as a method of long-term contraception. Women were equally satisfied with both methods. At 1 year, 96% of Norplant users and 97% of the TL group reported being "satisfied" or "very satisfied," and 98% of Norplant users, and 99% of the TL cohort would recommend their chosen method to a friend or relative. Rating scores at both 6 months and 1 year were high and equal, with women in each cohort rating their method, on average, as 9 out of 10. Norplant users were significantly more likely to rate birth spacing as a reason for satisfaction with their method, whereas women in the TL cohort were more likely to select multiparity. The 1-year continuation rate with Norplant was 90%, with 4% discontinuing in order to have more children. Selecting the most appropriate method depends primarily on the potential desire of the woman to have more children.

Development and validation of an acceptability and satisfaction questionnaire for a contraceptive vaginal ring, NuvaRing

OBJECTIVE

To validate an acceptability questionnaire for NuvaRing, a new combined contraceptive vaginal ring.

METHODS

A 21-item questionnaire was developed covering: ease of ring use, ease of package use, clarity of instructions, sexual comfort, cycle-related characteristics, compliance and satisfaction. A total of 2145 women completed the questionnaire after 3, 6 or 13 cycles of NuvaRing use. The psychometric properties and predictive value of the questionnaire were assessed using cycle 3 data (n = 1950). The quality of completed questionnaires, item content analysis, construct validity, internal consistency reliability, known groups validity and predictive validity were evaluated.

RESULTS

Excluding non-ordinal items, 0.6% of the data were missing. Principal component analysis of 15 ordinal items indicated that two hypothesised dimensions ('ease of package use' and 'clarity of instructions') were consistently linked and so were combined into a single 'ease of comprehension' scale. Item convergent validity (the degree of correlation between an item and its own scale) was 100% for 'ease of ring use' (r = 0.44) and 'satisfaction' (r = 0.58), 83% for 'ease of comprehension' (r = 0.25-0.62) and 67% (r = 0.38-0.54) for 'sexual comfort', but 0% for 'cycle-related characteristics' (r = 0.31). Item discriminant validity (the degree to which an item correlates with its own scale compared with other scales) was >/=96% for all dimensions. Internal consistency reliability was acceptable for all dimensions (adjusted Cronbach's alpha coefficient >0.70). Satisfaction was higher than in the complementary groups for respondents who had no adverse events, chose NuvaRing as the best method of contraception or completed the study; this indicated good known groups validity. Low satisfaction with the method was a good predictor of early discontinuation after cycle 3, indicating that the questionnaire had good predictive validity.

CONCLUSIONS

The acceptability questionnaire has good psychometric properties and can predict early discontinuation of the NuvaRing vaginal ring method of contraception.

Local side effects observed among long-term users of norplant contraceptive implants

The prevalence of local signs and symptoms related to the site of insertion of implants, and the association of these signs and symptoms with time of use, skin color and body mass index (BMI) was evaluated among users of the Norplant implant system. Three hundred and three Norplant users attending at the reproductive health clinic of PROFAMILIA in Santo Domingo, Dominican Republic, were asked if they had ever had any discomfort at the site/arm of implant insertion and the implant insertion area was examined and hyperpigmentation and hollowing of the surface was recorded. Half of the subjects reported either pain or paresthesia or both, in almost equal numbers, some time since insertion. Hyperpigmentation was observed in 35.6% and hollowing in 22.4% of the subjects. Report of pain and paresthesia was inversely associated to time of use and to BMI. Hyperpigmentation was directly associated to time of use and darker skin, and hollowing of the arm surface in the implants area with time of use and BMI. Local signs and symptoms were more frequent than previously reported, although they were of mild nature and appeared not to worry most of the users.

Risk-benefit effects of implantable contraceptives in women

Contraceptive implant technology has been used by millions of women throughout the world. The three marketed implant systems today are levonorgestrel-releasing implants: Norplant and Jadelle, and a single etonogestrel-releasing implant, Implanon. The main benefits common to these delivery systems are their safety, high effectiveness, ease of use, long duration of action (3 - 5 years) and reversibility. Bleeding disturbances are the main adverse events associated with implantable contraceptives. Other minor risks relate to the insertion and removal procedures, which require adequately trained providers as well as aseptic techniques. Furthermore, since initiation and discontinuation of use is provider-dependent and not controlled by the user, there may be a risk of coercion of use on the one hand or, on the other hand, difficulty in access to initiating use, if trained providers are not readily available. Although no single contraceptive method is perfect or appealing to all, contraceptive implants are safe and fulfil a very important need among fertility regulation methods.

Hormone-like behavioral effects of levonorgestrel and its metabolites in the male rat

Levonorgestrel (LNG), a contraceptive progestin, exhibits, besides its progestational activity, other hormone-like effects at the peripheral level. To assess whether LNG and its metabolites exert androgenic and/or estrogenic actions at the central nervous system (CNS), their effects on male sexual behavior in castrated rats were examined. LNG, 5alpha-dihydro LNG (5alphaLNG), and the 3alpha,5alpha- and 3beta,5alpha-tetrahydro derivatives of LNG (3alphaLNG and 3betaLNG, respectively) were administered for 3 weeks either alone (1000 microg/day) or in combination (300 microg/day) with 5alpha-dihydrotestosterone (DHT, 300 microg/day) or with estradiol-17beta (E(2), 5 microg/day). Copulatory behavior was assessed twice per week and sex accessory organs weights recorded at the end of treatments. LNG restored full copulatory behavior comparable to that of testosterone treated animals, although with a slight delay, whereas 5alphaLNG induced male sexual behavior in a significantly lower number of subjects. 3betaLNG and 3alphaLNG induced mounting but failed to restore intromission and ejaculation. Combined LNG+E(2) treatment fully activated mounting and intromission, but ejaculation was only partially restored. Combined 5alphaLNG+E(2) treatment and the combinations of 3alphaLNG or 3betaLNG with E(2) were significantly less effective, activating fewer intromissions and ejaculations. 3alphaLNG and 5alphaLNG, in combination with DHT, restored male sexual behavior. LNG, but not its metabolites, induced a significant increase on the weight of sex accessory organs. The overall results demonstrated that high doses of LNG induce a potent androgen agonistic behavioral effect and that its A-ring reduction diminishes this potency and enables a shift towards a weak estrogen-like effect.

Nonmenstrual adverse events during use of implantable contraceptives for women: data from clinical trials

Contraceptive methods, including implants, do not prevent common symptoms and adverse health events that most people experience. It is difficult, therefore, to decide whether or not the occurrence of symptoms or adverse events that are common can be attributed to use of a contraceptive method or to determine if a given method changes the likelihood of their occurrence. Based on the review of the literature, no apparent differences in the frequency of adverse events are evident between the six-implant or two-rod levonorgestrel systems and the single implant etonogestrel and nomegestrol acetate systems. The most frequent adverse events reported in clinical trials that are probably related to implant use are headaches and acne. Weight gain, dizziness, and mood changes are also frequently mentioned adverse events and are possibly steroid-related. Other possibly related adverse events, although much less frequently reported, are loss of libido, fatigue, hair loss, and other skin conditions. Persistent ovarian follicles that spontaneously disappear are a common event during use of progestin-only contraceptives, and providers should be aware of this condition to avoid unnecessary interventions. Overall, the vast experience reported in the clinical studies reviewed here show that all existing implantable contraceptives are equally safe. This can probably be attributed to the low-hormonal dose delivered by progestin-implant systems.

A 4-year follow-up study of women with Norplant-2 contraceptive implants

One-hundred-thirty of 178 women who received Norplant-2 implants were followed prospectively for 4 years. Menstrual disorders were the most common reason for discontinuation. Only one patient conceived, for a failure rate of 0.6%.

Assessment of the oestrogenic activity of the contraceptive progestin levonorgestrel and its non-phenolic metabolites

Levonorgestrel (13beta-ethyl-17alpha-ethynyl-17beta-hydroxy-4-gonen-3-one), a potent contraceptive progestin stimulates growth and proliferation of cultured breast cancer cells through a receptor-mediated mechanism, even though levonorgestrel does not bind to the oestrogen receptor (ER). To assess whether the oestrogen-like effects induced by this synthetic progestin are exerted via its metabolic conversion products, we studied the binding affinity of three A-ring levonorgestrel derivatives to the ER and their capability to transactivate an oestrogen-dependent yeast system co-transfected with the human ER gene and oestrogen responsive elements fused to a beta-galactosidase reporter vector. The results demonstrated that the 3beta,5alpha reduced levonorgestrel derivative and to a lesser extent its 3alpha isomer interact with the oestrogen receptor, with a significantly lower relative binding affinity (2.4% and 0.4%, respectively) than that of oestradiol (100%), while levonorgestrel does not. Both levonorgestrel metabolites were able to activate, in a dose-dependent manner, the beta-galactosidase reporter gene in the yeast expression system, an effect that was precluded by a steroidal antioestrogen. The oestrogenic potency of levonorgestrel metabolites was significantly lower (750-fold) than that of oestradiol. Furthermore, high doses of 3beta,5alpha levonorgestrel (2.5 mg/day/6 days) induced an increase of oestrogen-dependent progestin receptor in the anterior pituitary of castrated rats. The overall data offer a plausible explanation for the weak oestrogenic effects induced by high, non-pharmacological doses of levonorgestrel.

Patient-reported experience with the Viadur 12-month leuprolide implant for prostate cancer

OBJECTIVES

To assess patient-reported general satisfaction, effect on daily activities, and effect on health-related quality of life of a 12-month leuprolide implant for prostate cancer.

METHODS

A total of 80 men with prostate cancer participated in an open-label Phase III study of the Viadur leuprolide implant. One implant was inserted in each patient at enrollment and was removed after 52 weeks. At 24 and 52 weeks after implantation, patients were asked to complete a questionnaire about their experience with the implant, and at 0, 12, 24, 36, and 52 weeks after implantation, the patients were asked to complete the Medical Outcome Study Short Form-36 health-related quality-of-life instrument.

RESULTS

The surveys about the patients' experience with the implant were completed by 70 subjects, and two or more SF-36 questionnaires were completed by 72 patients. At weeks 24 and 52 after implantation, greater than 90% of patients were extremely satisfied or satisfied with the overall treatment, found the implant convenient, forgot about the implant most of the time or were occasionally aware of the implant, and found the implant very comfortable or somewhat comfortable. No meaningful change was found in the summary scores of the mental and physical aspects of the SF-36 assessments during treatment. Of 73 men who were eligible for reimplantation after the 12-month study period, 70 (96%) elected to undergo reimplantation.

CONCLUSIONS

In this study, patients found the Viadur 12-month leuprolide implant convenient, and the implant did not affect their health-related quality of life.

Headache and female hormones: what you need to know

The normal female lifecycle is associated with hormonal milestones, including menarche, pregnancy, contraceptive use, menopause, and the use of replacement sex hormones. Attacks of migraine without aura, but not with aura, are more likely to occur 2 days before onset and on the first 2 days of menses, but they are not more severe than those that occur outside the perimenstrual period. Oral sumatriptan and naratriptan are effective as short-term perimenstrual prophylaxis. Postdural headache can occur during the postpartum period. The International Headache Society Task Force assessed the efficacy of treatment of women who had migraine with combined oral contraceptives and hormone replacement therapy, as well as the risk of ischemic stroke associated with their use. There is no contraindication to the use of oral contraceptives in women with migraine in the absence of migraine aura or other risk factors. There is a potentially increased risk of ischemic stroke in women with migraine who are using combined oral contraceptives and have additional risk factors that cannot easily be controlled, including migraine with aura. There is no compelling evidence that postmenopausal hormone replacement therapy either decreases or increases stroke risk.

Norplant: reasons for discontinuation and side-effects

OBJECTIVE

To study the side-effects and reasons for the discontinuation of Norplant.

METHODS

The study was based on the analysis of the medical records of 265 Norplant users, who obtained Norplant from two clinics of the Family Planning Association of Pakistan and who were followed for 5 years.

RESULTS

The most common reason (29.4%) for the discontinuation of Norplant was menstrual disturbances, followed by medical problems (4.1%), desire for more children (3.1%) and family problems (3.1%). The major side-effects were weight gain, breast tenderness, headache and dizziness. Only 7.7% of users mentioned any change in sexual behavior and 69.6% of the complaints leading to Norplant removal developed within 6 months of insertion.

CONCLUSION

The extent and nature of the side-effects experienced by Pakistani women using Norplant are similar and comparable to those reported from other countries.

A 10-year follow-up study of contraceptive Norplant implants

OBJECTIVES

To evaluate the long-term efficacy and health problems associated with Norplant implants and re-implants after 5 full years of first implants.

METHOD

From 1984 to 1988, 1657 women accepted first implants of Type I and Type II of Norplant, and 394 first acceptors had a re-implant, at a clinic for study. The clinical records and annual follow-up data of acceptors were analyzed. The life-table technique was the main method used.

RESULTS

The continuation rates were very high. The cumulative pregnancy rates at 1, 3 and 5 full years of use were 0.0%, 0.1% and 0.7%, respectively. Users with heavier body weight had higher pregnancy rates. The rate of menstrual disturbances peaked at 73% after 3 months and consistently decreased to 20% at 5 years of use. Rates of menstrual disturbances associated with re-implants were much lower.

CONCLUSION

Norplant is extremely effective and safe for long-term use.

A randomized multicenter study comparing the efficacy and bleeding pattern of a single-rod (Implanon) and a six-capsule (Norplant) hormonal contraceptive implant

To compare the contraceptive efficacy, tolerability, and bleeding patterns, 200 healthy female volunteers received, in an open, comparative, randomized, multicenter study in China, either a single-rod (Implanon) or a six-capsule (Norplant) contraceptive implant for 2 years with an optional extension of up to 4 years. Women were exposed to Implanon for 341.6 woman-years and Norplant for 329.1 woman-years. There were no pregnancies during the study. Per 90-day reference period, the median number of bleeding/spotting days with Implanon decreased from 33.5 in the first period to 19.0-21.5 days in the last year. Similarly, with Norplant, the median number of bleeding/spotting days decreased from 34.5 to 18.0-23.0 days, respectively. The number of bleeding/spotting episodes during year 1 was 2.0 per 90-day reference period with Implanon and 3.0 per period with Norplant (p < 0.05 for periods 1-4). For the remaining 90-day periods, there was no statistical difference between the two groups. In general, there was less frequent bleeding with Implanon compared with Norplant, whereas the incidences of amenorrhea and infrequent bleeding were higher with Implanon than with Norplant. The mean overall incidence of prolonged bleeding fell markedly during the study, from 66.0% in reference period 1 to 27.3% in period 16 with Implanon and from 69.0% to 21.7% with Norplant, respectively. The most common adverse events were related to disturbed bleeding patterns, which were also the major reasons for discontinuation (Implanon n = 8; Norplant n = 14). Normal menses returned in almost all subjects within 3 months after removal of the implants. Implanon was inserted in a mean time of 0.61 min and Norplant in 3.90 min (p < 0.001). Similarly, the mean time required to remove the implant was significantly shorter for Implanon than for Norplant (2.18 min vs 11.25 min, p < 0.001). The maximum time required for removal of the implant was 10 min for the Implanon group and 60 min for the Norplant group. In both groups, blood pressure and hemoglobin were not affected, whereas body weight tended to increase. It can be concluded that both contraceptive systems demonstrated excellent contraceptive efficacy and were well tolerated. Compared with Norplant, there was less frequent bleeding with Implanon, whereas the incidence of infrequent bleeding and amenorrhea was higher. Implanon was significantly quicker to insert and to remove than was the multiple capsule system.

A long-term study of the efficacy and acceptability of a single-rod hormonal contraceptive implant (Implanon) in healthy women in China

OBJECTIVE

To investigate the contraceptive efficacy, cycle control and acceptability of Implanon, a new single-rod, progestogen-only contraceptive implant.

METHODS

In a non-comparative, open, multicenter study, a contraceptive implant containing the progestogen etonogestrel was inserted into 200 healthy women. The study duration was 2 years, with an optional extension up to 4 years.

RESULTS

Women were exposed to Implanon for 644.6 woman-years. There were no pregnancies during the study. Per 90-day reference period, the median number of bleeding-spotting days ranged between 18 and 21 and the median number of bleeding-spotting episodes was two. The mean overall incidence of prolonged bleeding fell markedly during the study, from 69% in the first reference period to 26% in the 16th period. The most common adverse events were related to disturbed bleeding pattern and amenorrhea. Heavy or prolonged bleeding caused 18 subjects to withdraw from the study. Only a few subjects discontinued the study early due to irregular bleeding (2%) or amenorrhea (2%). A slight increase in mean body weight was observed. The implant was removed in an average time of 2.9 min.

CONCLUSIONS

Implanon demonstrated excellent contraceptive efficacy for 4 years of use and was well tolerated. The incidences of prolonged bleeding and amenorrhea both fell markedly with continued implant use. Because of its single-rod design, Implanon was quickly removed with few complications and proved to be a highly acceptable method of contraception.

A pilot efficacy study with a single-rod contraceptive implant (Implanon) in 200 Indonesian women treated for < or = 4 years

In this 4-year open-label, noncomparative, single-center pilot efficacy study, the contraceptive efficacy, safety, bleeding pattern and acceptability of Implanon was studied in 200 sexually active women of proven fertility in Indonesia. All subjects received the single-rod subdermal implant Implanon, which contains 68 mg etonogestrel (3-keto-desogestrel), with an initial release rate of 67 micrograms etonogestrel/day. Contraceptive efficacy was analyzed by calculation of the pregnancy rate, bleeding patterns were determined by the 90-day reference period method, and acceptability by the discontinuation rate. No in-treatment pregnancies were reported during 658.4 women-years of exposure, resulting in a Pearl Index of 0.0 (95% CI 0.0-0.6). The overall bleeding pattern was acceptable, with no discontinuations because of irregular bleeding. Incidence of irregular bleeding was highest during the first two reference periods and decreased thereafter. Amenorrhea was experienced by 7%-12% of subjects during years 1 and 2, by 5%-7% during year 3, and by 2%-5% during year 4, with one discontinuation because of amenorrhea. No clinically significant changes were reported for systolic and diastolic blood pressure, body mass index, and hemoglobin level. Three adverse experiences were related to treatment and resulted in discontinuation (two headaches and one dyspnea). One difficult implant removal was reported. In conclusion, this pilot efficacy study indicates that Implanon provides excellent contraceptive reliability and an acceptable bleeding pattern. Overall safety and acceptability are good, as suggested by the low incidence of adverse experiences and the low discontinuation rate.

A 4-year pilot study on the efficacy and safety of Implanon, a single-rod hormonal contraceptive implant, in healthy women in Thailand

OBJECTIVE

To investigate the contraceptive efficacy, safety and acceptability of a new single-rod, progestogen-only contraceptive implant (Implanon).

METHODS

In an open, non-comparative pilot study, 100 healthy women received a contraceptive implant containing the progestogen etonogestrel (3-ketodesogestrel) for 2 years with an optional extension up to 4 years.

RESULTS

Subjects were exposed to Implanon for 296.1 woman-years. There were no pregnancies during the study. Per 90-day reference period, the median number of bleeding-spotting days was 10 and the median number of bleeding-spotting episodes was 2. Amenorrhea occurred in 24-39% of subject during the first 2 years and in about 20% in those who continued in the 3rd and 4th years. The most common drug-related adverse event was headache (7%). A slight increase in body mass index was observed. Only a few subjects discontinued treatment early, due to bleeding irregularities (6%) or amenorrhea (1%). The cumulative discontinuation rates were 13.4% after 2 years, 25.3% after 3 years and 28.0% after 4 years of use. Within 3 months of implant removal, six normal pregnancies occurred, indicating a rapid return of fertility. The average time taken for insertion of the implant was 0.5 min, compared with 2.5 min for removal.

CONCLUSIONS

Implanon demonstrated excellent contraceptive efficacy and was well tolerated during up to 4 years of use. The vaginal bleeding pattern was variable and was characterized by relatively few bleeding events, but proved acceptable to most subjects. Because of its single-rod design, Implanon was quickly inserted and removed without complications.