Safety and efficacy of Implanon, a single-rod implantable contraceptive containing etonogestrel

OBJECTIVES: The safety and efficacy of a single-rod implantable contraceptive containing etonogestrel (Implanontrade mark) were investigated in a multicenter clinical trial. STUDY DESIGN: Sexually active American women (N=330) with apparently normal menstrual cycles used the implant for up to 2 years. All subjects recorded bleeding and/or spotting daily in a diary. Safety was assessed through adverse experiences (AEs), laboratory tests and physical and gynecologic examinations. RESULTS: Total exposure was 474 woman-years (6186 cycles), and 68% of subjects had at least 1 year of exposure. No pregnancies occurred. The most common bleeding pattern observed throughout the study was infrequent bleeding, defined as less than three episodes of bleeding in a reference period (excluding amenorrhea). The least common pattern was frequent bleeding, defined as more than five episodes of bleeding in a reference period. Infrequent, prolonged and frequent bleeding patterns were most common early in the study and declined thereafter. During the 3-month Reference Periods 2-8 (Months 4-24), the incidence of amenorrhea ranged from 14% to 20%. Forty-three subjects (13%) withdrew from the study because of bleeding pattern changes and 76 subjects (23%) discontinued because of other AEs. Other common AEs leading to discontinuation, besides bleeding irregularities, were emotional lability (6.1%), weight increase (3.3%), depression (2.4%) and acne (1.5%). Use of Implanon (etonogestrel subdermal implant, referred to herein as ENG implant) for up to 2 years had no clinically significant effects on laboratory parameters, physical and pelvic examinations, vital signs or body mass index. The average length of time required for ENG implant insertion and that for removal were 0.5 and 3.5 min, respectively, and all the procedures were uncomplicated. The return to normal menstrual cycles and fertility was rapid after removal. CONCLUSIONS: Implanon is a safe, highly effective and rapidly reversible new method of contraception.     

三种皮下埋植避孕剂对农村妇女月经影响的比较性研究

采用随机方法在辽宁省北宁地区选择40岁以下健康经产妇女埋入国产Ⅰ型、Ⅱ型和Norplant皮埋剂各100例,按照统一标准随访,对于皮埋后主要副反应月经问题进行追踪观察和分析。结果:由于人们已经逐渐了解皮下埋植避孕法,尤其农村妇女对其引起不垫月经垫的出血的耐受力较强,主诉月经问题及月经日记分析的流血、滴血天数低于以往文献报道,主要是因平均滴血天数不同的原因。埋植者对月经稀发问题并不反对,对埋后闭经者约半数可接受。通过月经日记分析,在使用第一年约有70％妇女出现月经异常,与文献报道相符。对于典型的异常出血(包括年度内出现≥90天不出血者和出现持续出血≥14天者)对接受者体重并无影响,三组P>0.05。三组埋植者血红蛋白在正常范围内有增无减,至2年均有显著差异,P<0.01。本文提示皮下埋植后妇女可能改变既往传统的月经规律,只要不是长期不规则出血、出血期过长及出血过频较严重或过长的闭经则不必担心,也不需处置,良好的咨询及等待即可,一般可接受的异常出血对妇女健康并无影响,埋植剂一经取出,大部分在60天内恢复月经。     

国产Ⅰ型、Ⅱ型埋植剂与Norplant使用第1年阴道出血模式的观察与比较

为了解两种国产埋植剂对阴道出血模式的影响,并与Norplant进行比较,对自1993年11月1日～1994年5月31日随机接受的857例埋植剂使用者记录的月经卡(其中国产Ⅰ型288份,国产Ⅱ型292份,Norplant277份),采用WHO推荐的参考时段法进行统计分析。结果:各项统计指标三组间差异均无显著意义;总出血天数和滴血天数各参考时段均有减少,自第3参考时段起差异有显著意义;各种出血类型的发生率三组间无差异,有基本正常出血类型的人数自第2参考时段明显增加,为30％～35％;出血不规则的发生率自第2参考时段明显减少,为34％～41％,但仍为各种异常出血的首位;再次使用埋植剂者的总出血天数和出血天数均少于首次使用者,差异有显著意义。初步认为两种国产埋植剂在使用后第1年中对阴道出血模式的影响与Norplant相似,阴道总出血天数随滴血天数的减少而缩短;与使用初期相比,使用三种埋植剂后三个月,有基本正常出血类型的人数明显增加,出血不规则的发生率明显减少,出血不规则是埋植剂使用后月经紊乱的主要表现;再次使用者的出血情况好于初次使用者。     

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.     

Contraceptive implants and lactation

The safety and efficacy of four contraceptive implants, plant, Implanon, Nestorone and Elcometrine, have been evaluated during use in the postpartum period by lactating women. These implants provide highly effective contraceptive protection with no negative effect on breastfeeding or infant growth and development. Breastfeeding women initiating Norplant use in the second postpartum month experience significantly longer periods of amenorrhea than do untreated women or intrauterine device users. After weaning, the bleeding pattern is similar to that observed in non-nursing women. Norplant use does not affect bone turnover and density during lactation. Norplant and Implanon release orally active progestins while Nestorone and Elcometrine implants release an orally inactive progestin, which represents an advantage since the infant should be free of steroidal effects. The infant's daily intake of steroids (estimated from concentrations in maternal milk during the first month of use) range from 90 to 100 ng of levonorgestrel (Norplant), 75-120 ng of etonogestrel (Implanon), and 50 ng and 110 ng of Nestorone (Nestorone and Elcometrine implants, respectively). Nursing women needing contraception may use progestin-only implants when nonhormonal methods are not available or acceptable. Implants that deliver orally active steroids should only be used after 6 weeks postpartum to avoid transferring of steroids to the newborn.     

Vaginal bleeding patterns among women using one natural and eight hormonal methods of contraception

Menstrual diary records were obtained from a total of 5257 women using nine different methods of contraception, one natural and eight hormonal. This paper presents a comparative analysis of their vaginal bleeding patterns. The analytic procedures follow the recommendations of a recent WHO workshop on bleeding pattern analysis, which involve dividing each subject's diary into successive 90-day reference periods, calculating ten indices for each period, and classifying women according to whether they have "clinically important" bleeding disturbances. In general, the findings of this analysis confirm those of previous studies. Women using the natural method, who were deliberately selected for the regularity of their menstrual cycles, averaged three bleeding/spotting episodes of length 5 days in each 90-day period, with very little variability within or between women. Subjects given a combined oral contraceptive had more regular patterns than any other treated group, with short (4-day) episodes and 23-24 day bleeding-free intervals. Progestogen-only pill users had more frequent, longer episodes and shorter, less predictable intervals than combined pill users. Contrary to widely-held beliefs, the progestogen-only pills produced fewer spotting days than the combined pills, and almost no spotting episodes at all. Nearly half of vaginal ring users experienced some menstrual disturbance in each period; their most common problems were irregular, infrequent or prolonged bleeding. Women using the long-acting injectable, depot medroxyprogesterone acetate, had totally unpredictable patterns, with infrequent but prolonged bleeding/spotting episodes. The incidence of amenorrhea rose from just under 10% in their first injection interval to over 40% in their fourth. The methods of analysis recommended by WHO in 1985 still require substantial refinement. Nevertheless, they are more sensitive than those used previously for WHO trials and produce an easily understood, clinically meaningful characterization of bleeding patterns.     

Implanon use in Thai women above the age of 35 years

A prospective study of Implanon implant use in women older than 35 was conducted in Bangkok, Thailand. The purposes of this study were to evaluate the menstrual pattern and side effects of Implanon in 51 women followed for 6 months. Their mean age was 39.7 years. Most acceptors had completed primary school. No accidental pregnancies occurred in 6 months of use. The most common menstrual pattern in these acceptors was irregular bleeding followed by amenorrhea. The major side effect was irregular bleeding. There was no significant change in body weight, body mass index and diastolic blood pressure during the 6-month follow-up period, but systolic blood pressure declined. Implanon implant use is a safe and effective contraceptive method and should become another choice for contraception in women aged above 35 years who have contraindications for oral contraceptive use.     

Bleeding and spotting with the levonorgestrel 13.5 mg intrauterine system: the impact of insertion timing

ObjectiveTo assess the impact of early versus late menstrual cycle insertion on bleeding/spotting in the 90 days following levonorgestrel (LNG) 13.5 mg intrauterine system (IUS) insertion.Study designIn this observational study, participants received a LNG 13.5 mg IUS and provided 90 days of bleeding/spotting data by answering the following daily text: “Have you had no flow (0), spotting (1), or bleeding (2) today?” We dichotomized insertion timing as early (days 1–7 from last menstrual period) and late (remainder of menstrual cycle) and compared bleeding/spotting between the two groups in the 90- and 30-day reference periods. We used multivariate regression methods to study associations between cycle day at insertion, parity, historical bleeding, recent hormonal contraceptive use and bleeding/spotting.ResultsIn the 90-day dichotomous analysis (n=125), we found no differences in the number of days of bleeding/spotting, bleeding or spotting between the early and late insertion groups. In the 30-day dichotomous analysis (n=131), early insertion was associated with fewer days of bleeding than late insertion (5±3 vs. 7±4 days, p<.01). Recent hormonal contraceptive users experienced fewer days of bleeding than new users (5±4 vs. 7±3 days, p<.01). In the 90- and 30-day regression models, earlier insertion was associated with fewer days of bleeding (p=.02, p=.02). Recent contraceptive use was associated with fewer days of bleeding/spotting (90-day, p=.03) and fewer days of bleeding (30-day, p<.01). Nulliparity was associated with spotting (30-day, p=.04).ConclusionsEarly cycle insertion does not impact 90-day bleeding/spotting. Early cycle insertion and recent hormonal contraceptive use decrease 30-day bleeding.ImplicationsThe LNG 13.5 mg IUS may be inserted throughout the menstrual cycle with small differences in bleeding patterns in the 30 but not the 90 days following insertion. Shared decision making should determine timing of insertion.     

Efficacy and side effects of Norplant use in Thai women above the age of 35 years.

A prospective study of Norplant implant use in women aged above 35 years was conducted in Bangkok, Thailand. The purposes of this study were to evaluate the efficacy, menstrual patterns, and side effects of Norplant use in these women. A total of 100 women were recruited in a 1-year clinical study. Their mean age was 39.7 years. Most acceptors had completed secondary school. No accidental pregnancy occurred throughout the 1 year of use in this study. The most common menstrual pattern in these acceptors was amenorrhea followed by irregular bleeding. The major side effect was irregular bleeding. There was no significant change in systolic and diastolic blood pressure during the 1 year follow-up period. Thus, Norplant implant use in older women is a safe and effective contraceptive method. This should become another choice for contraception in women aged above 35 years who have contraindications for oral contraceptive use.     

国产皮下埋植避孕方法多中心研究

本研究在全国11个省100个分中心对国产Ⅰ型和Ⅱ型皮下埋植剂进行临床多中心比较研究,共接收合格对象19673例,目前已完成二年随访。二年随访率94.29％,累计继续使用率分别为88.89,％(Ⅰ型)和89.93％(Ⅱ型),Ⅱ型显著高于Ⅰ型,二年累积妊娠率Ⅰ型和Ⅱ型分别为每百妇女0.0462和0.281,其间呈显著性差异。Ⅰ型埋植剂无异位妊娠发生,Ⅱ型埋植剂发生异位妊娠3例,发生率为0.163/1000妇女年。副反应的发生率有随时间增长而减少的趋势。主要副反应为月经失调,占副反应的90％以上。月经异常中月经频发、不规则出血和点滴出血的发生率高于月经稀发/量少和闭经。闭经和月经稀发/量少的发生率Ⅰ型高于Ⅱ型。二年观察中,因月经问题而终止使用者占总终止人数的78％,与月经问题有关的二年累积终止率Ⅰ型为每百妇女8.96,Ⅱ型为7.84,差别有显著性。二年观察研究表明,两种国产皮下埋植剂的副反应发生率和避孕效果以及二年的续用率与Norplant相似。     

Effect of etonogestrel subdermal contraceptive implant (Implanon) on liver function tests -- a randomized comparative study with Norplant implants

OBJECTIVE: The study aimed to assess the possible differences in effects of Implanon and Norplant implants on liver function over 2 years of use. METHODS: This is a 2-year open randomized study of 80 implant (Implanon and Norplant) acceptors. Selected parameters of liver function were tested in the serum before implant insertion and at 6, 12 and 24 months after implant insertion. RESULTS: In both the implant groups, the mean total and unconjugated bilirubin and the gamma-glutaryl transferase levels were significantly raised during implant use. For none of the subjects, at any sampling period, did the levels exceed the normal range in our population. There was no significant elevation of any other liver enzymes in either group. CONCLUSION: It appears that there may be mild hepatocellular dysfunction associated with the use of both Implanon and Norplant, which is possibly of no clinical significance to the healthy acceptor.     

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.     

Phase II randomized comparative clinical trial of Norplant (six capsules) with Norplant-2 (two covered rods) subdermal implants for long-term contraception: report of a 24-month study. National Programme of Research in Human Reproduction

In a randomized clinical study, contraceptive efficacy and bleeding patterns were studied in a group of healthy, regularly menstruating, non-lactating women (n = 84) using two 4.4 cm covered silastic rods containing levonorgestrel, Norplant(R)-2, and compared with another group of women (n = 88) using six 3.4 cm capsules also containing levonorgestrel, Norplant(R). The silastic rods or capsules were placed subdermally in the medial aspect of the upper arm. No method failure was reported up to 24 months of use in this study with either of the device. The bleeding pattern was also similar for both devices as indicated by average episode length, number of bleeding runs and number of spotting days. The continuation rates with both devices were over 80 per 100 users at the end of 12 months and over 65 per 100 users at the end of 24 months. Discontinuations due to expulsion of the device, bleeding problems or personal reasons were few and similar for both devices. The results suggest that silastic-covered rods, Norplant(R)-2, which are comparatively easier to insert and remove and have similar clinical effect, could replace capsules, Norplant(R), as a long-term reversible subdermal contraceptive.     

A longitudinal study of changes in endometrial microvascular density in Norplant implant users.

This study aimed to investigate the effects of the subdermal levonorgestrel contraceptive implant Norplant on endometrial vascular density at different durations of exposure, and the relationship between endometrial histology, vascular density, and bleeding patterns. A prospective controlled trial of Norplant implant users compared endometrial vascular density in biopsies taken before and after Norplant implant insertion. A total of 34 women with regular menstrual cycles requesting long-term contraception were recruited at the Sydney Centre for Reproductive Health Research, Australia. A significant increase in mean endometrial microvascular density was observed from as early as 3 weeks after insertion of Norplant implants. Vascular density was increased from a control secretory phase value of 189.6 (7.0 vessels/mm2 (+/- SEM) to 253.80 +/- 7 vessels/mm2 at 2-13 weeks of Norplant implant exposure (t ratio = 2.08, p = 0.01) and 212.7 +/- 12.9 vessels/mm2 at 14-42 weeks of exposure (t ratio = 2.03, p = 0.02). In those with atrophic endometrium, or in whom myometrium and basalis only were found in biopsies (20 of 66, 30%), mean endometrial vascular density was increased at 273.1 +/- 16.1 vessels/mm2 compared with 210.9 +/- 11.7 vessels/mm2 in other histological groups (F ratio = 9.74, p = 0.0028). Bleeding and spotting in the previous 30 days were less common in those with this histological appearance at a mean of 4.95 days compared with 8.22 days. This is the first study to assess endometrial vascular density in the early months of Norplant implant use. The findings suggest that the endometrial vasculature is profoundly altered in the early months of Norplant implant exposure when bleeding problems are most common.     

Persistent vaginal bleeding in a patient with a broken Implanon

A 29-year-old woman with an Implanon contraceptive device in situ presented with persistent and prolonged vaginal bleeding. The implant had been inserted 2 years previously; the patient had been happy with it and had been mainly amenorrhoeic with the occasional light period. She was concerned that the implant had broken during a game of 'rough and tumble' with her son in August 2000. Since the trauma to her arm her bleeding pattern had changed, and she began bleeding heavily for 3 weeks every month. The rod was removed and found to be fractured halfway across its width. A new Implanon device was inserted and the bleeding settled.     

Unscheduled bleeding with continuous oral contraceptive pills: a comparison of progestin dose

BackgroundAlthough the use of continuous oral contraceptive pills (OCPs) eliminates scheduled uterine bleeding, unscheduled bleeding is common. The objective of this study was to determine whether progestin dose influences bleeding with use of continuous OCPs.Study DesignThis was a secondary data analysis of two other studies of continuous OCPs. Women were eligible if they were switching from a cyclic hormonal contraceptive to a continuous OCP. Women took a 20-mcg ethinyl estradiol (EE)/100-mcg levonorgestrel (LNG) pill or a 20-mcg EE/90-mcg LNG pill for 112 days. The number of bleeding/spotting days was compared between groups using a t test. Sample size was adequate to detect a difference of 8 days of bleeding/spotting over the 112 day study period (β=0.80, α=0.05).ResultsSixty-six subjects were enrolled, 33 in each group. There were no differences in baseline characteristic, missed OCPs or side effects. There were no differences in the mean number of bleeding/spotting days in the first 84 days of the study (90 mcg LNG mean 20.8 (SE 3.6) days versus 100 mcg LNG 17.8 (SE 2.3) days, p=.48), nor was there a difference in the time to amenorrhea (p=.35).ConclusionOur results do not support the use of one LNG dose over another to decrease the amount of unscheduled bleeding women experience when initiating a continuous OCP.     

狄波-普维拉长效避孕针在上海市育龄妇女中的应用

为验证每三个月注射一次的醋酸甲孕酮避孕针(狄波-普维拉),是否适于中国妇女应用,1995年10月起在上海市区(县)7家医院试用,共接纳451例,其中哺乳期208例,非哺乳对象243例,共使用3708妇女月,有效率100％,一年期因症停用率39％,因社会因素停用15.7％,早期副反应以滴血及少量不规则出血为主,后期闭经发生率上升,以90天为月经记录参照时期,第一至第四参照时期出血(滴血)过长,人数由65.8％降至23.3％,闭经人数由6.2％升至45.2％,未发生严重并发症;哺乳期或35岁以下妇女副反应发生率低于非哺乳或年龄≥35岁者(P<0.05),证明醋酸甲孕酮为高效、长效、安全、方便的避孕措施,尤其适宜于产后42天妇女使用,可减少产后早期及哺乳期人工流产,更适用于反复避孕失败的年轻妇女。     

Evaluation of a continuous regimen of levonorgestrel/ethinyl estradiol: phase 3 study results

OBJECTIVE: This study was conducted to evaluate the safety and efficacy of a continuous daily regimen of levonorgestrel (LNG) 90 microg/ethinyl estradiol (EE) 20 microg (continuous LNG/EE). METHODS: Healthy women aged 18-49 years with regular menstrual cycles for 3 months enrolled in this single-treatment open-label study and took one pill of LNG 90 microg/EE 20 microg daily for 12 months. RESULTS: For the 2134 subjects enrolled, the Pearl Index method failure was 1.26, and user failure was 0.34. While on Pill Pack 13, 58.7% of subjects reported amenorrhea and 79.0% reported absence of bleeding. Overall, the number of bleeding and spotting days per pill pack declined progressively. Adverse events and discontinuations were comparable to those reported for cyclic oral contraceptive (OC) regimens, except for higher rates in those related to uterine bleeding. CONCLUSIONS: Continuous LNG/EE demonstrated a good safety profile and efficacy similar to cyclic OCs. The regimen continuously inhibited menses, increased the incidence of amenorrhea over time and, except for a subset of women, decreased the number of bleeding and spotting days.     

Nonpalpable ultrasonographically not detectable Implanon rods can be localized by magnetic resonance imaging

Recently, the contraceptive implant Implanon has been introduced in several European countries. In comparison to the six-capsule preparation Norplant, the removal of this single-rod system should be associated with less complications. However, the removal of nonpalpable Implanon rods can be difficult because the implant is not always visible with ultrasound. The aim of this study was to find a radiologic method for the localization of Implanon implants that are nonpalpable and can not be detected by ultrasound. X-ray, ultrasound, computed tomography, and magnetic resonance imaging (MRI) were investigated as methods to localize Implanon in a pig chest preparation and in a woman with a nonpalpable implant. The implant in the woman could be localized unequivocally only by MRI. We conclude that MRI is the best method for the unequivocal localization of nonpalpable, ultrasonographically not detectable Implanon rods. To avoid unnecessary scar tissue formation, it may be appropriate to defer surgery for the removal until definitive localization.     

Implantable contraceptives for women: effectiveness, discontinuation rates, return of fertility, and outcome of pregnancies

Progestogen-only contraceptive implants are highly effective. In most studies, 5-year cumulative pregnancy rates are less than 1.5/100 women for Norplant and Norplant II. No study has yet reported any failures with Implanon. Weight over 70 kg and age at insertion under 25 years both increase the failure rate of Norplant and Norplant II; however, data are as yet lacking for Implanon. The effectiveness of other progestogen-only implants for which there are as yet few data are unlikely to be any different. Continuation rates are high compared with other hormonal methods and with the intrauterine device. In most cohorts at least 35% of women, and often many more, are still using Norplant by the end of 5 years. Rates vary according to a number of factors, including population studied, age, and parity. Menstrual disturbance is by far the most common reason for discontinuation, with headache, acne, weight gain, and desire for pregnancy accounting for other common reasons for implant removal. Fertility returns rapidly following implant removal, and pregnancy rates (76-100% 1 year after removal) are usually no different from those following discontinuation of any other contraceptive method. There is no increase in the risk of ectopic pregnancy, fetal malformation, or impaired infant health in pregnancies conceived either during implant use or after removal.