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.     

WHO 86925 Norplant上市后监测(中国部分)

本课题研究目的是对Norplant皮下埋植剂潜在副作用进行监测,以进一步证实其安全性。对使用Norplant和IUD或绝育术的妇女进行比较随访研究。每半年随访一次,详细记录所有健康情况,共随访5年。随访率达99.9％。结果:Norplant组及对照组IUD和绝育术的5年继续使用率分别为76.25、80.89、98.10/100使用者。Norplant的5年累计妊娠率为0.6/100使用者,远低于IUD的8.11/100使用者,宫外孕发生率为0.46/1000妇女年,低于IUD的1.24/1000妇女年,但宫外孕和妊娠之比在Norplant组为31.6:100,远高于IUD的6.7:100,如发生妊娠,要警惕宫外孕的可能。月经问题是Norplant的主要终止使用原因,但使用5年者,其血红蛋白均值上升,和接收时相比P<0.001,而IUD使用5年者,其血红蛋白均值下降,和接收时相比P<0.01。在观察5年中胆囊炎胆石症、纤维囊性乳腺病在Norplant使用者中的发病率高于对照组,P<0.05～0.001,但未发现重大健康问题。Norplant使用5年是安全的。     

Short-term response of bone turnover to low-dose oral contraceptives in exercising women with hypothalamic amenorrhea

BACKGROUND: We examined the response of bone turnover markers and indices of energy status after 2 weeks of oral contraceptive (OC) therapy in premenopausal women with exercise-associated menstrual disturbances (EAMD). STUDY DESIGN: Six women with EAMD received one 28-day cycle of a triphasic OC containing 180-250 mcg norgestimate/25 mcg ethinyl estradiol (EAMD+OC) and six were controls (EAMD controls). Bone turnover markers amino-terminal propeptide of Type I procollagen and serum carboxy-terminal telopeptides of Type I collagen (PINP and SCTX-I) were assessed at baseline and after 2 weeks of OC therapy (EAMD+OC) or after a 30-day monitoring period (EAMD controls). Total triiodothyronine, resting energy expenditure (REE) and dietary intake were assessed as secondary end points. The absolute and percent changes from baseline in the primary and secondary outcomes were evaluated using an analysis of covariance, adjusting for baseline values of the corresponding outcome. RESULTS: Compared to EAMD controls, a significant change from baseline was observed in the EAMD+OC group for PINP (mean+/-SEM, 9.9+/-6.1 vs. -33.9+/-9.0 mcg/L; p=.005) and SCTX-I (-0.02+/-0.11 vs. -0.25+/-0.07 ng/mL; p=.017), but not osteoprotegerin (-0.53+/-0.22 vs. 0.20+/-0.44 pmol/L; p=.429) after 2 weeks (14.7+/-0.3 days) of OC therapy. Total triiodothyronine levels were elevated in the EAMD+OC group after therapy compared with EAMD controls (19.7+/-4.1 vs. -8.4+/-4.9 ng/dL; p=.002); however, no differences between groups were observed for the changes in REE or dietary intake. CONCLUSION: Our data demonstrate that 2 weeks of low-dose OC therapy rapidly reduced markers of bone resorption and formation, without any significant impact on energy status in women with EAMD.     

Post-marketing surveillance of Norplant((R)) contraceptive implants: II. Non-reproductive health(1)

This controlled cohort study aimed to evaluate the safety and efficacy of Norplant contraceptive implants in developing countries. Women initiating Norplant implants were index subjects and women initiating intrauterine devices (IUDs) or surgical sterilization were controls. Consenting participants at 32 clinics in eight developing countries were admitted and followed-up every 6 months for 5 years. Major and less serious health events during follow-up were recorded. Incidence rate ratios of health events adjusted for clinic were estimated for initial and current method use. This paper reports non-reproductive health events. The study involved 7,977 women initiating use of Norplant, 6,625 of IUD, and 1,419 of sterilization. Five years follow-up was completed for 94.6% of the women. The study accumulated 78,323 woman-years of observation. The initial method chosen accounted for 84.4% or more of observed woman-years in users of Norplant, IUD, or sterilization. Twenty-two of the recorded 34 deaths were due to accidents, suicide or homicide. Few deaths or major health events were due to cancer or acute cardiovascular diseases and were not associated with the contraceptive method used. The incidence rates of major health events were low and with two exceptions, there was no significant excess risk of serious morbidity for Norplant users compared with controls; among Norplant initiators gallbladder disease occurred at an incidence rate of 1.5 per 1,000 woman-years and was weakly associated with use of Norplant (rate ratio 1.52 [95% C.I. 1.02, 2.27]). For current Norplant users compared to controls, the rate ratio of a combined variable of hypertension and borderline hypertension was significantly elevated (1.81, [1.12, 2.92]). The occurrence of less serious health events was also low and several of them were significantly more often reported among Norplant users. Headache-migraine, weight gain, mood disturbances, pruritus, eczema, and acne had incidence rates among Norplant users of 11.5, 4.5, 2.8, 1.5, 1.4, and 0.9 per 1,000 woman-years, respectively, and were significantly higher than in controls. Respiratory health problems, nonspecific symptoms, and several ill-defined conditions were also significantly more often reported for Norplant users, but some of the excess incidence may be attributable to reporting and detection bias. The study confirms the safety with respect to serious disease of Norplant, IUDs, and sterilization.     

Effects of the long-term use of depot medroxyprogesterone acetate as hormonal contraceptive on bone mineral density and biochemical markers of bone remodeling

PURPOSE AND METHOD: Our objective is to evaluate the effects of the long-term use of depot medroxyprogesterone acetate (DMPA) as a method of contraception on bone mineral density (BMD) and bone remodeling. Forty women (21-44 years old) who used DMPA for contraception for <1, 1-2 and >5 years, in addition to 20 age-matched healthy women (nonusers), participated in this study. Lumbar spine BMD (LS-BMD) was measured by dual-energy X-ray absorptionmetry. Serum osteocalcin (OC), a bone formation marker, was measured by enzyme amplification sorbent immunoassay. Urinary deoxypyridinoline (DPD), a bone resorption marker, was determined by enzyme immunoassay. RESULTS: Serum OC and urinary DPD levels in women who used DMPA for <1, 1-2 and >5 years were significantly increased compared to the corresponding levels in nonusers. The increase of both biomarkers was more pronounced with longer duration of use. LS-BMD was significantly decreased in women on long-term DMPA use compared to LS-BMD in nonusers. The mean percentage decrease of LS-BMD in women who used DMPA for 1-2 and >5 years was 9% and 11.8%, respectively. LS-BMD was negatively correlated with serum OC and urinary DPD in women who used DMPA. On the other hand, LS-BMD and bone turnover were not significantly different between women who used DMPA for <1 year and nonusers. CONCLUSION: Long-term use of DMPA (>2 years) had a significant adverse effect on BMD and induced increased bone turnover, as evidenced by a significant increase in biochemical indices of bone formation and resorption. The measurement of LS-BMD and of biomarkers of bone turnover may be recommended in women aged above 40 years and who used DMPA for a long duration (2-5 years).     

Post-marketing surveillance of Norplant contraceptive implants: I. Contraceptive efficacy and reproductive health

The subject of this study to examine the safety and contraceptive efficacy of Norplant, we undertook a 5-year study of follow-up of women initiating use of Norplant, intrauterine device (IUD) or sterilization in eight developing countries. Women attending family clinics were enrolled if they consented and were medically eligible to use Norplant, IUD, or female sterilization. Women who chose to initiate use of IUDs or surgical sterilization served as controls and were frequency matched in 5-year age-bands with women who chose to use Norplant. At admission women had a physical examination, and their medical histories, demographic, and socio-economic characteristics were recorded. Follow-up visits were scheduled in the first 6 weeks after admission and semi-annually thereafter for 5 years irrespective of change of contraceptive method. Incidence rate ratios of health events were estimated for initial and current contraceptive method use. This paper reports reproductive health events and contraceptive efficacy. Altogether, 7,977 women initiating use of Norplant, 6,625 of IUD, and 1,419 of surgical sterilization were admitted. Their mean ages at initiation were 28.5, 28.5, and 29.6 years, respectively. More than 99% were married or cohabiting, and parous. Five-year follow-up was completed by 94.6% of the women. By the end of 5 years, the mean duration of first segment use per initiator was 4.16 years for Norplant, 4.10 years for IUDs, and 4.96 years for sterilization accounting for 39,337 woman-years for Norplant, 31,915 for IUDs, and 7,071 for sterilization. The study accumulated 78,323 woman-years of observation. Pearl pregnancy rates for Norplant, copper IUDs and female sterilization were 0.27, 0.88, and 0.17 per 100 woman-years, respectively. Users of Norplant, copper IUDs, and sterilization had rates of ectopic pregnancy of 0.30, 0.68, and 0.13 per 1,000 woman-years, respectively. Major health events related to the reproductive system were rare. Rates of acute PID were significantly lower among Norplant users than IUD users (p = 0.004). The rate of ovarian enlargement was significantly higher in Norplant users than controls (p <0.001), but not rates of hospitalization for this condition. Vaginitis and vaginal discharge, and low abdominal pain were significantly less frequent in Norplant users than in the other groups. Bleeding disturbances were more frequent among Norplant users than controls but not anemia. The study confirms the high contraceptive efficacy of Norplant, copper IUDs, and female sterilization. The incidence rates of major reproductive health problems were low. There was no significant excess of serious reproductive morbidity among users of Norplant compared to users of IUDs and sterilization.     

长效避孕皮下埋植剂对生育妇女骨质的影响

为探讨长期缓释单孕激素对妇女骨代谢的影响,测定使用国产Ⅰ、Ⅱ型长效避孕皮下埋植剂和Norplant 3年以上妇女的骨密度及骨代谢指标。采用回顾、设对照组的研究方法,测定123例妇女骨密度(BMD)及其骨代谢指标血钙(Ca)、磷(P)、碱性磷酸酶(ALP)、骨钙素(BGP)、血清雌激素(E_2),尿钙(Ca)、尿肌肝(Cr)和尿羟脯氨酸(HYP)等。结果表明国产Ⅰ、Ⅱ型和Norplant组妇女骨峰值形成期(30～40岁)使用皮埋剂的三组妇女平均E_2水平有不同程度降低,但均在正常低限水平内,与对照组间无差别。除对照组外三组妇女平均E_2水平与BMD之间不呈线性关系;Norplant组妇女BMD和Ca/Cr、HTP/Cr的变化说明骨吸收过程增强。使用国产Ⅰ、Ⅱ型皮埋剂和Norplant妇女3年后平均E_2水平在正常低水平上波动,未造成BMD的变化及其它骨代谢指标的明显变化;三组皮埋剂妇女骨峰值形成期(30～40岁),骨密度处于正常水平范围。长效LNG缓释皮埋剂对育龄妇女在骨代谢方面是安全的。     

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

In order to assess efficacy, safety, and acceptability of the contraceptive subdermal implants Norplant^® and Norplant^®-II in Mexican women, a comparative phase III clinical trial was undertaken in eight clinics across the country. The study involved 1052 women who were followed-up trimonthly for three years. Cumulative pregnancy rates were 0.29% and 0.34% for Norplant and Norplant-II implants, respectively. Similar overall cumulative discontinuation rates were observed at three years: 50.38% for Norplant capsules, and 50.44% for Norplant-II rods. The main method-related reason for termination was endometrial bleeding irregularity which led to discontinuation rates of 11.94% and 11.62% for Norplant and Norplant-II contraceptive systems, respectively. In 15,279 woman-months of experience accumulated with Norplant implants and 14,092 with Norplant-II implants, there were few adverse events reported. No difference was found between the two groups in either difficulty for implants placement and removal or women's discomfort, even though the time required for insertion and removal of Norplant capsules was longer than for Norplant-II rods. It is concluded that during the first three years of use, both implants systems are equally effective, safe, and acceptable.     

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.     

Prolonged effectiveness of Norplant(R) capsule implants: a 7-year study

Soft tubing Norplant(R) contraceptive implants were studied in 1210 women for 7 years to measure the duration of effectiveness and the magnitude of the pregnancy rates over that time. Mean age at enrollment was 27.4 years. Of the enrollees, 42% were US residents. One-sixth (16.1%) weighed >/=70 kg at the time of implant placement. At the end of 5 years, the cumulative pregnancy rate was 1.1/100; at the end of 7 years, it was 1.9/100. No pregnancies occurred to any of the 400 women who enrolled in the study at age >/=30 years and who weighed <100 kg. Among women aged 18-33 years, the 7-year Norplant pregnancy rates are comparable to the median pregnancy rates of tubal sterilization methods for women of the same age and duration of use. For women aged >/=34 years, without regard to weight at admission, the 7-year effectiveness of soft tubing Norplant equals or surpasses that of tubal sterilization. For continuing implant users, annual pregnancy rates <1.0/100 in years 6 and 7, together with low cumulative pregnancy rates, testify that Norplant capsule implants remain highly effective for 7 years.     

Use of Norplant implants in a New York City clinic population

Two-hundred-eight women attending family planning clinics in New York City who received the Norplant contraceptive system during the first sixteen months of Norplant implants insertions were evaluated. Within this clinic population, Norplant implants were a popular contraceptive choice and were removed from 64 of the 208 recipients. Reasons for removal included bleeding, weight gain, and headache, and were consistent with those found in the clinical trials. Prior satisfaction with oral contraceptives did not predict success or failure with Norplant implants. The rate of follow-up visits to the family planning clinics was low. However, evidence exists that these women did not lose contact with the medical center and continued to receive health care.     

Progestin-only contraception prevents bone loss in postpartum breastfeeding women

BackgroundThere are an increase in bone loss during the first 6 months postpartum and a complete recovery postweaning. A few studies of steroid contraceptive use during this period provide some evidence towards protection of bone loss with progestin-only contraceptive methods.ObjectiveThe study was conducted to evaluate forearm bone mineral density (BMD) of breastfeeding postpartum women using nonhormonal and progestin-only contraceptive methods.Study DesignA prospective cohort study of postpartum women had an analysis performed at 6 months postpartum correlating BMD with contraceptive use. Forearm BMD was measured 7–10 days, 3 months and 6 months postpartum. Eighty-two women were analyzed, comparing nonhormonal (54) and progestin-only (28) contraceptive methods. Information about breastfeeding duration, amenorrhea and body mass index was collected.ResultsBaseline characteristics of the study population showed no statistical differences between the groups. The median duration of breastfeeding for both groups was 183 days. A significant BMD decrease was observed for the nonhormonal group (p<.001); however, no statistical difference was detected for the progestin-only group. Body mass index, BMD at 7–10 days postpartum and total duration of breastfeeding were positively correlated with BMD at 6 months.ConclusionsOur findings suggest a preventive effect towards postpartum bone loss with progestin-only contraception in breastfeeding women.     

Bone mineral density at various anatomic bone sites in women receiving combined oral contraceptives and depot-medroxyprogesterone acetate for contraception

The association between users of combined oral contraceptives and depot-medroxyprogesterone acetate (DMPA) for contraception and bone mineral density (BMD) has been controversial because of variations among studies. Like other studies, this cross-sectional study compares BMD in users of combined oral contraceptives and DMPA with that in nonusers. Unlike previous studies, we defined long-term use as >2 years, and we measured more bone sites than previous studies including lumbar spines, femurs, and forearms. The study group consisted of 59 women aged 30 years to 34 years who had been using combined oral contraceptives for 57.36 ± 27.02 months with a minimum period of 24 months, 34 women of the same age who had been using DMPA as contraceptive for 55.76 ± 35.31 months, and 62 women of the same age who had not used any steroid hormonal contraceptives for more than 6 months. BMD was measured by dual energy photon absorptiometer at lumbar spine 2–4, neck of femur, Ward’s triangle of femur, greater trochanter of femur, ultradistal radius, and distal ulnar, respectively. Age, body mass index, and lifestyles of both groups were matched with nonusers. Mean BMD at lumbar spine (L2–4) in the DMPA users was significantly lower than in the controls (1.031 ± 0.090 vs. 1.096 ± 0.116, P = 0.007). There were no significant differences in BMD values at bone sites other than lumbar spine between DMPA users and the controls. There were no significant differences in BMD values at all bone sites between combined oral contraceptives users and the controls. We conclude that combined oral contraceptives are not associated with changes in values of BMD, while DMPA is associated with decreased BMD only at lumbar spine. We comment that steroid hormonal contraceptives are safe to use for long-term contraception regarding bone mass effects.     

Enhanced metabolism of levonorgestrel during phenytoin treatment in a woman with Norplant implants

A 26-year-old woman, treated with phenytoin for 10 years because of epilepsy, had Norplant subdermal implants inserted after a legal abortion. She became pregnant again after nine months of Norplant use. Her plasma levonorgestrel (LNG) levels were followed during one month during phenytoin treatment and then later during one month after discontinuation of phenytoin. During phenytoin treatment, plasma LNG levels were markedly below the levels found in healthy women with Norplant. There was a pronounced, statistically significant increase in plasma LNG levels after discontinuation of phenytoin. The plasma levels of sex hormone binding globulin were markedly above those found in normal healthy women during treatment with phenytoin and decreased significantly after cessation of phenytoin. The effects on the pharmacokinetics of LNG were reflected by effects on the menstrual cycle. During phenytoin treatment, the woman had regular ovulatory menstrual cycles. After cessation of phenytoin, her cycles became irregular and during the study period of one month, no signs of ovulation were found. It is concluded that treatment with phenytoin during use of Norplant subdermal implants enhances the metabolism of LNG to an extent where the contraceptive efficacy is endangered.     

Norplant contraceptive implants: rods versus capsules

Norplant contraceptive implants are silastic implants containing levonorgestrel. When placed subcutaneously in the medial aspect of the upper arm, they release low levels of levonorgestrel in a constant manner over an extended period of time. Comparative studies of two silastic rods versus six capsules containing levonorgestrel were studied in 250 subjects for 4,464 months of use. Only one pregnancy occurred during the study. Side effect patterns were similar in both groups; the major side effect being irregular uterine bleeding. The bleeding, however, was well tolerated by subjects in both groups and discontinuation rate was very low. The two-rod system offers the advantages of easier insertion technique and shorter insertion time as well as ease of removal as compared to the six-capsule system. Norplant contraceptive implants offer a highly effective means of contraception which is particularly suited for women who are concerned about failure and compliance with oral contraceptives. This type of contraception should become well accepted, not only in underdeveloped countries, but in developed countries as well.     

NorplantR contraceptive subdermal implants: Two-year experience in Singapore

Norplant contraceptive implants are Silastic containing levonorgestrel implants. This study describes our two-year experience with 100 acceptors of Norplant implants in Singapore. No pregnancies occurred during the first two years of use. Desire for planned pregnancy and disruption of menstrual rhythm were the two main reasons for twenty implant removals during the two years. The continuation rate at the end of two years was 79%. The post-removal conception rate in women desiring pregnancy was 90% at the end of one year. It thus appears that the Norplant contraceptive system offers a highly effective, acceptable, reversible and safe method of contraception.     

A five-year clinical evaluation of NORPLANT contraceptive subdermal implants in Bangladeshi acceptors

A non-comparative study of the Norplant contraceptive subdermal implant system was conducted in Dhaka, Bangladesh. The study was designed to evaluate the contraceptive efficacy, safety and overall acceptability of Norplant implants. Six hundred women were enrolled in the clinical trial, which began in 1985 at three study sites. Follow-up visits were scheduled at 1, 3, and 6 months after Norplant implant insertion, and every six months thereafter until removal or at the end of five years. There were no post-insertion pregnancies during Norplant implant use in this study. After five years of Norplant implant use, there was no clinically significant change in body weight, systolic or diastolic blood pressure. Less than 3% of the women ever reported having any significant medical problems such as migraine, respiratory or cardiac problems during the study. The gross cumulative continuation rate was 41.2 per 100 women at the end of five years. The two most frequently reported reasons for discontinuation during the study were menstrual problems and desired pregnancy. Of the women who completed the five-year user satisfaction questionnaire, the majority of the women (86.3%) planned to continue using contraception after study completion. Of these women, approximately one-third said they planned to use another Norplant set. The findings presented suggest that the Norplant system is a highly effective, safe and acceptable method among Bangladeshi women.     

Androgen levels in women using Norplant implants

Plasma concentrations of sex hormone binding globulin (SHBG), testosterone, free testosterone, androstenedione (A4) and levonorgestrel were studied in 17 women before and during use of two levonorgestrel covered rods resulting in identical plasma concentrations of levonorgestrel as Norplant implants. There was a highly significant decrease in SHBG during treatment. Total testosterone and A4 also decreased significantly. Free testosterone remained unchanged. Diurnal variations were found to occur for A4, total and free testosterone, but not for SHBG or levonorgestrel. Moreover, plasma concentrations of testosterone, free testosterone, levonorgestrel and SHBG were measured in a second group of 88 women participating in a clinical study on Norplant implants, who at the one year follow-up visit either denied or claimed to have developed increased facial acne during treatment. There was no difference regarding SHBG, total testosterone, free testosterone or levonorgestrel between the groups of women with and without facial acne. However, the women in the group noticing increased acne during treatment, reported significantly more often to have had acne before treatment compared to the women who did not notice increased acne during treatment. It is concluded that treatment with Norplant implants does not result in increasing plasma levels of androgens.     

Norplant contraceptive implants: a new contraceptive for women

This article summarizes current knowledge on the mechanism of action, side effects, and effectiveness of Norplant contraceptive implants. The most common side effect of the implant method is its disruption of the menstrual cycle, especially in the 1st few months of use. Long intervals without frank bleeding may occur and be misinterpreted as pregnancy in women who have not been counseled about this possibility. The average annual continuation rate was 84/100 in a study of 324 women from several countries who were followed for 5 years after Norplant implantation. The net cumulative pregnancy rate for the 5-year study period was 0.6/100. Reasons for method termination included menstrual problems, other medical problems (headache, depression, fatique), planning pregnancy, and other personal reasons (change in marital status, change in residence). To provide training for doctors, nurses, and counselors, the Population Council has established a network of 5 training institutions. Within the next few years, drug regulatory agencies are expected to approve use of Norplant implants in many countries. Although at present the method is available only in Finland and Sweden, Thailand and Indonesia are considering the method and clinical trials are underway in India, China, Brazil, and the US. A consulting committee of the World Health Organization has concluded that Norplant implants are a suitable contraceptive method for use in family planning programs.     

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.