Phase III clinical trial with Norplant II (two covered rods): report on five years of use

Migration of Implanon

OBJECTIVE

To determine whether or not migration of the Implanon rod does occur if correctly positioned and, if indeed migration does occur, to measure the degree of such migration.

METHODS

A prospective study of 100 women who requested and had Implanon rods inserted by one fully trained health care professional holding the Faculty of Family Planning and Reproductive Health Care Letter of Competence in Subdermal Contraceptive Implant Techniques. Measurements were made from the insertion site to the distal end of the rods at 3 and 12 months post-insertion.

RESULTS

Of the 100 women studied, 95 were seen for follow-up at 3 months. There was no migration of Implanon in 58 (61%) patients. Of the remaining 37 (39%) patients where migration had occurred, 34 showed migration caudally and only three demonstrated cranial migration. With regard to the degree of migration, all but one case showed this to be less than 2 cm either cranially or caudally. At 1-year follow-up 87 patients were seen. No migration was noted in 39 (45%) patients. In the remaining 48 (55%) patients where migration had occurred, 44 showed migration caudally and only four demonstrated cranial migration, which in one case was over 2 cm. With regard to the degree of migration, all but one case showed this to be less than 2 cm either cranially or caudally. The measurement in the single case showing migration over 2 cm at 3 months remained the same at the 1-year follow-up.

CONCLUSIONS

These results show that up to 1 year after insertion of Implanon significant migration of the rod does not occur. The degree of migration noted in all cases except one was less than 2 cm. Where migration was noted, in the majority of cases this occurred caudally towards the insertion site. There were no cases of deep migration.

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.

Current status of fertility control methods in India

Approximately 48.2% of couples of 15 to 49 years of age practice family planning methods in India. Female sterilization accounts for 34.2%, with male sterilization declining from 3.4% in 1992-93 to 1.9% in 1998-99. Use of the condom increased to 3.1% from 2.4%. There is an urgent need for research to develop new contraceptive modalities especially for men and also for women and to make existing methods more safe, affordable and acceptable. Current efforts in India to develop a male contraceptive are mainly directed towards (i) development of antispermatogenic agents to suppress sperm production, (ii) prevention of sperm maturation, (iii) prevention of sperm transport through vas deferens or rendering these sperm infertile and (iv) prevention of sperm deposition. Research work in the field of prevention of sperm transport through vas deferens has made significant advances. Styrene maleic anhydride (SMA) disturbed the electrical charge of spermatozoa leading to acrosome rupture and consequent loss in fertilizing ability of sperm. A multicentre phase-III clinical trial using SMA is continuing and it is hoped that the SMA approach would be available in the near future as an indigenously developed injectable intra-vasal male contraceptive. The safety and efficacy of available oral contraceptives were evaluated. An indigenously developed oral contraceptive 'Centchorman', which is a nonsteroidal, weakly estrogenic but potently antiestrogenic, was found to be safe and effective and is now being marketed in India since 1991 as a 'once a week' pill. Cyclofem and Mesigyna have been recommended as injectable contraceptives with proper counselling and service delivery by Indian studies. It has been recommended that these injectable contraceptives be added to the existing range of contraceptive methods available in the National Family Planning Programme. Based on the Indian studies CuT 200 was also recommended. Studies have indicated the advantage of intrauterine devices (IUD); they are long acting, relatively easily removed and fertility returns rapidly after their removal. Recent studies have recommended CuT 200 for use up to 5 years. The combination of some plant products i.e. Embelia ribes, Borax and Piper longum has been found to be safe and effective as a female contraceptive and the results of phase-I clinical trials are encouraging. Research work is going on in the country in various areas with special reference to hormonal contraceptive - a three monthly injectable contraceptive, immuno-contraceptives, antiprogestins, etc.

Contraception with two levonorgestrel rod implants. A 5-year study in the United States and Dominican Republic

A 5-year trial of a two-rod contraceptive implant, which releases the progestin levonorgestrel (LNG rod), was conducted at four clinics with 594 women. Mean age and weight at admission were 25.5 years and 62.4 kg, respectively. Consent to continue through 5 years was sought and obtained when the 3-year cumulative pregnancy rate proved to be 0.8 per 100. No pregnancies occurred in the fourth or fifth years. The 5-year cumulative pregnancy rate was, therefore, 0.8 per 100 with an annual average pregnancy rate below 2 per 1000 women. Prolonged bleeding/spotting (8.2% of subjects) and irregular bleeding (5.6%) were the most frequently cited medical reasons for removal. Removals for headache (4.7%) and weight change (4.0%) were the next most frequent medical reasons. Between 1% and 2% of subjects during the 5-year trial sought removals for each of the following conditions: mood changes, lower abdominal pain, depression, or pain at the implant site. The mean annual continuation rate during the study was 77 per 100. Use per woman averaged 2.96 years. Mean removal time was 5.9 +/- 0.6 min. These data indicate that, for a 5-year period, the two LNG rod implants are equivalent to the six Norplant capsule implants with respect to safety and efficacy parameters, but permit easier and more rapid implant removal.

Experience of Thai women in Bangkok with Norplant-2 implants

A prospective study of the Norplant-2 contraceptive subdermal implant system was conducted in Bangkok, Thailand. The objective of the study was to evaluate the efficacy, adverse effects, and overall acceptability of Norplant-2 implants. A total of 140 women were enrolled in a 3-year clinical trial. The mean age was 29 years. Of all the acceptors, 70% had completed primary school. The continuation rates at years 1, 2, and 3 were, respectively, 94%, 89%, and 83%. No accidental pregnancies occurred throughout the 3 years of use in this study. Personal reasons were the leading cause for termination of Norplant-2 implant use. The 3-year cumulative termination rate for personal reasons was 7.2%. These personal reasons were divorce, husband having vasectomy, and moving away from the study area. The other leading cause for termination was medical reasons; acne, headache, and pain at the implant site were the complaints. The termination rate for medical reasons in year 3 of the study was 4.6%. Prolonged menstrual flow was the other main reason for termination. The 3-year cumulative termination rate for menstrual irregularities was 3.8%. In this study, the cumulative termination for planned pregnancy at the end of the year 3 was only 1.6%. The incidence of difficult removals was 8%. Breakage of the rods on removal was encountered in the majority of these cases. The study findings presented suggest that the Norplant-2 implants are highly effective with high continuation rates. The Norplant-2 system could become another choice of long acting reversible contraception for Thai women.

Norplant failure: an adolescent case study and review of the literature

STUDY OBJECTIVE

To alert clinicians to risk factors associated with levonorgestrel implant (Norplant; Wyeth-Ayerst Laboratories, Philadelphia, PA) failures in the adolescent population and discuss alternatives.

DATA SOURCES

Medline search of articles pertaining to the use of levonorgestrel implants in the adolescent population.

STUDY SELECTION

All articles pertaining to the use of levonorgestrel implants in adolescents.

CONCLUSIONS

Levonorgestrel subdermal implants, Norplant, have been successfully used worldwide as contraceptives. Clinical trials suggest that pregnancy rates while using levonorgestrel implants are positively correlated with increased body weight. In addition, pregnancy rates may be higher in women below age 25 years. Finally, patients who report regular menstrual cycles on levonorgestrel implants may be at greater risk for method failure. Consequently, despite its apparent success, levonorgestrel implants have some significant but little-known limitations that should be considered in initial adolescent patient selection, education, and postinsertion medical supervision.

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.

Levonorgestrel concentrations during use of levonorgestrel rod (LNG ROD) implants

In a three-year randomized trial that included 398 women, blood samples were collected for the purpose of assaying levonorgestrel concentrations in women using a new two-rod contraceptive implant system or an earlier implant formulation, Norplant-2 implants. Sample collection was at 1, 3, 6, 9, and 12 months after placement and semiannually thereafter through three years. Resulting assays and analyses showed that levonorgestrel concentrations of each implant formulation decreased significantly with time after placement, with increasing body weight, and with ponderal index. In the third year, several measures indicated that concentrations of the contraceptive drug were higher in women using the LNG ROD implants than in users of the original formulation. No pregnancies occurred among women in either group in the three years. This study provides evidence that the minimum levonorgestrel concentration needed to protect against pregnancy is below 200 pg/ml, and possibly is below 175 pg/ml.

Clinical performance of a new two-rod levonorgestrel contraceptive implant: a three-year randomized study with Norplant implants as controls

In a randomized three-year clinical trial at seven clinics, the performance of levonorgestrel rod (LNG ROD) implants used by 600 women was compared with that of soft tubing NORPLANT implants used by 598 women. No pregnancies occurred in either group of women and, accordingly, body weight did not affect the efficacy of either type of implant. There were neither statistically significant nor important differences in termination rates for any reason over the three years. Complaint and illness rates during use of either of the two implant types were statistically indistinguishable and were attributable to the same set of conditions. Seventy-one per 100 of the women using each implant regimen continued to the three-year point, for an average annual continuation rate of 89 per 100. Removals of LNG ROD implants were accomplished in about half the time required for removal of Norplant capsule implants (p < 0.001).

Menstrual bleeding patterns in Norplant-2 implant users

The objective of the present study was to analyze the patterns of menstrual bleeding in Singaporean women using Norplant-2 contraceptive implants over a five-year period. Of the 100 women recruited for the study, 62 were still using the implant at the end of five years. Only 9 women discontinued for menstrual reasons and they did so within the first 21 months of implant use. Although a normal menstrual bleeding pattern was uncommon during the first three months of use, 69.4% had normal menstruation at the end of five years. Irregular bleeding was the most common form of menstrual abnormality throughout the study period. Infrequent periods and amenorrhoea were distinctly uncommon, especially after the first two years of use. The pattern of bleeding with Norplant-2 was not significantly different from that previously observed with Norplant.

New hormonal methods of contraception

Three types of new contraceptive delivery system have been discussed in this chapter. Each have novel methods of delivery and may be acceptable to certain groups of women. It is clear that subdermal contraceptive implants are extremely useful as a long-term method of contraception, and provided insertion occurs correctly, removal will then be easy. The second-generation implants using a single rod, compared with the first-generation ones using six capsules, would appear to offer advantages both to the patient and in relation to the training of medical and paramedical personnel who have to fit the subdermal implant. The main disadvantage is the incidence of irregular bleeding, which, by and large, can be overcome by pre-insertion counselling and by time. The second method of delivery, vaginal rings, offers high patient acceptability, but a usable ring for contraception has as yet to be developed. Two approaches appear to be the use of a continuous progestogen-only ring, or a combined ring releasing oestrogen and progestogen with a 21-day-in, 7-day-out cycle of use. Ongoing studies will indicate whether vaginal lesions are significant or related to the flexibility of the ring. If these studies prove satisfactory, further development of the vaginal rings, both as an alternative method for interval use or as a specific postpartum form of contraception using progesterone-releasing rings, will be developed. Significant developments in the use of a combined monthly injectable have led to the release of two preparations, Cyclofem and Mesigyna, which are now available in many countries. This combined approach offers a significant reduction in amenorrhoea rates and unacceptable bleeding, the majority of women having acceptable menstrual patterns even during the first 3 months of use. All three methods have low and acceptable rates of pregnancy, the lowest being seen with the subdermal implants and with combined monthly injectables. Due to the length of action of subdermal implants, these may find a niche for women wishing to use a long-acting method and not wishing to be sterilized. They also provide a useful method where medical intervention is not available on a regular basis. Monthly injectable preparations can be given by paramedical personnel, and introductory studies have indicated that in developing and developed countries, they are highly acceptable. All three methods offer an increased choice for women and safe and effective methods of contraception.

Return of fertility following discontinuation of Norplant-II subdermal implants. ICMR Task Force on Hormonal Contraception

A total of 627 women who had discontinued the use of the Norplant-II implants for various reasons and were exposed to the risk of pregnancy were followed-up for two years for return of fertility. The cumulative conception rates in women who had discontinued due to planning pregnancy were 80.3 per 100 women at one year and 88.3 per 100 women at two years. The majority of women who did conceive (90 percent), had full-term normal live births; about 4 percent of women had spontaneous abortions, the remaining 6 percent decided on elective termination of pregnancy (ETP). The cumulative conception rates in women who discontinued due to bleeding irregularities and 'other reasons' were 64.5 and 55.8 per 100 women at one year and 77.9 and 75.1 per 100 women at two years, respectively. These rates were significantly lower as compared to those observed in women who discontinued due to planning pregnancy. A large proportion, about 40 percent, of women who conceived after discontinuation of the method due to bleeding irregularities and "other reasons," opted for ETP indicating that many women in these two groups did not desire another child and that such women need to be counselled for adopting another method of contraception. The spontaneous abortion rates observed in ex-users of Norplant-II implants (1.7 to 4.4% pregnancies) were comparable to the spontaneous abortion rates prior to Norplant-II implant use (3.6% pregnancies) indicating that ex-users of Norplant-II implants were not at a higher risk of spontaneous abortion.(ABSTRACT TRUNCATED AT 250 WORDS)

Vaginal bleeding patterns of women using different contraceptive methods (implants, injectables, IUDs, oral pills)--an Indian experience. An ICMR Task Force Study. Indian Council of Medical Research

Irregularity in vaginal bleeding patterns is the most common clinical side effect causing discontinuation of the method reported by the-users of the newer contraceptive methods, especially hormonal ones. An objective assessment of vaginal bleeding pattern is, therefore, critical in evaluation of a new contraceptive method for its acceptance and continued use. The menstrual diary records of women participating in clinical trials of several contraceptive methods undertaken by the Indian Council of Medical Research were analysed. It was observed that the long-acting progestogen-only hormonal contraceptives like levonorgestrel (LNG)-releasing subdermal implants Norplant or intrauterine devices (LNG-IUD) as well as injectable contraceptive NET-EN 200mg given 2 or 3 monthly produced disturbances in bleeding pattern in the majority of their users. Very heavy or prolonged bleeding, a potential health hazard was uncommon and a shift more towards infrequent bleeding was observed. In Norplant-II implants users, 75 to 80% of women had irregularities in bleeding pattern during the first year of use which improved with prolonged use. However, even at 4 years of use, about half of the users of Norplant-II implants continued to have irregular bleeding patterns. The bleeding disturbances occurred in 80% users of 200mg NET-EN injectable contraceptives also during first year of use, however unlike Norplant-II implants users, there was no improvement with prolonged use. Combined monthly injectable contraceptives containing 50mg NET-EN and 5mg estradiol valerate caused less bleeding problems with half of the users experiencing normal pattern during one year of its use. Combined low-dose oral pills, both triphasic and monophasic, produced much better cycle control as compared to any of the other hormonal contraceptive-treated groups; about 90% of combined oral pill users had normal bleeding patterns during one year of method use. The use of copper IUDs was associated with increased bleeding in 18 to 20% of women during the initial period of three months which improved with prolonged use. It was observed that the women having frequent or prolonged bleeding had discontinued the contraceptive method more often as compared to those having delayed bleeding episodes or oligomenorrhoea. However, discontinuation rates due to bleeding irregularities at one year were lower in Norplant-II implants users as compared to other long acting hormonal contraceptive methods such as injectables or IUDs in spite of similar or better bleeding patterns in women using these methods.(ABSTRACT TRUNCATED AT 400 WORDS)

A five-year evaluation of NORPLANT II implants in China

A five-year study of NORPLANT II rod implants was undertaken in four large cities and metropolitan areas in eastern China. Designed to test the safety, efficacy and acceptability of these implants, the study involved 1,208 women and was conducted concurrently with a similar study of NORPLANT capsule implants. At the end of five years, the gross pregnancy rate was 0.65 per 100, and the continuation rate was 65.3 per 100. Both these values were similar to and not statistically different from the rates of the capsule implant users. In 4,828 woman-years of use, there were few severe adverse events reported. Users and providers found the method to be an acceptable long-term contraceptive method of great reliability.