A five-year evaluation of NORPLANT II implants in China

Effectiveness, safety and acceptability of Sino-implant (II) during the first year of use: results from Kenya and Pakistan

BACKGROUND

Sino-implant (II) is a two-rod subcutaneous contraceptive implant used up to 4 years, containing 150 mg of levonorgestrel. We conducted two observational studies of Sino-implant (II) to evaluate its performance in routine service delivery settings.

METHODS

We enrolled 1326 women age 18-44 who had Sino-implant (II) inserted at clinics in Pakistan and Kenya. Women were followed-up using either an active or passive follow-up scheme in each study. Study outcomes were: one-year cumulative pregnancy and discontinuation rates; rates of insertion and removal complications; adverse event and side effect rates; reasons for discontinuation; and implant acceptability and satisfaction with clinic services.

RESULTS

A total of 754 women returned for at least one follow-up visit. The overall Pearl pregnancy rate was 0.4 per 100 woman-years [95% confidence interval (CI) 0.1, 0.9] resulting from 1 confirmed post-insertion pregnancy in Kenya and 4 in Pakistan. Country-specific Pearl rates were 0.2 (95% CI 0.0, 0.9) in Kenya and 0.6 (95% CI 0.2, 1.6) in Pakistan. The total cumulative 12-month probability of removal was 7.6% (95% CI 6.1, 9.1), with country-specific removal probabilities of 3.7% in Kenya (95% CI 2.1, 5.3) and 10.8% in Pakistan (95% CI 8.5, 13.2). Four serious adverse events occurred in Kenya and none occurred in Pakistan; one SAE (an ectopic pregnancy) was possibly related to Sino-implant (II). Most women in both countries said they would recommend the implant to others.

CONCLUSION

The results from these studies reveal high effectiveness and favorable safety and acceptability during the first year of use of Sino-implant.

IMPLICATION

The favorable Sino-implant (II) findings from Kenya and Pakistan provide further evidence from disparate regions that Sino-implant (II) is safe, effective and acceptable during routine service delivery.

Risks and benefits, advantages and disadvantages of levonorgestrel-releasing contraceptive implants

Levonorgestrel-releasing implants are long acting contraceptives, approved for 5 years of continuous use. Two marketed systems, the six capsule Norplant use of tradenames is for product identification purposes only and does not imply endorsement. and the two rod Jadelle, have essentially equal rates of drug release, pregnancy and adverse events over 5 years of use. Randomised clinical trials and controlled cohort observations indicate that for the first 3 years, when pregnancy rates are at or almost zero, no other contraceptive system is more effective, although etonogestrel implants provide equal effectiveness. Annual pregnancy rates rise in the fifth year of continuous use but remain below 1 per 100 women. Annual pregnancy rates of Norplant users remain below 1 per 100 throughout 7 years of continuous use. Levonorgestrel implants provide low progestogen doses; 40-50 microg/day at 1 year of use, decreasing to 25-30 microg/day in the fifth year. Serum levels of levonorgestrel at 5 years are 60-65% of those levels measured at 1 month of use. Adverse effects with levonorgestrel implants are similar to those observed with progestogen only and combined oral contraceptives. Risks of ectopic pregnancy, other pregnancy complications and pelvic inflammatory disease are reduced in comparison with those of women using copper or non-medicated intrauterine devices. Risks of developing gallbladder disease and hypertension or borderline hypertension, although small, are about 1.5 and 1.8 times greater, respectively, in women using levonorgestrel implants than in women not using hormonal contraception. Other serious diseases have not been found to occur significantly more frequently in levonorgestrel implant users than in women not using hormonal contraception. The great majority of levonorgestrel implant users experience menstrual problems, but serious bleeding problems are not more frequent than in controls. Other health problems reported more frequently by levonogestrel implant users than by women not using hormonal contraception in a study of 16000 women included skin conditions, headache, upper limb neuropathies, dizziness, nervousness, malaise, minor visual disturbances, respiratory conditions, arthropathies, weight change, anxiety and non-clinical depression. Clinical depression is not more frequent in women using implants compared with those not using hormonal contraception (i.e. using intrauterine devices, sterilisation). Removal problems occur less frequently with Jadelle than with Norplant. The mean removal time for Jadelle is half that of Norplant. Levonorgestrel implants in nationally representative scientific samples, in randomised trials, and in controlled cohort studies have continuation rates as high as or higher than any other reversible contraceptive over a duration of 5 years. This would imply that the satisfaction women derive from the contraceptive effectiveness of levonorgestrel implants greatly outweighs the dissatisfaction that may accompany menstrual disturbances and other adverse effects associated with implants.

Safety of implantable contraceptives for women: data from observational studies

Contraceptive implants are registered in over 60 countries and have been used by millions of women for three decades. This article reviews findings from observational studies on the safety of contraceptive implants and examines the risk of specific health outcomes. Fifty-five articles were reviewed, and the body of evidence for each health outcome was summarized. Available evidence suggests that contraceptive implants are safe and, overall, implant users do not experience adverse events at rates higher than women not using implants. With respect to specific outcomes, the evidence suggests no increased risks of pelvic inflammatory disease, decreased bone mineral density, anemia, thrombocytopenia, or death with implant use. The evidence was too limited to draw meaningful conclusions for neoplastic disease, cardiovascular events, and HIV/AIDS. Nonsignificantly elevated associations were reported for diabetes, serious mental disorders, and rheumatoid arthritis. Conditions for which risks were marginally, yet significantly, elevated were hypertension and gall bladder disease.

Users' perspectives on implantable contraceptives for women

Users of subdermal contraceptive implants report long duration of use, convenience, and high efficacy as liked features and bleeding irregularities, weight loss/gain, and headaches as disliked effects of these methods. Satisfied users tend to be women who do not experience side effects or women who value positive features and tolerate the side effects. Satisfaction of the users is also closely related to quality of services. Service delivery problems, such as lack of proper pre-insertion counseling, inadequacy in number and imbalance in the geographical distribution of providers who can insert and remove implants, and appropriately manage side effects have been observed in new programs. Insensitivity of some providers to side-effects, such as bleeding irregularities, and to requests for removal have caused user dissatisfaction and serious public concern. Care must be taken to provide implants in a context of high quality of care with adequate numbers and distribution of trained providers and a basic record-keeping and tracking system.

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%.

Implantable contraception

Although levonorgestrel contraceptive implants have been available for over 15 years, innovations have only recently led to a wider choice. These new implants offer easier insertion and removal and other advantages depending on the type of progestin. Implants prevent pregnancy by several mechanisms, including inhibition of ovulation and luteal function and alteration of cervical mucus and the endometrium. The high efficacy and ease of maintenance make implants an ideal contraceptive for many women, including adolescents, a population that uses implants infrequently but reports high satisfaction. Implants are appropriate for women who are breastfeeding, who have contraindications to estrogen, or who have diseases such as diabetes, hypertension, sickle cell anemia, or an HIV infection because implants have few metabolic or hematologic effects. Long-term use has not been associated with a decrease in BMD and generally leads to increased blood levels and iron stores. Women who wish to space their pregnancies appreciate the nearly immediate onset of action with insertion and the rapid termination of all effects with removal. All types of implants lead to menstrual changes and other side effects in some women. Adverse effects that occur in implant users more than the general population include headaches and acne. Women must be thoroughly counseled regarding the potential for menstrual alteration, side effects, and sexually transmitted infections if they do not use condoms. Despite their initial high cost, implants are a cost-effective method over several years, even when discontinued before the life of the implant.

The use of long-acting contraceptives in adolescents

DMPA and implants have played an important role in the attempt to prevent teenage pregnancies. Adolescent health care providers should provide continued counseling to girls using DMPA or implants and should promptly address any concern associated with these methods. Future studies are warranted to explore ways to prevent or reduce the side effects of DMPA and implants, as well as to develop new, optimal, long-acting contraceptives. Detailed baseline information should be obtained in every future study that explores the presence of side effects during the use of long-acting contraceptives.

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.

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).