Norplant subdermal contraceptive system: experience in Taiwan

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.

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.

Norplant: reasons for discontinuation and side-effects

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

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.

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

OBJECTIVES

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

METHOD

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

RESULTS

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

CONCLUSION

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

Efficacy and continuation rates of Norplant in Pakistan

A total of 265 women who had the Norplant system inserted were followed for 5 years. The present study is based on 11,435 women-months of use, describing the continuation rates and efficacy of Norplant among these women. The 5-year cumulative continuation rate was 45.7 per 100 continuing users. The continuation rates were age-dependent. The women > or = 35 years of age consistently maintained higher continuation rates at all time intervals as compared with those of younger women. During 5 years of follow-up, five women became pregnant. Three pregnancies occurred in year 2, one in year 3, and one in year 5. The 5-year cumulative pregnancy rate was 2.5 per 100 continuing users. The weight of the user did not influence the pregnancy rate. The continuation rates, as well as the pregnancy rates, are comparable to those reported from other countries in the region.