Hormonal implants: contraception for a new century

Safety and Benefits of Contraceptives Implants: A Systematic Review

Progestin-only contraceptive implants provide long-acting, highly effective reversible contraception. We searched the medical publications in PubMed, CENTRAL, and EMBASE for relevant articles on hormonal implants published in English between 1990 and 2021. Levonorgestrel (LNG) 6-capsule subdermal implants represented the first effective system approved for reversible contraception. The etonogestrel (ENG) single rod dispositive has been widely employed in clinical practice, since it is a highly effective and safe contraceptive method. Abnormal menstrual bleeding is a common ENG side effect, representing the main reason for its premature discontinuation. Emerging evidence demonstrated that it is possible to extend the use of the ENG implant beyond the three-year period for which it is approved. The ENG implant could be an effective and discrete alternative to the IUD in young girls, such as post-partum/post-abortion. Implants should be inserted by trained skilled clinicians who previously provide adequate counselling about their contraceptive effect, benefits, and any possible adverse events. More studies are needed to validate the extended use of the ENG implant for up to 5 years.

Contraceptive Implant Migration and Removal by Interventional Radiology

As the reversible contraceptive arm implants grow more popular, there is an increasing need to recognize the complications resulting from implant migration and removal. This review summarizes the findings of imaging and removal methods. When an implant is lost, the axillary region should be investigated first. If the implant still cannot be found, visualization though different methods have been employed for non-radiopaque implants. Real-time fluoroscopic-guided localization and removal can be accomplished for radiopaque Nexplanon. Once the implant has been located, standard removal method and other modified techniques can be used to safely remove the implant depending on the implant's location.

Bioavailability of phytochemicals and its enhancement by drug delivery systems

Issues of poor oral bioavailability of cancer chemopreventives have hindered progress in cancer prevention. Novel delivery systems that modulate the pharmacokinetics of existing drugs, such as nanoparticles, cyclodextrins, niosomes, liposomes and implants, could be used to enhance the delivery of chemopreventive agents to target sites. The development of new approaches in prevention and treatment of cancer could encompass new delivery systems for approved and newly investigated compounds. In this review, we discuss some of the delivery approaches that have already made an impact by either delivering a drug to target tissue or increasing its bioavailability by many fold.

Controlled-release systemic delivery - a new concept in cancer chemoprevention

Many chemopreventive agents have encountered bioavailability issues in pre-clinical/clinical studies despite high oral doses. We report here a new concept utilizing polycaprolactone implants embedded with test compounds to obtain controlled systemic delivery, circumventing oral bioavailability issues and reducing the total administered dose. Compounds were released from the implants in vitro dose dependently and for long durations (months), which correlated with in vivo release. Polymeric implants of curcumin significantly inhibited tissue DNA adducts following the treatment of rats with benzo[a]pyrene, with the total administered dose being substantially lower than typical oral doses. A comparison of bioavailability of curcumin given by implants showed significantly higher levels of curcumin in the plasma, liver and brain 30 days after treatment compared with the dietary route. Withaferin A implants resulted in a nearly 60% inhibition of lung cancer A549 cell xenografts, but no inhibition occurred when the same total dose was administered intraperitoneally. More than 15 phytochemicals have been tested successfully by this formulation. Together, our data indicate that this novel implant-delivery system circumvents oral bioavailability issues, provides continuous delivery for long durations and lowers the total administered dose, eliciting both chemopreventive/chemotherapeutic activities. This would also allow the assessment of activity of minor constituents and synthetic metabolites, which otherwise remain uninvestigated in vivo.

Ultrasound-guided removal of Implanon devices

Our study has shown that ultrasound-guided localisation and removal of Implanon rods is safe, practical and highly successful. Over a 4-year period, 119 patients had successful, uncomplicated removal of their subdermal devices.The technique is particularly useful for removal of the device when it is not palpable or when an attempt at removal of a palpable device has not been successful.

Long-term evaluation of lipid profile and oral glucose tolerance test in Norplant® users

PURPOSE

This study reports the results of the lipid profile and oral glucose tolerance test (OGTT) in 46 normal patients tested before and after 5 years of Norplant use.

RESULTS

After 5 years, there was a substantial decrease of 28.9% in high-density lipoprotein cholesterol levels and a similar but less pronounced fall of 7.1% in the total cholesterol levels. The Castelli 1 index did not vary, and the triglycerides and low-density lipoprotein cholesterol levels remained normal and unchanged throughout the study period. All the mean values of OGTT were significantly lower after 5 years, except for the 90-min glycemia.

CONCLUSION

These findings indicate that long-term Norplant use does not increase cardiovascular risks.

Contraception during perimenopause

Perimenopause marks the transition from normal ovulation to anovulation and ultimately to permanent loss of ovarian function. Fecundity, the average monthly probability of conception, declines by half as early as the mid-forties, however women during the perimenopause still need effective contraception. Issues arising at this period such as menstrual cycle abnormalities, vasomotor instability, the need for osteoporosis and cardiovascular disease prevention, as well as the increased risk of gynecological cancer, should be taken into consideration before the initiation of a specific method of contraception. Various contraceptive options may be offered to perimenopausal women, including oral contraceptives, tubal ligation, intrauterine devices, barrier methods, hormonal injectables and implants. Recently, new methods of contraception have been introduced presenting high efficacy rates and minor side-effects, such as the monthly injectable system, the contraceptive vaginal ring and the transdermal contraceptive system. However, these new methods have to be further tested in perimenopausal women, and more definite data are required to confirm their advantages as effective contraceptive alternatives in this specific age group. The use of the various contraceptive methods during perimenopause holds special benefits and risks that should be carefully balanced, after a thorough consultation and according to each woman's contraceptive needs.

Norplant use among urban minority women in the United States

The aim of this study was to develop a profile of urban American women who chose Norplant(R), determine factors associated with retention and early termination of implants, and to determine reasons for early removal. A total of 197 adult black and Hispanic women who had Norplant inserted were followed prospectively for up to 5 years. Interval and cumulative termination rates were calculated. Data were stratified by race and analyzed to include lost-to-follow-up (LTFU) subjects. Multivariate survival analysis was used to determine variables independently associated with termination. Cumulative continuation rates were 68% after year 1 and 13% after year 4. Significant predictors of retention included black race and lower parity. Probability of early termination increased with higher parity and Hispanic race. For black subjects, recent use of hormonal contraception was a predictor of retention. Menstrual changes and weight concerns were common reasons for removal. The Norplant 1-year continuation rate is lower than previously reported, but is higher than reported for oral contraceptives and Depo-Provera(R). Future studies should stratify by age, race, and parity, and use standardized terminology to report intervals of use.

Pregnancy in the adolescent patient. Screening, diagnosis, and initial management

Despite declines in adolescent pregnancy rates in the past decade, unplanned pregnancies among adolescents remain a significant problem in the United States. Clinicians caring for adolescents can be certain to encounter pregnancy in their patients. This article addresses surveillance and diagnosis for pregnancy in the adolescent, management, and referral of the newly-diagnosed pregnant adolescent, early pregnancy complications, common medical conditions affecting pregnancy in adolescents, and management of the postpartum and postabortal adolescent.

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.

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.

Efficacy and effects of short- and medium-term contraception in the common marmoset (Callithrix jacchus) using melengestrol acetate implants

This study examines the effect of melengestrol acetate (MGA) implants on reproductive function and various biochemical parameters, ovarian activity, and uterine morphology in ten female common marmosets implanted for either 6-8 or 19-21 months. Measures of body weight, concentrations of urinary glucose and blood liver enzymes were taken. Ovarian activity was assessed by analysis of urinary progestin levels and ultrasound examinations of the ovaries. Ultrasonography was also used to evaluate uterine morphology. MGA was highly effective in preventing pregnancies in the study animals. No changes in biochemical parameters were found; however, seven females developed a substantial weight gain during the study. Follicular development was not suppressed, as indicated by the presence of antral follicles, luteinized structures, and elevated urinary progestin levels. The uteri of the MGA-treated subjects were moderately enlarged with a thickened endometrium that showed a marked change in structural appearance indicative of hypertrophy and decidualization. After implant removal these changes quickly disappeared and all females ovulated within 3 weeks and conceived within 4 months post-treatment. MGA appears to be an acceptable contraceptive in the marmoset, although non-steroidal methods should be evaluated as possible potential alternatives.

A comparative analysis of three methods of contraception: Effects on blood glucose and serum lipid profiles

BACKGROUND

Hormonal contraceptives are one of the major means of family planning, yet their use is not without side effects. In this study, we have tried to assess some of the metabolic effects of three hormonal contraceptives commonly used by young females.

PATIENTS AND METHODS

Three hundred young, healthy, nonsmoking and normotensive women of childbearing age who were seeking contraceptive advice were randomly allocated to one of the three groups receiving ethinyl estradiol and norgestrel (group 1), medroxyprogesterone acetate (group 2), and levonorgestrel capsules (group 3). Levels of fasting blood glucose (FBG), total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C), were measured prior to the initiation of therapy and after termination of the study (6 months).

RESULTS

There was no significant difference between the three groups as far as the mean age, height and weight were concerned. FBG increased in all three groups, but the difference in the rate of increase was not statistically significant (P=0.29). Total cholesterol, TG and LDL-C increased, while HDL-C level decreased in groups 1 and 2. These changes were, however, more profound in the group 2 cases. In those receiving levonorgestrel, all lipid parameters decreased. The amount of change for the total cholesterol and triglyceride was quite significant (P<0.001), while the reduction in HDL-C was not significantly different from the other two groups by pairwise comparisons (Tukey-HSD procedure). The LDL-C/HDL-C ratio was found to be significantly increased in groups 1 and 2, but it remained almost unchanged in the group 3 cases (P<0.001).

CONCLUSION

Because of these favorable biochemical findings, we believe that levonorgestrel should be the contraceptive drug of choice for women of childbearing age who are seeking a safe method of contraception.

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.

Ultrasound characteristics of subdermally implanted Implanon contraceptive rods

This study was designed to define sonographic characteristics and the optimal sonographic technique for localization of the single rod Implanon system. Diagnostic ultrasonography was performed in eight women who had the Implanon rod implanted in the medial aspect of the upper arm. All implants were scanned in the longitudinal and transverse direction using 3.5 MHz, 5 MHz, and 7.5 MHz linear array transducers. Scanning was performed both directly against the skin and with 2 and 4 cm Kiteco ultrasound stand-off pads. Each image obtained was evaluated for detectability of the Implanon rod and the grade of acoustic shadowing produced by the Implanon rod by two independent observers. Discrepancies in evaluation were adjudicated by a third observer. The Implanon rod implant was not directly identified using the transducer and standoff pad combinations. Implanon rods were indirectly identified as a result of the posterior acoustic shadow cast by the Implanon. Best demonstration was achieved with the 5 or 7.5 MHz transducer and a 2 cm stand-off pad in the transverse direction. Appropriate ultrasonographic technique and familiarity with posterior acoustic shadowing patterns generated by the implant provide a noninvasive method for localization of nonpalpable, single rod implants prior to removal.

Contraceptive outcomes among adolescents prescribed Norplant implants versus oral contraceptives after one year of use

OBJECTIVE

Our goal was to evaluate both the continuation and pregnancy rates and the side effects experienced during the first year of use by adolescents who selected Norplant implants as compared with those who chose oral contraceptives for contraception. Furthermore, side effects experienced at 6 versus 12 months among Norplant implant users were compared to determine whether they diminished with continued use of this method.

STUDY DESIGN

We conducted a case-control study of 56 adolescents < or = 18 years old who selected implants as compared with 56 age-matched controls who chose oral contraceptive pills during the same time period.

RESULTS

Only 34% of patients prescribed oral contraceptives as compared with 91% of Norplant implant patients were still using their chosen method 1 year later. As a result 25% of oral contraceptive users became pregnant within 12 months as compared with none who selected Norplant implants. Side effects were reported by > 80% of patients in both groups, with menstrual irregularities reported more often by Norplant implant users than by oral contraceptive users (73% vs 5%, p = 0.01). Furthermore, Norplant implant users gained more weight than oral contraceptive users (8.7 vs 4.2 pounds) and were twice as likely to have an abnormal Papanicolaou smear. Finally, little diminution in side effects was observed during the second 6 months of Norplant implant use.

CONCLUSIONS

These data confirm that Norplant implants provide better protection against unintended pregnancy in an adolescent population but may be associated with more side effects. Clinicians should be aware of these findings so they can adequately counsel young patients about these two methods of contraception.

Changes in the menstrual bleeding of users of a subdermal contraceptive implant of nomegestrol acetate (Uniplant) do not influence sexual frequency, sexual desire, or sexual enjoyment

OBJECTIVE

To evaluate the effect of menstrual changes induced by a nomegestrol acetate subdermal contraceptive implant (Uniplant; Thermex, Bahia, Brazil) on users' sexuality.

DESIGN

Prospective observational survey.

SETTING

San Borja-Arriarán Hospital, University of Chile, School of Medicine.

PATIENT(S)

Normally cycling healthy women and their partners.

INTERVENTION(S)

Structured interview before and during use of the contraceptive.

MAIN OUTCOMES MEASURE(S)

Sexual frequency, desire, and enjoyment; perception of health; and contraceptive satisfaction.

RESULT(S)

During the use of the implant more women reported irregular cycles (32% versus 11%) and vaginal spotting (38% versus 19%). Frequency of sexual relations was unchanged (2.3 versus 2.5/wk) but the percent of couples engaging in sexual relations during vaginal spotting increased (28% versus 11%). There was no significant difference in the percent of men or women who reported an increase, or decrease, in perceived sexual desire, sexual enjoyment, or perception of health during the use of Uniplant.

CONCLUSION(S)

Despite the alterations in menstrual cyclicity and the occurrence of spotting, the use of a contraceptive subdermal implant of nomegestrol acetate did not effect desire for, enjoyment of, or frequency of sexual relations in users.

Norplant subdermal contraceptive system: experience in Taiwan

From November 1988 to December 1994, a total of 567 female volunteers were enrolled in Norplant implant studies at the National Taiwan University Hospital. After a median follow-up of 29 months, only 3 of the 529 available cases became pregnant (a cumulative rate of 1.2 pregnancies per 100 users over 5 years). Chromosome analysis of 2 of the 3 abortuses revealed 46,XX/46,XX,inv(3) and 46,XX. Menstrual problems were the most common adverse effects and were also the main reason for discontinuation (65%, 108/166). The continuation rate was 90%, 78%, 70%, 61%, and 42% at the end of 1, 2, 3, 4, and 5 years after insertion, respectively. In the 21 patients who wished to become pregnant, fertility recurred soon after removal of the Norplant implants. The data suggested that the Norplant implants system is a highly effective, safe, and long-acting method of reversible contraception. It would be worthwhile to introduce this contraceptive system to Taiwan's family planning program.

Serum concentrations of estradiol, progesterone, and levonorgestrel are not determinants of endometrial histology or abnormal bleeding in long-term Norplant implant users

The objective of this study was to determine the relevance of serum estradiol, progesterone and levonorgestrel concentrations to endometrial histology and uterine bleeding associated with long-term Norplant implants use. Eighteen five-year users of Norplant implants had endometrial biopsies and determinations of serum estradiol, progesterone and levonorgestrel concentrations. Correlations among these factors and uterine bleeding were calculated. Proliferative endometrium (but not sex steroid levels) was associated with abnormal bleeding. Neither ovarian steroid nor levonorgestrel concentrations was a predictor of abnormal bleeding. Hyperplastic changes were not seen even with high estradiol and low levonorgestrel levels.

Characteristics and experiences of American women electing for early removal of contraceptive implants

The study describes the experiences of 430 women who had Norplant(R) contraceptive implants removed prior to the five years of method effectiveness. Each subject was surveyed when the implants were inserted and again at the time of removal. Descriptive data are presented concerning perceptions of the method before insertion and after removal, reactions to the contraceptive and experiences associated with the removal procedure. Subjects' use of Norplant implants ranged from 14 days to 40 months, with a mean of 13.3 and median of 13 months. Over 95% reported changes in menstrual bleeding patterns and 95% experienced other non-bleeding related side effects. Non-bleeding side effects were the most frequently indicated reasons for removal, followed by bleeding changes. The mean removal time was 34 minutes with a median of 25 minutes. Over 48% reported experiencing significant pain during the removal procedure, and 27% stated that the pain was greater than expected. Despite electing for early removal of implants,the majority of women surveyed indicated satisfaction with all aspects of the method save its effect on their overall health. Although method-related side effects were intolerable for most subjects, their overall perception of the method was generally satisfactory.