Subdermal contraceptive implants

Early discontinuation of the IMPLANON® and associated factors in Ethiopia, systematic review and meta-analysis

Background

Implanon® is a commonly used effective long-acting reversible contraceptive method. It provides contraception for up to three years. Its early discontinuation was associated with an unwanted pregnancy, abortion, and socioeconomic burden. Thus, the main aim of this systematic review and meta-analysis is to determine the rate of early discontinuation of Implanon® and associated factors in Ethiopia.

Method

This Systematic review and meta-analysis was performed by using online databases including PubMed, Google Scholar, Cochrane, HINARI, Web of Science, and other gray and online repositories of Ethiopian Universities. The JOANNA Briggs Institute standard data extraction and appraising sheet format was used for the extraction of all included studies. To test the heterogeneity of the studies the Cochran Q test and I² statistics test were used. The Funnel plot and Egger's tests were used to detect possible publication biases of the included studies. The forest plots were used to present the finding of the overall prevalence of the early Implanon® discontinuation and the odds ratio (OR) along with a 95% CI.

Result

In this systematic review and meta-analysis seven studies with a total population of 3161 women using Implanon® were included. The overall pooled early Implanon® discontinuation rate was 31.34% (95%CI: 19.20, 43.47). Early discontinuation of Implanon® was associated with lack of counseling during service delivery 2.55times (OR: 2.55, 95%CI: 1.99, 3.25), the experienced side effect 3.25 times (OR: 3.25, 95%CI: 2.48, 4.24), absence of appointment after insertion 6.06 times (OR: 6.06, 95%CI: 2.15, 17.05), others decision on the women's choice 3.30 times (OR = 3.30, 95%CI: 2.52, 4.32), and lack the satisfaction of provided service 2.68 times (OR: 2.68, 96%CI: 1.61, 4.45).

Conclusion

About one-third of the women in Ethiopia discontinue the use of Implanon® within one year of the insertion. This is high compared to findings from other countries. Lack of counseling about the service, women's experience of the side effect, absence of the appointment following the service provision, other decisions on the method chosen, and lack of satisfaction were factors associated with the discontinuation of Implanon®. Hence, efforts should be made to reduce the rate of early discontinuation of Implanon® through drafting national guidelines and strategies accompanied by appropriate implementation, follow-up to foster adequate counseling, arrangement of appointments, helping women to decide on the choice, and increase the quality of care provision to enhance the satisfaction of the service.

Contraceptive Implants

Contraceptive implants or implantable contraceptive are five subdermal implants, rods the size of pencil lead that are embedded just under the skin on the inside of the upper arm. The rods contain etonogestrel, the metabolite of desogestrel, an equivalent progestin. Implants are often used during breastfeeding without an impact on milk production. It was identified that age does not affect the use of contraceptive implants but educational status is significant to its usage; there is an association between the age at first birth and the use of contraceptive implants; the number of liveborn children has a significant impact or influence on the use of implants; etc. This chapter focuses on types of contraceptive implants and its mechanism of action; global statistics on contraceptive implants; side effects; health benefits and positive characteristics of contraceptive implants; those who can and cannot use contraceptive implants; reasons women are not interested in contraceptive implants and factors influencing its usage.

Implants with Sensing Capabilities

Because of the aging human population and increased numbers of surgical procedures being performed, there is a growing number of biomedical devices being implanted each year. Although the benefits of implants are significant, there are risks to having foreign materials in the body that may lead to complications that may remain undetectable until a time at which the damage done becomes irreversible. To address this challenge, advances in implantable sensors may enable early detection of even minor changes in the implants or the surrounding tissues and provide early cues for intervention. Therefore, integrating sensors with implants will enable real-time monitoring and lead to improvements in implant function. Sensor integration has been mostly applied to cardiovascular, neural, and orthopedic implants, and advances in combined implant-sensor devices have been significant, yet there are needs still to be addressed. Sensor-integrating implants are still in their infancy; however, some have already made it to the clinic. With an interdisciplinary approach, these sensor-integrating devices will become more efficient, providing clear paths to clinical translation in the future.

Whole-exome sequencing reveals novel candidate single nucleotide variations for preventing adverse effects of levonorgestrel implantation

Aim: To identify novel genes associated with adverse effects of levonorgestrel (LNG) implants based on comparative whole-exome sequencing. Materials & methods: A cohort comprising 104 participants, including 52 controls and 52 women with LNG-related adverse effects, was recruited. Seven cases and eight controls were selected for whole-exome sequencing. We verified 13 single nucleotide variations (SNVs) related with integrin-mediated signaling pathway and cell proliferation using the MassARRAY platform. Results: Finally, we screened 49 cases and 52 controls for analyses. Two SNVs (rs7255721 and rs1042522) were located in ADAMTS10 and TP53, respectively, and significantly different between two groups. These two SNVs lead to changes in protein structure and physicochemical parameters. Conclusion: Here, we defined two pathogenic mutations related to adverse LNG effects.

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.

Implantable sandwich PHBHHx film for burst-free controlled delivery of thymopentin peptide

Sustained release and non-parental formulations of peptides and protein drugs are highly desirable because of enhanced therapeutic effects as well as improved patient compliance. This is especially true for small peptides such as thymopentin (TP5). To this end, implantable sandwich poly (hydroxybutyrate-co-hydroxyhexanoate) (PHBHHx) films were designed to prolong release time and to inhibit burst release phenomenon of TP5 by a simple volatilization method. In vitro release studies revealed that sandwich films had nearly no burst release. In vivo release time of sandwich films was prolonged to 42 days. Pharmacodynamic evaluation demonstrated that TP5 sandwich films significantly increased survival rates in a rat immunosuppressive model and normalized CD4⁺/CD8⁺ values. These results suggest that TP5 released from sandwich films can attenuate cyclophosphamide's immunosuppressive activity, and possibly achieve results comparable to daily TP5 injection therapy. Thus, sandwich PHBHHx films show excellent potential as a sustained, burst-free release system for small molecular weight, hydrophilic peptide drugs.

Innate Immunity and Biomaterials at the Nexus: Friends or Foes

Biomaterial implants are an established part of medical practice, encompassing a broad range of devices that widely differ in function and structural composition. However, one common property amongst biomaterials is the induction of the foreign body response: an acute sterile inflammatory reaction which overlaps with tissue vascularisation and remodelling and ultimately fibrotic encapsulation of the biomaterial to prevent further interaction with host tissue. Severity and clinical manifestation of the biomaterial-induced foreign body response are different for each biomaterial, with cases of incompatibility often associated with loss of function. However, unravelling the mechanisms that progress to the formation of the fibrotic capsule highlights the tightly intertwined nature of immunological responses to a seemingly noncanonical “antigen.” In this review, we detail the pathways associated with the foreign body response and describe possible mechanisms of immune involvement that can be targeted. We also discuss methods of modulating the immune response by altering the physiochemical surface properties of the biomaterial prior to implantation. Developments in these areas are reliant on reproducible and effective animal models and may allow a “combined” immunomodulatory approach of adapting surface properties of biomaterials, as well as treating key immune pathways to ultimately reduce the negative consequences of biomaterial implantation.

Impact of an implantable steroid contraceptive (etonogestrel-releasing implant) on quality of life and sexual function: a preliminary study

The aim of the study was to determine the impact of etonogestrel (ENG)-implant used for contraceptive purpose on Quality of life (QoL) and on sexual function (FSF) of healthy Italian women. The Female Sexual Function Index (FSFI) questionnaire and the Short Form-36 (SF-36) validated questionnaire were administered at baseline, 3 and 6 months after insertion of Nexplanon. The implant seems to have a positive impact on QoL after the first three months of therapy. Users showed an improved general health status and physical role status. The implant did not show negative effects on libido and on sexual function. In the first three months of treatment, users experienced a temporary reduction of vitality, mental health, social functioning and emotional role functioning, which seem to disappear after six months of therapy.

Hormonal contraception

Hormonal contraceptives have been a part of clinical practice for more than 40 years, and family planning programs, based largely on contraceptive provision, are regarded as one of the most successful public health interventions of the 20th century. Thus, discussion of family planning issues and contraceptive considerations has become an integral component of women's health care and one of the benchmarks of the traditional annual well-women visit. In terms of cost-effectiveness, prevention of unplanned pregnancies through contraceptive use has repeatedly been shown to be a highly cost-effective use of health care dollars. Options for effective hormonal contraception have expanded tremendously and include a variety of delivery options, including the pills both in traditional 21/7 format, and more recently in a 24/4 format, as well as a vaginal ring, a skin patch, implants, and the hormonally medicated intrauterine device. Importantly, the overall risks associated with hormonal contraceptives have been reduced as compared with older formulations, even for women with medical conditions. Many modern hormonal contraceptives also offer valuable noncontraceptive benefits. To help clinical decision making, a number of evidence-based guides have been published, and the American College of Obstetricians and Gynecologists has recently updated their practice bulletin on contraception use in women with medical conditions. In general, clinical protocols for provision of hormonal contraceptives have been streamlined, and unnecessary practices, tests, and procedures are identified and discouraged. In this review, we will summarize both technical and programmatic aspects of hormonal contraceptive use, and methods are discussed in order of efficacy from highest to lowest.

Contraceptive Implants: An Overview and Update

Contraceptive implants are safe, highly effective, and long-term methods of contraception that are widely applicable to any reproductive-aged woman. Implants require minimal user compliance and are cost-effective. The new single-rod system simplifies insertion and removal, making implants more accessible for both providers and patients. Specifically, progestin-only implants are safe options for various women including adolescents, postpartum, breast-feeding, those who are medically complicated, or those who have contraindications to or intolerance of estrogen-containing contraceptives.

[Ectopic pregnancy with etonogestrel contraceptive implant (Implanon): first case]

We describe the first case of ectopic pregnancy occurring in a patient with an etonogestrel contraceptive implant (Implanon). There was no factor predisposing to a failure of the technique (implant in place for less than 2 years and normal BMI). In addition there was no risk factor for an ectopic location of the pregnancy. We discuss the role of the micro progestative in the location of the pregnancy. This case report emphasizes the fact that ectopic pregnancy should not be ruled out in women taking this contraception, however efficient it is otherwise.

Optimisation of treatment by applying programmable rate-controlled drug delivery technology

A number of programmable rate-controlled drug delivery technologies have been developed during the last two decades with the aim of regulating the rate of drug delivery, sustaining the duration of therapeutic action and/or targeting the delivery of drug to a specific tissue. As a result, several therapeutically beneficial outcomes can be achieved, such as: (i) controlled delivery of a therapeutic dose at a desirable rate of delivery; (ii) maintenance of drug concentrations within an optimal therapeutic range for prolonged duration of treatment; (iii) maximisation of efficacy-dose relationship; (iv) reduction of adverse effects; (v) minimisation of the need for frequent dose intake; and (vi) enhancement of patient compliance. The treatment of illness can thus be optimised. To gain a better understanding of how to optimise the treatment of illnesses by applying programmable rate-controlled drug delivery technologies, this article reviews the scientific concepts and technical principles behind the development of various programmable rate-controlled drug delivery systems that have been marketed or are under active development. Finally, the roles of these technologies in optimising therapeutic outcomes in nine therapeutic areas are discussed.

Toxicology of progestogens of implantable contraceptives for women

There are currently four progestogens used in implantable contraceptives marketed or tested in clinical trials: levonorgestrel in Norplant and Jadelle, etonogestrel (3-keto-desogestrel) in Implanon, nestorone in Elcometrine, and nomegestrol acetate in Uniplant and Surplant. Each progestogen was evaluated for hormonal activity and for safety in a wide variety of tests in vitro and in animals prior to their use in women. All four progestogens underwent pre-clinical testing that generally followed the format for animal testing of steroidal contraceptives published by the World Health Organization and the US Food and Drug Administration (FDA). Most of the progestogens have been tested for genotoxicity in bacterial and mammalian cultured cells and in rodents. All were tested for toxicity in short- and long-term toxicology studies in rodents and dogs or monkeys, and all were tested for their effects on reproduction and fetal development. In most cases, the progestogens were tested for carcinogenicity in two rodent species, rats and mice. Early clinical trials in small numbers of women provided additional safety data prior to the exposure of large numbers of women in Phase 3 clinical trials. The published data and data submitted to the FDA demonstrate that the implantable progestogens have no significant or unusual toxicities and have a similar safety profile to the progestogens found in the approved oral contraceptives.

Endometrial effects of etonogestrel (Implanon) contraceptive implant

The subdermal contraceptive implant etonogestrel (Implanon; NV Organon International, Oss, The Netherlands) exerts complex effects on the endometrium. These include direct effects on the endometrium through endometrial progestin target sites, and indirect effects through suppression of the hypothalamic-pituitary-ovarian axis. The resulting effects are categorized by alterations in endometrial histology, endometrial thickness, dysmenorrhoea and menstrual bleeding pattern. The exact mechanism of action of progestins on the endometrium has not been determined. The contraceptive effect in Implanon users is mainly due to inhibition of ovulation. Current research is concentrating on the potential of the progestin implant to modify endometrial vascular, angiogenic, steroid receptor and proto-oncogene function. These processes may be involved in the causation of progestin-induced breakthrough bleeding.

Implanon: a critical review

OBJECTIVE

To evaluate clinical information on Implanon as a long-term method of contraception and, specifically, to review the efficacy and adverse effect profile of Implanon.

DATA SOURCES

A MEDLINE search (from 1966 through June 1999) was performed to retrieve primary and review articles. The search was limited to data on human subjects. Some references were identified through secondary sources.

STUDY SELECTION AND DATA EXTRACTION

Pharmacokinetic and pharmacodynamic studies, and clinical trials assessing the efficacy and safety of desogestrel implants were reviewed. Relevancy and consistency of information was assessed for each trial.

DATA SYNTHESIS

Implanon is the newest contraceptive implant system that has completed worldwide Phase III clinical trials. It is a single rod that contains a core of 68 mg of 3-keto-desogestrel with a membrane of ethylene vinyl acetate. Inhibition of ovulation occurs within one day of implantation, and effective contraception lasts for three years. Fertility returns within one month after implant removal. Insertion and removal by trained medical professionals is simple, and only minor complications have been documented. Adverse effects are mild and primarily consist of abnormal bleeding, weight gain, acne, breast pain, and headache.

CONCLUSIONS

The data on Implanon indicate that it provides effective long-term contraception with limited adverse effects. It appears to be a good addition to the currently available contraceptives.

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.

An integrated analysis of vaginal bleeding patterns in clinical trials of Implanon

The vaginal bleeding patterns observed during the use of the single-rod progestin-only implant, Implanon, compared with those seen during the use of the six-capsule implant, Norplant, have been analyzed. The acceptability of these bleeding patterns was also assessed. An integrated analysis of 13 different trials was done, studying reference periods (RP) of 90 days. These trials included totals of 1716 Implanon users and 689 Norplant users. There were statistically significant lower mean values over RP 2-8 the range over RP 2-8 is presented) for Implanon, for the number of bleeding-spotting days (15.9-19.3 vs 19.4-21.6; p = 0.0169), the number of bleeding days (7.5-10.0 vs. 11.7-13.1; p < 0.001), and the number of bleeding-spotting episodes (2.2-2.7 vs. 3.1-3.3; p < 0.0001). The bleeding patterns of Implanon users appeared to be more variable than those observed with Norplant: Implanon users had more amenorrhea, and slightly more infrequent bleeding, frequent bleeding, and prolonged bleeding than Norplant users. The difference was only statistically significant for amenorrhea (17.9%-24.8% with Implanon compared with 2.0%-7.0% for Norplant over RP 2-8). There were no statistically significant differences in the acceptability of the two products as indicated by the discontinuation rates, which were 30.2% and 0.9% in Europe and Southeast Asia, respectively, for Implanon, and 22.5% and 1.4%, respectively, in the two regions, for Norplant. The individual bleeding pattern was not predictable. However, in general, it can be stated that women initially without bleeding or with infrequent bleeding have only a small chance of becoming frequent bleeders, and vice versa. Dysmenorrhea clearly improved during use of both Implanon and Norplant. Neither Implanon nor Norplant caused anemia.

Pharmacokinetics of Implanon. An integrated analysis

The aims of this paper were to present data on the pharmacokinetics, clearance, bioavailability, and in vivo absorption of etonogestrel (ENG); to present the results of a longitudinal analysis of the plasma concentration-time curves of ENG; and to present the results of a cross-sectional analysis on the association of body weight with serum ENG concentrations. Implanon had an absorption rate of almost 60 micrograms/day after 3 months, which slowly decreased to 30 micrograms/day at the end of 2 years. The bioavailability over this period of time was constant and close to 100%. The clearance remained around 7.5 L/h. With a bioavailability and clearance that remained constant, it was concluded that accumulation of ENG does not occur. After Implanon insertion, serum concentrations increased within 8 h to concentrations associated with ovulation inhibition. Maximum mean serum concentrations (Cmax) amounted to 813 pg/mL and the time (tmax) to reach Cmax was 4 days. After reaching Cmax, ENG serum concentrations declined to about 196 pg/mL at the end of the first year, followed by a slow decline to 156 pg/mL at the end of the third year. After removal of Implanon, serum ENG concentrations declined to levels less than the detection limit of the assay (20 pg/mL) within 1 week. Lower body weight was associated with higher serum ENG concentrations.

A 4-year pilot study on the efficacy and safety of Implanon, a single-rod hormonal contraceptive implant, in healthy women in Thailand

OBJECTIVE

To investigate the contraceptive efficacy, safety and acceptability of a new single-rod, progestogen-only contraceptive implant (Implanon).

METHODS

In an open, non-comparative pilot study, 100 healthy women received a contraceptive implant containing the progestogen etonogestrel (3-ketodesogestrel) for 2 years with an optional extension up to 4 years.

RESULTS

Subjects were exposed to Implanon for 296.1 woman-years. There were no pregnancies during the study. Per 90-day reference period, the median number of bleeding-spotting days was 10 and the median number of bleeding-spotting episodes was 2. Amenorrhea occurred in 24-39% of subject during the first 2 years and in about 20% in those who continued in the 3rd and 4th years. The most common drug-related adverse event was headache (7%). A slight increase in body mass index was observed. Only a few subjects discontinued treatment early, due to bleeding irregularities (6%) or amenorrhea (1%). The cumulative discontinuation rates were 13.4% after 2 years, 25.3% after 3 years and 28.0% after 4 years of use. Within 3 months of implant removal, six normal pregnancies occurred, indicating a rapid return of fertility. The average time taken for insertion of the implant was 0.5 min, compared with 2.5 min for removal.

CONCLUSIONS

Implanon demonstrated excellent contraceptive efficacy and was well tolerated during up to 4 years of use. The vaginal bleeding pattern was variable and was characterized by relatively few bleeding events, but proved acceptable to most subjects. Because of its single-rod design, Implanon was quickly inserted and removed without complications.

Results of a user satisfaction study carried out in women using Uniplant contraceptive implant

A study of the acceptability of Uniplant, a 12-month single implant of nomegestrol acetate, included 819 women from Africa, Latin America, and China, participating in a clinical trial of Uniplant. A standard, pre-coded questionnaire was specially designed for this purpose and applied at the moment of removal of implant, either at the end of 12 months of use or at the time of discontinuation for whatever reason. The level of satisfaction proved high when users' comparison with their previous contraceptive method, users' recommendation of Uniplant to others, users' intention to use the method in the future, and service satisfaction were taken into consideration. Uniplant was considered easy to use, safe (low risk of pregnancy), and also to cause fewer side effects than other methods. When asked about the least liked feature of Uniplant, almost half the respondents said that there was nothing that they disliked and about one-third mentioned the changes in their menstrual pattern. However, according to the clinical trial, over half of the Uniplant users have bleeding patterns similar to untreated cycles. The majority of respondents did not feel any discomfort during the procedure of insertion and removal of the implant. About 70% of patients in the study stated that they required contraception for more than one year and most of these women said that they did not mind having to change the implant every year.

An enzyme immunoassay for serum and urinary levonorgestrel in human and non-human primates

A microtiter plate enzyme immunoassay (EIA) is reported for the measurement of levonorgestrel (LNG) in serum and urine samples of human and non-human primates, and the results are compared to data obtained by radioimmunoassay (RIA). Rabbit polyclonal antibodies were raised against the bovine serum albumin conjugate of the 3-O-carboxymethyl oxime (CMO) derivative of LNG. The enzyme label was produced by the conjugation of horseradish peroxidase to LNG at the 3-position by the same CMO bridge used for the immunogen. The assay requires 2.5 hours to perform using 2.2-azino-di-(3-ethylbenzthiazoline sulfonic acid) diammonium salt as the chromogenic substrate. Serum (100 microliters) is extracted with petroleum ether prior to assay, whereas urine samples (25 microliters) are diluted and measured directly. The sensitivity of the assay is 0.25 pg/well with a 50% displacement of label at 7.5-9.5 pg and a linear response through 250 pg/well. Minimum levels of 8.7 and 10.0 pg/ml can be detected in serum and urine samples, respectively. Changes in serum LNG concentrations were measured in women and non-human primates following LNG implantation or injection. In the non-human primate study, serum LNG concentrations began to rise rapidly following i.m. injection of LNG, with peak levels occurring on days 3 to 5, then decreasing to approximately 25-35% of peak levels for the duration of the study. Circulating concentrations of 1.86 +/- 0.18 ng/ml LNG were reached in women the first week post-insertion of Norplant implants and decreased by 50% at 7-10 days, 75% after 14-21 days, followed by a steady decrease during the next 60-70 days to constant low levels that exhibited a high individual variation. Correlation coefficients of EIA and RIA results were 0.988 for human serum, 0.926 for human urine, and 0.972 for non-human primate serum.