Endometrial effects of etonogestrel (Implanon) contraceptive implant

Perspective Chapter: Modern Birth Control Methods

This chapter focuses on various modern birth control methods, including combined oral contraceptives, progestogen-only pills, progestogen-only injectables, progestogen-only implants, intrauterine devices, barrier contraceptives, and emergency contraceptive pills. Each contraceptive method is covered in detail, including mechanism of action, effectiveness, health benefits, advantages, disadvantages, risks, and side-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.

Effects of Etonogestrel implants on pelvic pain and menstrual flow in women suffering from adenomyosis or endometriosis: Results from a prospective, observational study

Adenomyosis and endometriosis are common causes of pelvic pain in women of reproductive age. Furthermore, adenomyosis is a major cause of menorrhagia. This study aimed to evaluate the effects of Etonogestrel implants on pelvic pain and menstrual flow in women requiring long-acting reversible contraception and suffering from adenomyosis or endometriosis.One hundred women with adenomyosis or endometriosis and asking for contraception with Etonogestrel implants were enrolled in this study and were followed-up for 24 months. Patients were interviewed on pelvic pain by visual analog scale (VAS) pain score, menstrual flow by the number of sanitary napkins, menstrual bleeding pattern, weight gain, breast pain, and any other treatment side effects.Seventy four patients who were treated with Etonogestrel implants completed the 24-month follow-up in which we found a significant decrease in pelvic pain VAS scores comparing baseline scores to 6, 12, and 24 months (baseline: 6.39 ± 2.35 to 24-month: 0.17 ± 0.69, P < 0.05). The menstrual volume decreased significantly compared with that at baseline ((40.69 ± 30.92) %, P < 0.05). However, vaginal bleeding, amenorrhea, weight gain, and acne occurred after treatment in some patients.Etonogestrel implants were effective in reducing pelvic pain and menstrual flow of adenomyosis or endometriosis.

Twelve-month Continuation of the Etonogestrel Implant in Adolescents With Polycystic Ovary Syndrome

STUDY OBJECTIVE

To identify why adolescents with polycystic ovary syndrome (PCOS) chose the etonogestrel (ENG) contraceptive implant, to determine the 12-month continuation rate, and to characterize factors related to discontinuation.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective chart review of adolescents seen at a tertiary care children's hospital between July 1, 2008, and August 30, 2019, with PCOS diagnosis confirmed per National Institutes of Health criteria and ≥12-month ENG follow-up.

INTERVENTIONS AND MAIN OUTCOME MEASURES

Demographic characteristics, reasons for ENG insertion and removal, and information on other hormonal/contraceptive therapies were collected. Patients were categorized as ENG continuers (use ≥12 months) or discontinuers (removal at <12 months), and groups were compared.

RESULTS

A total of 96 patients met inclusion criteria (age 17.7 ± 2.2 years, body mass index 34.8 ± 8 kg/m²). Reasons for ENG were documented in 74% (51% contraception, 32% ease of use, 15% other, 13% estrogen avoidance). In all, 27% had never been sexually active, and 67% had had prior sexual activity. Treatments prior to ENG placement included 74% combined hormonal contraception, 20% medroxyprogesterone acetate withdrawal, and 17% depot medroxyprogesterone. A total of 77% continued ENG at 12 months. The main reasons for discontinuation were bleeding (41%), concern about weight gain (23%), and mood changes (18%). No preimplantation characteristics were independently predictive of continuation, although 100% of patients with type 2 diabetes (n = 11) continued. Patients who sought additional care, including telephone calls (41% vs 12%, P = .006) and clinic visits (64% vs 20%, P < .001) were more likely to discontinue.

CONCLUSIONS

The ENG implant was well tolerated in adolescents with PCOS and similar to published 12-month continuation rates.

Effects of progestin-only contraceptives on the endometrium

INTRODUCTION

The contraceptive activity of synthetic progestins is mediated through three basic mechanisms: (a) An anti-gonadotrophic action leading to the inhibition of ovulation; (b) Changes in cervical mucus characteristics that inhibit sperm penetration and (c) desynchronization of the endometrial picture necessary for implantation.

AREAS COVERED

Mechanisms involved in the progestin-induced endometrium desynchronization are individually reviewed for each of the routes of administration and, whenever possible, by individual members of the various families of synthetic progestin derivatives.

EXPERT OPINION

For contraceptive purposes, progestins are today administered through several routes: orally, as injections, subdermally and via the vagina or the uterine cavity. Given this variety of modalities, their effects may differ, depending on the route of administration, concentration reached at the level of the endometrium and the duration of use. These are characterized by inactivation of the endometrium. Progestin-only contraception provides a safe and effective control of fertility regulation, although, they are associated with the problem of endometrial break through bleeding that may lead to discontinuation. Unfortunately, in spite of a major research effort over two decades, there is not, as yet, an established long-term intervention available to manage bleeding irregularities, making mandatory a deeper understanding of the mechanisms involved is required.

Etonogestrel Subdermal Implant-Associated Regression of Endometrial Intraepithelial Neoplasia

BACKGROUND

Endometrial intraepithelial neoplasia is a precursor lesion to endometrial adenocarcinoma. Total hysterectomy is the preferred management, but systemic or locally acting progestin therapies are acceptable alternatives. The use of the etonogestrel subdermal implant for treatment of endometrial intraepithelial neoplasia has not been studied.

CASE

A 36-year-old woman, G2P2002, with obesity presented with abnormal uterine bleeding. Her endometrial specimen demonstrated endometrial intraepithelial neoplasia. She declined both hysterectomy and conventional medical management. The etonogestrel implant was offered as an alternative to no treatment. After etonogestrel implant insertion, serial biopsies showed regression of endometrial intraepithelial neoplasia. Sixteen months after implant insertion, biopsy showed inactive and atrophic endometrium.

CONCLUSION

The etonogestrel subdermal implant should be considered for further study for the treatment of endometrial intraepithelial neoplasia in women who decline surgical management.

Treatment of Adenomyosis with Subcutaneous Etonogestrel Implants: A Clinical Observational Study in 17 Patients

Background

Adenomyosis is a cause of chronic pelvic pain in women of reproductive age. The aim of this study was to investigate the effects of subcutaneous etonogestrel implantation on adenomyosis.

Material/Methods

A clinical observational study included 17 women with adenomyosis who were treated with subcutaneous etonogestrel implants and followed-up for 12 months. Imaging and clinical observations were undertaken in the 17 patients at baseline (time 0), and at 3 months, 6 months, and 12 months following subcutaneous etonogestrel implantation. The following imaging and clinical findings were compared between baseline (time 0) and 12-month follow-up: menstrual bleeding pattern, dysmenorrhea, visual analog scale (VAS) pain score, uterine volume, serum cancer antigen 125 (CA125) levels, hemoglobin, follicle-stimulating hormone (FSH) levels, luteinizing hormone levels, serum estradiol levels, and any treatment side effects.

Results

All 17 patients treated with etonogestrel implants completed the 12-month follow-up, at which time, the mean hemoglobin level (127.08±2.56 g/L) was significantly higher compared with that at baseline (94.54±5.47 g/L; P<0.01); uterine volume, serum CA125, and VAS score for dysmenorrhea at 12 months (118.03±12.83 cm³, 34.58±9.66 U/mL, and 1.45±0.35, respectively) were significantly lower when compared with baseline (198.53±39.47 cm³, 100.41±49.89 U/mL, and 7.62±0.74, respectively) (P<0.01, for all). However, changes in bleeding pattern and amenorrhoea occurred after treatment in some women.

Conclusions

Subcutaneous etonogestrel was effective in reducing some symptoms and signs of adenomyosis, including dysmenorrhea, anemia, serum CA125, and uterine volume.

Effects of etonogestrel implant on quality of life, sexual function, and pelvic pain in women suffering from endometriosis: results from a multicenter, prospective, observational study

PURPOSE

Progestins are successfully employed as treatment for endometriosis. Our study evaluates the effects of the etonogestrel (ENG) implant on pelvic pain, quality of life, and sexual function in women requiring long-term reversible contraception and presenting ovarian cysts of probable endometriotic origin.

METHODS

We enrolled 25 women asking for contraception with the ENG implant and presenting a cyst with the ultrasound features of an endometrioma and pain symptoms. Patients were interviewed on pain symptoms (dysmenorrhea, dyspareunia, dyschezia, and dysuria) using a VAS score (0-10), on quality of life (QoL) using the Short Form-36 questionnaire, and on sexual activity using the Female Sexual Function Index (FSFI) questionnaire before inserting the implant (T0) and after 6 (T1) and 12 months (T2).

RESULTS

We found a significant decrease in dysmenorrhea and dyspareunia VAS scores comparing baseline scores to 6 and 12 months. After 12 months, the bodily pain, general health, vitality, social functioning, and mental health domains of the QoL score were significantly improved. The total FSFI score results increased in comparison with baseline both at 6 and 12 months. In particular, we highlighted a significant improvement in desire, satisfaction, and pain domains already at 6 months; the arousal domain improved only after 12 months. Finally, mean diameters of endometrioma-like cysts were not changed after 12 months of treatment.

CONCLUSIONS

Etonogestrel implants seem to be able to reduce pelvic pain, improve sexual function, and quality of life in patients with ovarian cysts suspected of endometriotic origin.

Microbial transformation of contraceptive drug etonogestrel into new metabolites with Cunninghamella blakesleeana and Cunninghamella echinulata

Biotransformation of a steroidal contraceptive drug, etonogestrel (1), (13-ethyl-17β-hydroxy-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-3-one) was investigated with Cunninghamella blakesleeana and C. echinulata. Five metabolites 2-6 were obtained on incubation of 1 with Cunninghamella blakesleeana, and three metabolites, 2, 4, and 6 were isolated from the transformation of 1 with C. echinulata. Among them, metabolites 2-4 were identified as new compounds. Their structures were deduced as 6β-hydroxy-11,22-epoxy-etonogestrel (2), 11,22-epoxy-etonogestrel (3), 10β-hydroxy-etonogestrel (4), 6β-hydroxy-etonogestrel (5), and 14α-hydroxy-etonogestrel (6). Compounds 1-6 were evaluated for various biological activities. Interestingly, compound 5 was found to be active against β-glucuronidase enzyme with IC₅₀ value of 13.97±0.12μM, in comparison to standard compound, d-saccharic acid 1,4-lactone (IC₅₀=45.75±2.16μM). Intestinal bacteria produce β-glucuronidase. Increased activity of β-glucuronidase is responsible for the hydrolyses of glucuronic acid conjugates of estrogen and other toxic substances in the colon, which plays a key role in the etiology of colon cancer. Inhibition of β-glucoronidase enzyme therefore has a therapeutic significance. Compounds 1-6 were also found to be non cytotoxic against 3T3 mouse fibroblast cell lines.

A prospective cohort study of early postpartum etonogestrel implant (Implanon®) use and its effect on duration of lochia

BACKGROUND

Etonogestrel (ENG) implants (Implanon(®)/Nexplanon(®)/Implanon NXT(®)) are employed as contraception in early postpartum patients. Follow-up is often not conducted by the hospital prescriber. Little is known about duration of lochia, in a modern setting, and even less is known about the effect of ENG implants on lochia.

AIMS

To determine if early postpartum (pre-discharge) insertion of Implanon for contraception was associated with a significant difference in duration of lochia. To record the number of patients who went on to have their Implanon removed during the study period and the reasons for removal.

METHODS

Prospective cohort study of 152 postpartum patients from a tertiary maternity unit in Hobart, Tasmania, Australia. The treatment group was women requesting Implanon prior to discharge. Controls were recruited from the same unit over the same time period, with the aim to match for birth weight and parity. Information was collected during face-to-face interviews or via telephone contact. Multivariate survival analysis was used to investigate lochia duration.

RESULTS

There were 73 controls and 79 women who had early postpartum Implanon inserted. Fourteen (17.7%) patients in the treatment group had their Implanon removed during the postpartum study period. In all of these cases the reason for removal was bleeding disturbance - prolonged or intermittent vaginal bleeding beyond 50 days postpartum. There was no significant difference in duration of lochia between the groups [median predicted duration 25 days (95% CI 22-27) in controls and 24 days (95% CI 21-26) in the treatment group].

CONCLUSIONS

Early postpartum insertion of Implanon for contraception was not associated with a statistically or clinically significant difference in duration of lochia.

Investigating Potential Effects of the Contraceptive Implanon on the Behavior of Free-Ranging Adult Female Barbary Macaques

In recent years, the use of hormonal contraception in captive, free-ranging, and wild mammal populations has increased, but the effects on these nonhuman animals' behavior and the associated welfare impacts remain poorly understood. This study of free-ranging adult female Barbary macaques (Macaca sylvanus) at Trentham Monkey Forest compared females implanted with the progestin-only contraceptive Implanon to those not receiving contraception. Females with contraceptive implants had higher rates of self-scratching and spent more time self-grooming (2 behavioral indexes of anxiety) than those without implants. They also directed more aggression at others, spent more time receiving grooming and traveling, and spent less time giving grooming and resting. No significant differences between the 2 groups of females were seen for time spent foraging. These results suggest that Implanon had a number of effects on Barbary macaques, although these need to be considered in light of the significant benefits afforded by the use of this contraceptive. The findings of this study provide important information to those evaluating the relative welfare costs and benefits of alternative methods of population control in this and other species.

Bleeding profile in users of an etonogestrel sub-dermal implant: effects of anthropometric variables. An observational uncontrolled preliminary study in Italian population

PURPOSE

The purpose of this study is to evaluate the menstrual profile in users of the etonogestrel (ENG)-releasing implant (Nexplanon®) and the possible correlation with anthropometric variables.

METHODS

Ninety-two healthy women, desiring long-term contraception with the ENG implant were enrolled in a prospective observational study. Anthropometric variables were measured at baseline and after 3, 6, 9, and 12 months. Patients recorded daily the occurrence of any bleeding or spotting. The bleeding/spotting pattern was evaluated over consecutive 90-day intervals ("Reference Periods" - RPs). Patients who showed a favourable bleeding profile (amenorrhoea, infrequent, or normal bleeding) for 50% or more of the RPs were assigned to group A, while patients with a favourable bleeding profile for less than 50% of the RPs were assigned to group B.

RESULTS

Sixty-eight women (79%) were assigned to group A; 18 (21%) to group B. Group B had a lower baseline body mass index (BMI) than group A (24.84 ± 4.95 kg/m(2) versus 20.75 ± 4.41 kg/m(2); p < 0.005).

CONCLUSIONS

The ENG sub-dermal implant is a well-tolerated contraceptive method, with a high proportion of women experiencing a favourable bleeding profile. The lower basal BMI in Group B in comparison with Group A may account for the higher percentage of irregular bleeding.

Nexplanon: the new implant for long-term contraception. A comprehensive descriptive review

Nexplanon(®) is a new long-term reversible contraception method. The current review is aimed to analyze the published data concerning the contraceptive effectiveness of Nexplanon(®) and its effects on reproductive function. Pharmacological properties and technical procedures of insertion and removal, as well as the efficacy and safety data available, were discussed. Possible strategies for treating Nexplanon(®)-related bleeding were also described. With regard to the future research and the future scientific developments of contraceptive implants, the possible use of Nexplanon(®) wide-ranging for the symptomatic treatment of endometriosis and premenstrual syndrome (PMS) were considered. Finally, it was defined in which women the use of Nexplanon(®) is indicated and in which it is contra-indicated.

Effect of etonogestrel contraceptive implant (Implanon) on portal blood flow and liver functions

BACKGROUND

This study was conducted to evaluate changes in portal blood flow and liver functions among women using Implanon for 2 years.

STUDY DESIGN

Fifty healthy Implanon users were enrolled in this longitudinal study and followed up for 24 months. Portal blood flow, assessed by color Doppler; prothrombin time and concentration; serum albumin; bilirubin; gamma-glutamyl transferase (GGT); alanine aminotransferase (ALT); and aspartate aminotransferase (AST) were measured before and 24 months after insertion.

RESULTS

After 24 months of Implanon insertion, there were no significant changes in portal blood flow, serum albumin, prothrombin time or concentration. However, there was a significant increase in serum levels of total and unconjugated bilirubin and GGT and a significant decrease in ALT and AST levels. All levels, however, remained within the normal range of values.

CONCLUSIONS

Implanon use for 2 years does not seem to influence portal hemodynamics. Changes in serum levels of bilirubin, GGT, ALT and AST are unlikely to be of clinical significance.

A pilot study to assess the effect of three short-term treatments on frequent and/or prolonged bleeding compared to placebo in women using Implanon

BACKGROUND

The major side-effect of progestogen-only contraception is disruption of menstrual bleeding patterns, which can lead to a high incidence of early discontinuation. The aim of this study was to compare three treatments with placebo on the duration and recurrence of frequent and/or prolonged bleeding in Implanon users.

METHOD

Women between the ages of 18 and 45 years, who had used Implanon for > or =3 months and were experiencing prolonged or frequent bleeding patterns, were recruited at four Australian sites. Subjects were randomized to treatment using computer-generated random number table if they met the World Health Organization criteria for prolonged and/or frequent bleeding in the previous 90 days [Belsey, E.M., Pinol, A.P.Y. and Taskforce on Long-Acting Systemic Agents for Fertility Regulation, World Health Organization (1997) Contraception 55,57-65]. Treatments were: (1) mifepristone 25 mg given twice on day 1 followed by 4 days of twice daily placebo; (2) mifepristone 25 mg given twice on day 1 followed by 4 days of ethinyl estradiol (EE) 20 microg in the morning and placebo at night; (3) doxycycline 100 mg twice daily for 5 days; and (4) placebo twice daily for 5 days. Analysis was by intention to treat. The primary endpoint was the number of days of bleeding and spotting immediately following initiation of the 5 day course of each active therapy compared with placebo.

RESULTS

A total of 179 women was assigned to treatment. Both mifepristone in combination with EE and doxycycline alone were significantly more effective in stopping an episode of bleeding {mean 4. 3 days [confidence interval (CI) 3.5-5.2], and 4.8 days (CI 3.9-5.8) respectively} than mifepristone alone or placebo [5.9 days (CI 4.8-7.2) and 7.5 days (CI 6.1-9.1) respectively]. No effect on subsequent bleeding patterns was observed in any treatment group.

CONCLUSION

Both mifepristone plus EE and doxycycline alone were significantly more effective than placebo in terminating an episode of bleeding in women with prolonged and/or frequent bleeding using Implanon. We believe that the observed reduction in the number of bleeding days by almost 50% compared to placebo in both the mifepristone combination group and the doxycycline group demonstrates a clinically significant improvement in bleeding patterns and that further trials are needed to compare different combinations of therapy as well as multiple dosing regimens in order to establish which is the most effective treatment option. The effect of repeat administration or combinations of these preparations on long-term bleeding patterns requires further investigation.

[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.

Risk-benefit effects of implantable contraceptives in women

Contraceptive implant technology has been used by millions of women throughout the world. The three marketed implant systems today are levonorgestrel-releasing implants: Norplant and Jadelle, and a single etonogestrel-releasing implant, Implanon. The main benefits common to these delivery systems are their safety, high effectiveness, ease of use, long duration of action (3 - 5 years) and reversibility. Bleeding disturbances are the main adverse events associated with implantable contraceptives. Other minor risks relate to the insertion and removal procedures, which require adequately trained providers as well as aseptic techniques. Furthermore, since initiation and discontinuation of use is provider-dependent and not controlled by the user, there may be a risk of coercion of use on the one hand or, on the other hand, difficulty in access to initiating use, if trained providers are not readily available. Although no single contraceptive method is perfect or appealing to all, contraceptive implants are safe and fulfil a very important need among fertility regulation methods.

Ultrasonographic features of the endometrium and the ovaries in women on etonogestrel implant

OBJECTIVE

To evaluate the ultrasound features of the endometrium and ovaries in women on etonogestrel implant, and to correlate these features with the bleeding pattern.

METHODS

Observational study including 188 consecutive women presenting for follow-up transvaginal ultrasound examination after insertion of an etonogestrel implant contraceptive device. Thirty women had more than one follow-up examination. The bleeding pattern was considered abnormal if, in the last 3 months, there were more than five episodes of vaginal bleeding, or there was prolonged bleeding exceeding 14 consecutive days.

RESULTS

At first follow-up examination, the mean age was 29.7 years and 47% of women had an abnormal bleeding pattern. Most bleeding episodes were of less intensity than menses. The mean endometrial thickness (ET) on ultrasound was 2.9 mm (standard deviation, 2.0). Ovarian follicle growth exceeding 5 mm was observed in 60% of the cases. Ovulation was demonstrated in one woman. Univariate analysis showed a positive association (P < 0.01) between ET, bleeding pattern, and bleeding intensity. Follicle growth was positively associated (P < 0.01) with ET, bleeding pattern, and interval between insertion and examination. Multivariate analysis showed that the ET was on average 1.25 mm greater in women with abnormal bleeding (P = 0.0001). The odds of finding follicle growth were 2.8 times higher (95% confidence interval, 1.2-6.2) in women presenting with a three-layer type of endometrial morphology. There was no association between the other patients' characteristics and the bleeding pattern.

CONCLUSIONS

Abnormal uterine bleeding in women on etonogestrel implant was associated with follicle growth and a thicker, three-layer type of endometrium, suggesting incomplete ovarian inhibition and estrogen stimulation of the endometrium.