The pharmacodynamics and efficacy of Implanon. An overview of the data

Effects of an estrogen-free, desogestrel-containing oral contraceptive in women with migraine with aura: a prospective diary-based pilot study

BACKGROUND

Migraine with aura (MA) is a contraindication to the use of combined oral contraceptives (COCs) because of the increased risk of ischemic stroke. Progestogen-only contraceptive pill (POP) is a safe alternative to COCs and it is preferable in women with cerebrovascular diseases or risk factors for stroke.

STUDY DESIGN

Prospective diary-based pilot study. Thirty women with MA (n = 15 who have never used COCs and n = 15 who had previously used COCs were diagnosed according to the International Headache Society criteria. The observational period lasted 9 months during which women filled in a diary with the clinical characteristics of headache attacks. After a 3-month run-in period, each subject received an estrogen-free desogestrel (DSG) (75 mcg/day)-containing OC (Cerazette(®); Schering-Plough, formerly NV Organon, Oss, The Netherlands). Follow-up evaluations were planned at the end of the third and sixth month of treatment.

RESULTS

The number (mean±S.D.) of migraine attacks was significantly reduced both in previous COCs users (from 3.9±1.0 to 2.9±0.8; p<.001) and nonusers (from 3.2±0.9 to 2.6±1.3; p<.02) following 6 months of POP use in comparison with the run-in period. Duration of headache pain did not differ significantly in both groups throughout the study. Interestingly enough, a beneficial POP effect on the duration (mean±S.D.) of visual aura (from 16.3±9.5 to 11.4±5.6 min) and on the total duration (mean±S.D.) of neurological symptoms (from 33.6±23.3 to 18.6±18.0 min) was only significantly reported by previous COCs users (p<.001, for both) by the end of the study period. The POP was well tolerated by each woman and the bleeding pattern was variable with a tendency towards infrequent bleeding.

CONCLUSIONS

The present study supports the use of the POP containing desogestrel in a population of women with MA and underlines a positive effect on symptoms of aura, especially in MA sensitive to previous use of COCs.

Examining the efficacy, safety, and patient acceptability of the etonogestrel implantable contraceptive

Contraceptive implants provide long-acting, highly effective reversible contraception. The etonogestrel implant (ENG implant) is a single rod implant that offers three years of efficacy. The ENG implant was designed to provide contraceptive efficacy by inhibiting ovulation and Pearl Index scores reported for this method are similar to other long-acting reversible contraception as well as similar to sterilization. The implant has been shown to be safe during breast feeding and may improve symptoms of dysmenorrhea and endometriosis. Irregular bleeding patterns can be expected with the device's use and should be addressed in order to decrease rates of discontinuation.

Cost effectiveness of contraceptives in the United States

BACKGROUND

The study was conducted to estimate the relative cost effectiveness of contraceptives in the United States from a payer's perspective.

METHODS

A Markov model was constructed to simulate costs for 16 contraceptive methods and no method over a 5-year period. Failure rates, adverse event rates and resource utilization were derived from the literature. Sensitivity analyses were performed on costs and failure rates.

RESULTS

Any contraceptive method is superior to "no method". The three least expensive methods were the copper-T intrauterine device (IUD) (US$647), vasectomy (US$713) and levonorgestrel (LNG)-20 intrauterine system (IUS) (US$930). Results were sensitive to the cost of contraceptive methods, the cost of an unintended pregnancy and plan disenrollment rates.

CONCLUSION

The copper-T IUD, vasectomy and the LNG-20 IUS are the most cost-effective contraceptive methods available in the United States. Differences in method costs, the cost of an unintended pregnancy and time horizon are influential factors that determine the overall value of a contraceptive method.

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.

Implanon: a new contraceptive implant

Women who cannot use hormonal contraception containing estrogen have a variety of progestin-only contraceptive methods from which to choose. Implanon is a new single-rod progestin-only contraceptive implant that is easily inserted and can remain in place for up to 3 years. It is highly effective with a rapid onset of action and an equally rapid return of fertility once removed. Counseling is important to help women decide if this method is appropriate for their needs.

Side effects and acceptability of Implanon: a pilot study conducted in eastern Turkey

OBJECTIVE

To assess side effects during the first 6 months of use of Implanon.

DESIGN AND METHODS

The study was conducted in eastern Turkey between June 2004 and May 2005. Forty-one healthy women, aged 18-40 years who chose to use Implanon participated in the study. The implant was inserted between days 1 and 5 of the menstrual cycle. Findings were recorded before and during 6 months following insertion. Statistical analyses were performed using SPSS package programme including paired samples t-test.

RESULTS

No pregnancy occurred during the study. Ninety days after initiation of therapy, three of the 41 patients (7.3%) had regular periods, 14 (34.1%) were amenorrhoeic and the remaining 24 (58.5%) had some type of abnormal bleeding. Dysmenorrhoea affected significantly less women (1/41, i.e. 2.4%) than before treatment (17/41, i.e. 41.5%), but mastalgia increased significantly as it was reported by five previously unaffected participants (12.2%). Mood changes appeared in seven patients (17.1%) and acne in 11 of them (26.8%). The circulating levels of protein C, total cholesterol and oestradiol dropped significantly. Endometrial thickness decreased significantly. At completion of the study period, removal of the implant was requested by eight of the 41 patients (19.5%) because of irregular bleeding (six women), depressive symptoms requiring treatment (one woman) or weight gain (one woman).

CONCLUSIONS

Mainly because of irregular bleeding, the discontinuation rate of Implanon at 6 months among the women in this region is high (19.5%).

A three-year longitudinal evaluation of the forearm bone density of users of etonogestrel- and levonorgestrel-releasing contraceptive implants

Background

The aim of this study was to evaluate bone mineral density (BMD) at baseline and at 18 and 36 months of use of etonogestrel (ENG)-and levonorgestrel (LNG)-releasing contraceptive implants. This is a continuation of a previous study in which BMD was evaluated at baseline and at 18 months of use.

Methods

A total of 111 women, 19–43 years of age, wererandomly allocated to use one of the two implants. At 36 months of follow-up, only 36 and 39 women were still using the ENG- and LNG-releasing implants, respectively. BMD was evaluated at the distal and at the ultra-distal radius of the non-dominant forearm using dual-energy X-ray absorptiometry.

Results

There was no difference in the BMD of users of either implant at 18 and at 36 months. BMD was significantly lower at 18 and at 36 months at the distal radius in both groups of users compared to pre-insertion values; however, no difference was found at the ultra-distal radius.

Conclusion

Women 19–43 years of age using either one of these two contraceptive implants for 36 months had lower BMD values at the distal radius compared to pre-insertion values; however, no difference was found at the ultra-distal radius.

Subdermal implantable contraceptives versus other forms of reversible contraceptives or other implants as effective methods of preventing pregnancy

BACKGROUND

Implantable methods of contraception offer long-acting reversible contraception. Their uptake rate in comparison to other contraceptive methods, particularly in developed countries, has historically been low.

OBJECTIVES

To assess the contraceptive effectiveness, tolerability and acceptability of subdermal implants in comparison to other reversible contraceptive methods.

SEARCH STRATEGY

Literature were identified through database searches, reference lists and individuals/organisations working in the contraceptive field.

SELECTION CRITERIA

All randomised and controlled trials comparing subdermal implants with other forms of reversible contraceptives and reporting on pre-determined outcomes in women of reproductive years. Primary outcomes were pregnancy and continuation.

DATA COLLECTION AND ANALYSIS

Quality assessment of studies and data extraction were completed independently by two reviewers. A quality checklist was designed to identify general methodological and contraceptive specific factors. Study authors and pharmaceutical companies were contacted to provide additional data.Data were collected on pregnancy rates, continuation, side effects and adverse events.

MAIN RESULTS

All nine identified trials compared different types of contraceptive implant. Eight, involving 1578 women, compared Implanon with Norplant , and one, involving 1198 women, compared Jadelle with Norplant. There was no difference between Implanon and Norplant for contraceptive effectiveness rates or continuation over 4 years. Both were highly effective methods of contraception with no pregnancies occurring in any of the trials during 26,972 and 28,108 women months of follow up respectively. The most common side-effect with Implanon and Norplant was changes in bleeding pattern. The pattern with Implanon was initially more variable, bleeding with both implants became less frequent with duration of use. After two years use the amenorrhoea rate was significantly higher with Implanon. The trials reported no significant difference in hormonal side-effects or adverse events. Implanon was significantly quicker to insert and remove than Norplant. There was no difference in contraceptive effectiveness and in continuation rates between Jadelle and Norplant. Jadelle was significantly quicker to remove than Norplant.

AUTHORS' CONCLUSIONS

Implanon, Norplant and Jadelle are highly effective contraceptive methods. No significant differences were found in contraceptive effectiveness or continuation. The most common side-effect with all implants was unpredictable vaginal bleeding. Time taken for removal of Implanon and Jadelle was less than that for Norplant.Although this systematic review was unable to provide a definitive answer on relative effectiveness, tolerability and acceptability of contraceptive implants in comparison to other contraceptive methods, it has raised issues around the conduct of contraceptive research.

Removal of etonogestrel contraceptive implants in the operating theater: report on 28 cases

OBJECTIVES

We describe removal procedures for etonogestrel contraceptive implants in the operating theater. In addition, we discuss the management of removal of contraceptive implants that are difficult to palpate or are impalpable.

DESIGN

We conducted a retrospective single-center case series analysis of Implanon removals conducted at a university hospital between January 2002 and April 2005.

MATERIALS AND METHODS

We analyzed case notes for 28 patients who had their contraceptive implant removed in the operating theater.

RESULTS

Intermenstrual bleeding was the principal reason for removal (52.4%). Ten patients already had one attempted removal of their implant. Preoperative ultrasound localized the implant in all cases. Half of the removals were done under local anesthetic, with three cases progressing to general anesthesia (11%). Thirty percent of the implants had migrated from their initial implantation, 37% were in intramuscular tissue and 11% were in the humeral neurovascular sheath. The only postoperative complications were one small seroma and transient paresthesia in the territory of the ulnar nerve. The implant was not found in one case.

CONCLUSIONS

The removal of an implant that is not palpable or difficult to palpate should take place in the operating theater following localization by ultrasound. Patients must be fully informed about the procedure, including its complications and the risk for failure.

Contraception today

Modern contraceptive methods represent more than a technical advance: they are the instrument of a true social revolution-the "first reproductive revolution" in the history of humanity, an achievement of the second part of the 20th century, when modern, effective methods became available. Today a great diversity of techniques have been made available and-thanks to them, fertility rates have decreased from 5.1 in 1950 to 3.7 in 1990. As a consequence, the growth of human population that had more than tripled, from 1.8 to more than 6 billion in just one century, is today being brought under control. At the turn of the millennium, all over the world, more than 600 million married women are using contraception, with nearly 500 million in developing countries. Among married women, contraceptive use rose in all but two developing countries surveyed more than once since 1990. Among unmarried, sexually active women, it grew in 21 of 25 countries recently surveyed. Hormonal contraception, the best known method, first made available as a daily pill, can today be administered through seven different routes: intramuscularly, intranasally, intrauterus, intravaginally, orally, subcutaneously, and transdermally. In the field of oral contraception, new strategies include further dose reduction, the synthesis of new active molecules, and new administration schedules. A new minipill (progestin-only preparation) containing desogestrel has been recently marketed in a number of countries and is capable of consistently inhibiting ovulation in most women. New contraceptive rings to be inserted in the vagina offer a novel approach by providing a sustained release of steroids and low failure rates. The transdermal route for delivering contraceptive steroids is now established via a contraceptive patch, a spray, or a gel. The intramuscular route has also seen new products with the marketing of improved monthly injectable preparations containing an estrogen and a progestin. After the first device capable of delivering progesterone directly into the uterus was withdrawn, a new system releasing locally 20 microg evonorgestrel is today marketed in a majority of countries with excellent contraceptive and therapeutic performance. Finally, several subcutaneously implanted systems have been developed: contraceptive "rods," where the polymeric matrix is mixed with the steroid and "capsules" made of a hollow polymer tube filled with free steroid crystals. New advances have also been made in nonhormonal intrauterine contraception with the development of "frameless" devices. The HIV/AIDS pandemic forced policy makers to look for ways to protect young people from sexually transmitted diseases as well as from untimely pregnancies. This led to the development of the so-called dual protection method, involving the use of a physical barrier (condom) as well as that of a second, highly effective contraceptive method. More complex is the situation with antifertility vaccines, still at a preliminary stage of development and unlikely to be in widespread use for years to come. Last, but not least, work is in progress to provide effective emergency contraception after an unprotected intercourse. Very promising in this area is the use of selective progesterone receptor modulators (antiprogestins).

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.

Migration of Implanon

OBJECTIVE

To determine whether or not migration of the Implanon rod does occur if correctly positioned and, if indeed migration does occur, to measure the degree of such migration.

METHODS

A prospective study of 100 women who requested and had Implanon rods inserted by one fully trained health care professional holding the Faculty of Family Planning and Reproductive Health Care Letter of Competence in Subdermal Contraceptive Implant Techniques. Measurements were made from the insertion site to the distal end of the rods at 3 and 12 months post-insertion.

RESULTS

Of the 100 women studied, 95 were seen for follow-up at 3 months. There was no migration of Implanon in 58 (61%) patients. Of the remaining 37 (39%) patients where migration had occurred, 34 showed migration caudally and only three demonstrated cranial migration. With regard to the degree of migration, all but one case showed this to be less than 2 cm either cranially or caudally. At 1-year follow-up 87 patients were seen. No migration was noted in 39 (45%) patients. In the remaining 48 (55%) patients where migration had occurred, 44 showed migration caudally and only four demonstrated cranial migration, which in one case was over 2 cm. With regard to the degree of migration, all but one case showed this to be less than 2 cm either cranially or caudally. The measurement in the single case showing migration over 2 cm at 3 months remained the same at the 1-year follow-up.

CONCLUSIONS

These results show that up to 1 year after insertion of Implanon significant migration of the rod does not occur. The degree of migration noted in all cases except one was less than 2 cm. Where migration was noted, in the majority of cases this occurred caudally towards the insertion site. There were no cases of deep migration.

Ovarian cysts in users of Implanon® and Jadelle® subdermal contraceptive implants

OBJECTIVE

To evaluate the prevalence of ovarian cysts in users of two contraceptive implants compared to users of intrauterine contraceptive (IUC).

MATERIALS AND METHODS

A total of 344 women were enrolled at 3 months of use of the etonogestrel-releasing implant (Implanon), the levonorgestrel-releasing implant (Jadelle) or the TCu380A IUC. Bimanual pelvic examination and vaginal ultrasound were performed during routine 3-, 6- and 12-month visits of asymptomatic women. Women with ovarian cysts (or enlarged ovarian follicles > or = 25 mm) were assessed weekly until disappearance or reduction of the image [including estradiol (E2) and progesterone (P) measurement], and women with no ovarian enlargement underwent the same evaluation for the same period of time.

RESULTS

Ovarian cysts were detected in 5.2%, 13.0% and 1.9% of users of Implanon, Jadelle and IUC, respectively, at 3 months. At 6 months of use, prevalence was 7.2%, 8.0% and 2.1%, whereas 12-month rates were 26.7%, 14.6% and 1.2% in the three groups, respectively. E2 levels were significantly higher among users with ovarian cysts than controls. The time until disappearance of the ovarian cyst was similar in all three groups. There were more cases of menorrhagia in users of implants who had ovarian cysts than in those with no ovarian enlargement.

CONCLUSIONS

The finding of ovarian cysts or enlarged ovarian follicles during the first year of use of Implanon and Jadelle implants is common and transient and should not be interpreted as a pathologic ovarian cyst. No further medical interventions are necessary.

Non-oral reversible contraceptive methods

There are many contraceptives in the world market today. Knowledge of the vast spectrum of contraceptive methods is essential to the everyday practice of healthcare personnel. Such knowledge translates to improved care and access for women so they can obtain and utilize the appropriate contraception for their individual needs. This is a review of non-oral and nonsurgical contraceptive methods.

[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.

Contraception: an international perspective

Although it is estimated that the population growth rate will decline to a replacement level by 2050, it is also now predicted that the total world population will reach 8.9 billion in that year -- far higher than the 2004 estimate of 6.4 billion. More than 26 billion new couples will need contraceptives in the next half century. Although a steady increase in contraceptive use has been observed in both developed and developing countries, the contraceptive needs of a high percentage of couples have not yet been met and the number of unplanned pregnancies continues to increase. The actual use of contraception differs from region to region. Although no new method has been registered for many years, several new products have been marketed during the last 5. Among these are new implants, medicated intrauterine systems, contraceptive vaginal rings, transdermal patches and several new combined oral contraceptive formulations. New contraceptive methods have been developed to meet the objectives of expanding contraceptive choices for both women and men and answering an unmet need for contraceptives with a long-term action that meet the expectations of consumers. Simplicity, reversibility and effectiveness are the desired features of a male contraceptive, but no new male contraceptive method is yet available. New areas of basic research include studies on genes, proteins and enzymes involved in the reproductive system. The new methods will be targeted to specific interactions within the reproductive system at the level of ovaries and testes, as well as between spermatozoa and ova. This futuristic approach still keeps in mind the need for better access to existing contraceptive methods, as well as the discovery of new contraceptives that are simple to use, safe, reversible and inexpensive. In the future, contraceptives may be combined with other medicinal agents to provide dual protection against both pregnancy and other preventable conditions, such as sexually transmitted infections.

[Update on contraception]

Since the introduction of hormonal contraceptives in the 1960s, great advances have been achieved in contraception. Biological effects of sexual steroids as well as risks and benefits of oral contraception are better estimated. After the development of a new hormone-containing intra-uterine system, new hormone delivery systems offer women safe and effective contraceptive options. These new options that combine high efficacy and ease of use should allow better acceptance and compliance than daily pill ingestion and should then reduce the high rate of unintended pregnancies terminated by elective abortion. Transdermal contraceptive system and vaginal ring offer a promising innovative approach in pregnancy prevention. Subdermal implants give women the choice of a highly effective contraceptive system in spite of significant side effects. New hormonal delivery systems such as injectables are under development. Hysteroscopic tubal sterilization is now also available and is a very effective procedure. This wide variety of new contraceptive methods offers a marked improvement from previous medications for users by providing better efficacy and tolerability.

Delivery options for contraceptives

Although a steady increase in contraceptive use has been observed in developed and less-developed countries, the contraceptive needs of a significant proportion of couples have not yet been met, resulting in an increase in unplanned pregnancies. Several new contraceptive products have reached the market during the past few years. Among these are new implants, a medicated intrauterine device, contraceptive vaginal rings, transdermal patches and several new regimen of combined oral contraceptives. These new or improved methods have been developed to expand the contraceptive choices available to women and men as well as to respond to the unmet need for contraceptives with long-term activity. New targets are being identified both in the ovary and the testes for a more specific non-hormonal contraception. This futuristic approach still keeps in mind the need for better access to existing contraceptive methods, as well as the discovery of new contraceptives that are simple to use, safe, reversible and inexpensive. In recent years, there has been great interest in agents that provide dual protection against pregnancy and sexually transmitted infections (STI), especially human immunodeficiency virus (HIV). A contraceptive method providing dual medical benefits might increase motivation for consistent use, thus reducing contraceptive failures and unwanted pregnancies.

Gynecological health of females with congenital heart disease

Because of major advances in diagnostic and surgical methods, females with congenital heart disease (CHD) now survive into and beyond their reproductive years. Management of pregnancy in this patient population is well described, but gynecologic management such as menstruation, contraception and menopause have received scanty attention. Accordingly, the gynecologic health issues confronting these patients are described. Menstrual patterns in acyanotic females with CHD are similar to the general population, but cyanotic females have menstrual irregularities including amenorrhea, which implies anovulation and an increased risk of uterine carcinoma. Anticoagulants predispose to heavy vaginal bleeding and corpus luteum rupture. Contraceptives must be selected according to individual patient profiles. Hormone replacement therapy is warranted for relief of menopausal symptoms as in the general population and should be relatively safe because estrogen dose is low.

Safety and efficacy of Implanon™, a single-rod implantable contraceptive containing etonogestrel

OBJECTIVES

The safety and efficacy of a single-rod implantable contraceptive containing etonogestrel (Implanontrade mark) were investigated in a multicenter clinical trial.

STUDY DESIGN

Sexually active American women (N=330) with apparently normal menstrual cycles used the implant for up to 2 years. All subjects recorded bleeding and/or spotting daily in a diary. Safety was assessed through adverse experiences (AEs), laboratory tests and physical and gynecologic examinations.

RESULTS

Total exposure was 474 woman-years (6186 cycles), and 68% of subjects had at least 1 year of exposure. No pregnancies occurred. The most common bleeding pattern observed throughout the study was infrequent bleeding, defined as less than three episodes of bleeding in a reference period (excluding amenorrhea). The least common pattern was frequent bleeding, defined as more than five episodes of bleeding in a reference period. Infrequent, prolonged and frequent bleeding patterns were most common early in the study and declined thereafter. During the 3-month Reference Periods 2-8 (Months 4-24), the incidence of amenorrhea ranged from 14% to 20%. Forty-three subjects (13%) withdrew from the study because of bleeding pattern changes and 76 subjects (23%) discontinued because of other AEs. Other common AEs leading to discontinuation, besides bleeding irregularities, were emotional lability (6.1%), weight increase (3.3%), depression (2.4%) and acne (1.5%). Use of Implanon (etonogestrel subdermal implant, referred to herein as ENG implant) for up to 2 years had no clinically significant effects on laboratory parameters, physical and pelvic examinations, vital signs or body mass index. The average length of time required for ENG implant insertion and that for removal were 0.5 and 3.5 min, respectively, and all the procedures were uncomplicated. The return to normal menstrual cycles and fertility was rapid after removal.

CONCLUSIONS

Implanon is a safe, highly effective and rapidly reversible new method of contraception.

Pharmacological female contraception: an overview of past and future use

Female hormonal contraceptive methods have undergone slow change over the past four decades. Due to social, political and legal reasons, as well as medical complications, several new methods have been removed from the contraceptive armamentarium almost as quickly as they have been added. With worldwide unintended pregnancy rates approaching 50% of all pregnancies, there is an increased need for the development of new methods of effective, safe, acceptable hormonal contraception. Pharmacological methods of contraception are reversible and contraceptive steroids are now formulated in pills, patches, intravaginal rings, subdermal implants and injections. All currently marketed formulations are made from synthetic steroids and contain no natural oestrogens or progestins. This article reviews the current state of female contraception and explores future directions.

Unintended pregnancies with the etonogestrel implant (Implanon): a case series from postmarketing experience in Australia

This paper describes a case series of over 200 unintended pregnancies associated with the etonogestrel implant, Implanon. These cases have been reported to the Australian Adverse Drug Reactions Advisory Committee during the first 3 years of marketing in this country. Of 218 cases included, 45 had insufficient data to assess the reason for contraceptive failure and 46 women were determined to have been already pregnant prior to Implanon insertion. Of the remaining 127 cases, the most common reason for unintended pregnancy was failure to insert the implant in 84 women. Other reasons included incorrect timing of insertion (19 cases), expulsion of Implanon (3 cases) and interaction with hepatic enzyme-inducing medicines (8 cases). The remaining 13 cases were classified as product/method failures once other reasons had been excluded. Using the 204,486 Implanon devices subsidized in this period to estimate the population exposed and the 218 pregnancies reported, the approximate failure rate in postmarketing use was 1 in 1000 insertions. These findings (and reports to medical indemnity insurers) have resulted in the development of guidelines and training for doctors inserting Implanon in Australia.

Contraception for the adolescent and young adult with congenital heart disease

Increasing numbers of females born with congenital heart disease are reaching childbearing age. Practitioners involved in the management of the adolescents or adults must be aware not only of the risks of pregnancy associated with varying types of CHD but with other issues involving the reproductive cycle to provide appropriate care, counseling, and education.

Acceptabilité de l’implant contraceptif à l’étonogestrel (Implanon®)

OBJECTIVES

To estimate the exact satisfaction of women toward Implanon, the sole contraceptive implant available in France. To clarify the indications of this type of contraception.

MATERIAL AND METHOD

Among a population of 182 women with Implanon" inserted in a same family planning service between May 22, 2001 and February 14, 2003, 108 women agreed to answer a questionnaire of satisfaction. Implants were inserted in one third of cases after childbirth, in another third after abortion. The average duration of use of the implant was of 16 months (2 in 24 months). Twenty-nine removals among the 108 insertions (27%) were recorded.

RESULTS

Possibility of a long-term and easy -to-use contraception was the most common reason for choosing Implanon (74% of the women). Eighty-one percent of the women were globally satisfied with Implanon but one out of two women had side-effects. Only 62% of the women were ready to use it again. Adverse events were first, menstrual disturbance in 83% of the women, mainly amenorrhea (26%) and bleeding irregularity (40%). Bleeding irregularity was one of the main motives for discontinuing the implant in 41% of cases. Except weight gain present for 37% of patients, the other side-effects, even though they were frequent, were less often the reason for removal. Headache, acne, breast pain, mood and decreased libido were the main reasons for removal.

CONCLUSION

Implanon has certainly a place among current contraceptive methods. Because of the frequency raised by adverse events and by their lower tolerance in Europe, this place has to remain limited to the incapacity of classic methods. Preinsertion counseling announcing Implanon's benefit and risk effects is necessary to minimize the early discontinuation rates.

Recent developments in hormone delivery systems

Women who want safe, effective contraception have many more options than they did only a few years ago. Each option must be weighed carefully according to the needs and lifestyle of each particular woman. One method that provides long-term convenience with a side-effect profile that is comparable to that of oral contraceptives is the once-a-month injectable contraceptive containing 25 mg medroxyprogesterone acetate and 5 mg estradiol cypionate. Another option is the levonorgestrel-releasing intrauterine contraceptive system that offers pregnancy prevention for 5 years. Finally, hormonal implants that release low doses of progestins have been used for more than 30 years by a total of 10 million women, and easier-to-use implants will soon be available.

New options in contraception for teenagers

PURPOSE OF REVIEW

Unintended pregnancy continues to exact a considerable economic, social and personal cost in industrialized nations despite the ready availability of safe, reliable and highly effective methods of contraception. Adolescents still demonstrate some of the highest rates of unintended pregnancy and thus may benefit from considering new contraceptive options that provide unique side effect profiles or delivery systems that could facilitate and improve compliance of contraceptive methods.

RECENT FINDINGS

The recent launch of several new combination oral contraceptive pills with novel side effect profiles has expanded the choices for teenagers who choose to use a daily oral contraceptive. Of potentially greater interest is the recent availability of several nondaily contraceptives, as compliance remains a critical issue with successful contraceptive use in adolescents.

SUMMARY

New contraceptive methods bring unique side effect profiles and delivery systems that may improve overall contraceptive compliance, especially among teenagers who are more prone to misuse from a wide array of side effect and compliance issues. Even the most accepted method, however, will not provide effective contraception if the process by which contraception is provided fails to address the unique concerns and lifestyle issues of each individual adolescent.

Relative cost effectiveness of Depo-Provera, Implanon, and Mirena in reversible long-term hormonal contraception in the UK

OBJECTIVE

To estimate the relative cost effectiveness for women aged > or =30 years, starting long-term hormonal contraception with either levonorgestrel intrauterine system (Mirena), etonogestrel subdermal implant (Implanon) or medroxyprogesterone acetate injection (Depo-Provera).

DESIGN AND SETTING

This was a modelling study, performed from the perspective of the UK NHS, of contraceptive services supplied by a general practitioner. STUDY PARTICIPANTS AND INTERVENTIONS: A dataset was created from the General Practice Research database (GPRD) comprising 16 835 women aged > or =30 years who received levonorgestrel intrauterine system (n = 6080), etonogestrel subdermal implant (n = 277) or medroxyprogesterone acetate injection (n = 10 478) for their long-term contraception between 1997 and 2002.

METHODS

Contraception-related healthcare resource utilisation values and contraception continuation rates were obtained from the GPRD. The incidence of pregnancy associated with each contraceptive was obtained from the published literature. By combining the GPRD dataset with published clinical outcomes, a decision model was constructed. This was used to estimate the expected annualised direct healthcare costs and consequences of the provision of each type of contraception per woman-year in pounds sterling (pound) at 2002/03 prices.

RESULTS

Our model suggests that starting long-term contraception with levonorgestrel intrauterine system or etonogestrel subdermal implant instead of medroxyprogesterone acetate injection is a dominant strategy from the UK NHS perspective. In contrast, starting long-term contraception with etonogestrel subdermal implant instead of levonorgestrel intrauterine system is likely to be the least cost-effective option, since it would lead to an additional cost for each additional avoided pregnancy (pound 21,000).

CONCLUSION

Long-acting reversible hormonal contraception has the benefit of being extremely effective (>99%), and not reliant on patient compliance nor dependent on correct usage. The relative cost effectiveness of using any one contraceptive should be considered in the light of the additional clinical benefits it may confer, user acceptability, QOL, past medical history and the estimated cost of an unintended pregnancy. Choice of contraception is essential to meet diverse user needs and preferences that may change with the user's stage of life. Only by offering choice will the maximum number of women be protected and therefore the greatest savings to the health service be gained.

Advances in Female Hormonal Contraception

Despite the wide variety of reversible contraceptives, unintended pregnancy rates in developed nations are still considered markedly elevated by most epidemiologists and clinicians. Indeed, the US has one of the highest unintended pregnancy rates among the industrialized nations of the world. Although many factors appear to influence this problem, what may play an important role in this apparent paradox is the process by which a woman obtains contraception. Although most nonbarrier methods have similar efficacy, the ability to use that method consistently and correctly will determine whether it provides maximal contraception. Oral contraceptives are the most popular method in the US; accordingly, the process by which US women obtain their contraception may not take into account the desire of many women to use nondaily methods. The recent introduction of nondaily methods in the US and elsewhere has provided more choice so that a successful contraceptive decision can be made in the first instance rather than after an adverse clinical outcome or unintended pregnancy with a method not as well suited to that woman's lifestyle. These new methods are not characterized by improved safety or efficacy; rather, they have novel components or delivery systems that may provide important options to women who may not be able to or willing to use existing methods of contraception. The transdermal patch, vaginal ring, and monthly injectable are combination estrogen/progestogen methods characterized by novel delivery systems and compliance regimens. The single rod implant is a facile and well accepted method that has not yet been approved for use in the US but has been an increasingly popular choice elsewhere. The levonorgestrel intrauterine system has been used in Europe for over 10 years and has recently been introduced in the US. This intrauterine contraceptive provides high efficacy and reliability, and may have considerable noncontraceptive benefit with regard to the nonsurgical treatment of uterine bleeding problems and endometrial protection for menopausal hormone therapy. The increasing popularity of these methods can be considered a testament to the desire of women to consider nondaily contraceptives as first-line, mainstream options. It is hoped that increasing use of these methods will lead to a considerable decrease in the rate of unintended pregnancy.

Male contraception

The provision of safe, effective contraception has been revolutionized in the past 40 yr following the development of synthetic steroids and the demonstration that administration of combinations of sex steroids can be used to suppress ovulation and, subsequently, other reproductive functions. This review addresses the current standing of male contraception, long the poor relation in family planning but currently enjoying a resurgence in both scientific and political interest as it is recognized that men have a larger role to play in the regulation of fertility, whether seen in geopolitical or individual terms. Condoms and vasectomy continue to be popular at particular phases of the reproductive lifespan and in certain cultures. Although not perfect contraceptives, condoms have the additional advantage of offering protection from sexually transmitted infection. The hormonal approach may have acquired the critical mass needed to make the transition from academic research to pharmaceutical development. Greatly increased understanding of male reproductive function, partly stimulated by interest in ageing and the potential benefits of androgen replacement, is opening up other avenues for investigation taking advantage of nonhormonal regulatory pathways specific to spermatogenesis and the reproductive tract.

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.

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.

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.

Mechanisms that explain the contraceptive action of progestin implants for women

Four different contraceptive implants for women, in the form of capsules or covered rods, that release either one of the synthetic progestins levonorgestrel, etonogestrel, Nestorone, or Elcometrine and nomegestrol acetate were considered. These progestins act by binding to their receptors located in diverse target cells, which are distributed along the hypothalamic-pituitary-gonadal-genital tract axis. These implants differ in the extent to which each one interferes with various steps of the reproductive process and in the intensity with which each one affects the same process along its effective life, but they have in common the ability to interfere with several key processes required for gamete encounter and fertilization. The steps they interfere with most are the ovulatory process, through partial or complete inhibition of the gonadotropin surge, and by changing the quality of cervical mucus; they restrict or suppress the access of fertile spermatozoa to the site of fertilization. Changes in endometrial development also occur, but this contribution to the contraceptive action is difficult to determine at the present time.