Ovarian endocrine function through five years of continuous treatment with NORPLANT subdermal contraceptive implants

Potential biomarkers to predict return to fertility after discontinuation of female contraceptives-looking to the future

Nowadays there are multiple types of contraceptive methods, from reversible to permanent, for those choosing to delay pregnancy. Misconceptions about contraception and infertility are a key factor for discontinuation or the uptake of family planning methods. Regaining fertility (the ability to conceive) after contraceptive discontinuation is therefore pivotal. Technical studies to date have evaluated return to fertility by assessing pregnancy as an outcome, with variable results, or return to ovulation as a surrogate measure by assessing hormone levels (such as progesterone, LH, FSH) with or without transvaginal ultrasound. In general, relying on time to pregnancy as an indicator of return to fertility following contraceptive method discontinuation can be problematic due to variable factors independent of contraceptive effects on fertility, hormone clearance, and fertility recovery. Since the ability to conceive after contraceptive method discontinuation is a critical factor influencing product uptake, it is important to have robust biomarkers that easily and accurately predict the timing of fertility return following contraception and isolate that recovery from extrinsic and circumstantial factors. The main aim of this review is to summarize the current approaches, existing knowledge, and gaps in methods of evaluating return-to-fertility as well as to provide insights into the potential of new biomarkers to more accurately predict fertility restoration after contraceptive discontinuation. Biomarker candidates proposed in this document include those associated with folliculogenesis, cumulus cell expansion, follicular rupture and ovulation, and endometrial transport and receptivity which have been selected and scored on predefined criteria meant to evaluate their probable viability for advancement. The review also describes limitations, regulatory requirements, and a potential path to clinically testing these selected biomarkers. It is important to understand fertility restoration after contraceptive method discontinuation to provide users and health providers with accurate evidence-based information. Predictive biomarkers, if easy and low-cost, have the potential to enable robust evaluation of RTF, and provide potential users the information they desire when selecting a contraceptive method. This could lead to expanded uptake and continuation of modern contraception and inform the development of new contraceptive methods to widen user's family planning choices.

Effect of double-dose levonorgestrel subdermal implant in women taking efavirenz-based antiretroviral therapy: The DoubLNG pharmacokinetic study

OBJECTIVE

We evaluated the pharmacokinetics of double-dose levonorgestrel (LNG) implants to overcome the drug-drug interaction with efavirenz-based antiretroviral therapy (ART).

STUDY DESIGN

We conducted a nonrandomized, open-label, parallel-group, longitudinal pharmacokinetic study among Ugandan women ages 18-45 years. Participants with HIV on ART containing efavirenz 600 mg received 300 mg of LNG implants (Jadelle®, Bayer, New Zealand): 300LNG+ART group. We compared our outcomes with women without HIV using standard dose, 150 mg of LNG implants: 150LNG group. The implant was placed on day zero in both groups, and we quantified plasma LNG concentrations over 48 weeks post implant insertion. LNG pharmacokinetic parameters were estimated using noncompartmental techniques. Our primary outcome was the geometric mean ratio with 90% confidence intervals of LNG area under the concentration-time curve over 24 weeks (AUC_0-24w) between groups. Demographic data were described as median (interquartile range). A secondary outcome compared between-group percent of LNG concentrations ≥300 pg/mL, a minimum threshold selected a priori based on observed pregnancies in Ugandan women on standard-dose LNG implants plus efavirenz.

RESULTS

We enrolled 27 women in the 300LNG+ART group (34 [28.0 to 40.5] years and 61.0 [49.8-66.0] kg) and 19 women in the 150LNG group (33 [30.0 to 34.5] years and 64.9 [59.0 to 74.5] kg). LNG AUC_0-24w was 34% lower for 300LNG+ART versus 150LNG (geometric mean 9998 vs. 15,231 pg*week/mL, respectively [geometric mean ratio 0.66 (90% confidence intervals, 0.54 to 0.80)]). The percentage of participants with LNG concentrations ≥300 pg/mL was not statistically different between groups at week 24 (300LNG+ART: 74.1%; 150LNG: 89.5%; p = 0.27).

CONCLUSION

Double-dose LNG implant did not completely overcome the drug-drug interaction with efavirenz.

IMPLICATION

In women using ART containing efavirenz, placing two implant systems (300 mg) did not normalize LNG pharmacokinetics compared with the standard-dose implant (150 mg), and some women had evidence of ovulatory activity. Alternative ART without drug-drug interactions, such as dolutegravir, is recommended with contraceptive implants.

Nonsurgical fertility control for managing free-roaming dog populations: a review of products and criteria for field applications

About 75% of dogs worldwide are free to roam and reproduce, thus creating locally overabundant populations. Problems caused by roaming dogs include diseases transmitted to livestock and humans, predation on livestock, attacks on humans, road traffic accidents, and nuisance behavior. Nonsurgical fertility control is increasingly advocated as more cost-effective than surgical sterilization to manage dog populations and their impact. The aims of this review were to 1) analyze trends in numbers of scientific publications on nonsurgical fertility control for dogs; 2) illustrate the spectrum of fertility inhibitors available for dogs; 3) examine how differences between confined and free-roaming dogs might affect the choice of fertility inhibitors to be used in dog population management; and 4) provide a framework of criteria to guide decisions regarding the use of nonsurgical fertility control for dog population management. The results showed that the 117 articles published between 1982 and 2011 focussed on long-term hormonal contraceptives, such as gonadotropin-releasing hormone agonists, immunocontraceptives, and male chemical sterilants. The number of articles published biennially increased from one to five papers produced in the early 1980s to 10 to 20 in the past decade. Differences between confined dogs and free-roaming dogs include reproduction and survival as well as social expectations regarding the duration of infertility, the costs of sterilization, and the responsibilities for meeting these costs. These differences are likely to dictate which fertility inhibitors will be used for confined or free-roaming dogs. The criteria regarding the use of fertility control for dog population management, presented as a decision tree, covered social acceptance, animal welfare, effectiveness, legal compliance, feasibility, and sustainability. The review concluded that the main challenges for the future are evaluating the feasibility, effectiveness, sustainability, and effects of mass nonsurgical sterilization campaigns on dog population size and impact as well as integrating nonsurgical fertility control with disease vaccination and public education programs.

Effects of progesterone, levonorgestrel and medroxyprogesterone acetate on apoptosis in human endometrial endothelial cells

BACKGROUND

We evaluated apoptosis in human endometrial endothelial cells (HEECs) incubated with progesterone, levonorgestrel (LNG) and medroxyprogesterone acetate (MPA).

STUDY DESIGN

HEECs were cultured to near confluence, and the progestogens were added.

SETTING

Academic Department of Obstetrics and Gynecology.

PATIENTS

No patients were involved.

INTERVENTIONS

Progestogens at 5-, 250- and 500-ng/mL concentrations were added to incubations of HEECs for 12, 24 and 48 h.

MAIN OUTCOME MEASURE

Apoptosis based on terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick-end labeling (TUNEL), and semiquantification of Bax and Bcl-2.

RESULTS

No apoptosis was found by TUNEL, Bax and Bcl-2 after 12 h incubation with any progestogen. TUNEL increased after incubation for 24 and 48 h with progesterone 500 ng/mL; LNG 250, 500 ng/mL and all concentrations of MPA (p<.001), Bax increased and Bcl-2 decreased at all concentrations of MPA and the two highest concentrations of LNG at 48 h (p<.05).

CONCLUSION

MPA results in apoptosis of HEECs.

Injectable contraception: what should the longest interval be for reinjections?

BACKGROUND

Progestin-only injectable contraceptives continue to gain in popularity, but uncertainty remains about pregnancy risk among women late for reinjection. The World Health Organization (WHO) recommends a "grace period" of 2 weeks after the scheduled 13-week reinjection. Beyond 2 weeks, however, many providers send late clients home to await menses.

STUDY DESIGN

A prospective cohort study in Uganda, Zimbabwe and Thailand followed users of depot-medroxyprogesterone acetate (DMPA) for up to 24 months. Users were tested for pregnancy at every reinjection, allowing analysis of pregnancy risk among late comers.

RESULTS

The analysis consists of 2290 participants contributing 13,608 DMPA intervals. The pregnancy risks per 100 women-years for "on time" [0.6; 95% confidence interval (CI), 0.33-0.92], "2-week grace" (0.0; 95% CI, 0.0-1.88) and "4-week grace" (0.4; 95% CI, 0.01-2.29) injections were low and virtually identical.

CONCLUSION

Extending the current WHO grace period for DMPA reinjection from 2 to 4 weeks does not increase pregnancy risk and could increase contraceptive continuation.

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.

Effect of Norplant contraceptive on the bones of Nigerian women as assessed by quantitative ultrasound and serum markers of bone turnover

Levonorgestrel is a commonly used progestin-only contraceptive that is available as subdermal (Norplant) and intrauterine implants. Other progestin-only contraceptives such as injectable medroxyprogeterone acetate have been shown to decrease bone mineral density in long-term users. We used calcaneal ultrasound to compare the bone quality of Nigerian women between 25 and 50 years of age who had Norplant implants for 1-4 years to that of women who were not using any form of hormonal contraceptive. The mean stiffness index of women who had Norplant implants for as long as 4 years was not significantly different from that of controls. However, serum markers of bone turnover were significantly decreased in women with Norplant implants compared to age-matched controls. Serum bone-specific alkaline phosphatase was significantly decreased in subjects with Norplant implants for 1 year (13.7+/-6.0 vs. 23.0 U/L for controls, p = .001) and serum NTx was significantly decreased in subjects with implants for 3 years (10.6+/-4.9 vs. 17.6+/-7.7 bone collagen equivalents per liter for controls, p < .001). We conclude that although levonorgestrel contraceptive decreased overall bone turnover, it had no deleterious effect on the bone quality of women using Norplant implants for up to 4 years.

Histological characteristics and altered expression of interleukins (IL) IL-13 and IL-15 in endometria of levonorgestrel users with different uterine bleeding patterns

OBJECTIVE

To determine the relationship between uterine bleeding patterns in levonorgestrel users with endometrial histology and expression of interleukins (IL) IL-13 and IL-15.

DESIGN

Prospective observational study.

SETTING

Academic research center.

PATIENT(S)

Questionnaires were sent to patients (n = 578) who had levonorgestrel implants concerning bleeding patterns; 35 of these patients were identified to have regular cycle (n = 13), amenorrhea (n = 8), or metrorrhagia (n = 14).

INTERVENTION(S)

Endometrial biopsies, serum, histology, and immunostaining.

MAIN OUTCOME MEASURE(S)

Endometrial histological assessment and immunostaining for IL-13 and IL-15 and for blood levonorgestrel, E2, and progesterone levels by ELISA or RIA.

RESULT(S)

No correlation was found between circulating levonorgestrel, E2, or progesterone levels with the bleeding patterns, although a trend toward a lower E2 level was observed in patients with amenorrhea who had inactive endometrium. There was a direct correlation between bleeding patterns and endometrial histology, as well as IL-13 and IL-15 expression in patients with regular cycles and metrorrhagia, demonstrating secretory and proliferative endometrium, respectively. Some patients in each group were also identified as demonstrating endometritis.

CONCLUSION(S)

Endometrial histology may assist directing therapy and subsequently increasing compliance in progestin-only contraceptive users with irregular bleeding who fail to respond to standard therapies. Altered endometrial expression of IL-13 and IL-15, key cytokines in inflammatory and immune cell trafficking, may influence events, leading to irregular bleeding.

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.

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.

Norplant and other implantable contraceptives

Implantable contraception represents a safe, reversible form of long-term family planning with distinct advantages. It does not contain estrogen, thus avoiding many of it contraindications. Importantly, it is extremely effective, has high continuation rates, and is well tolerated. The main side effects of Norplant are irregular menstrual bleeding and the occasional difficult removal. Although recent high-profile litigation has severely diminished enthusiasm for Norplant, the FDA has reaffirmed its safety and efficacy. Norplant remains a viable family planning option for carefully selected women. New contraceptive implants may soon be available accentuating the advantages of Norplant while minimizing the disadvantages.

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.

Adolescents: at increased risk for osteoporosis?

Perhaps the most important factor in the primary prevention of osteoporosis is the attainment of an optimal peak bone during adolescence. In addition to endogenous factors, such as genetic and ethnic background, environmental factors such as dietary habits, physical activity, and sex hormone therapy, influence the accretion of bone mass during this critical period of skeletal growth. First, calcium dietary intake in adolescents is generally well less than the current recommended RDA of 1200 mg/day. Multiple studies of children and adolescents have demonstrated increases in bone mass with dietary calcium supplementation. Second, regarding physical activity, the overall impression is that a moderate amount of particularly weight-bearing exercise has a positive impact on bone. There appears, however, to be a threshold of intensity of physical activity over which a negative impact on bone occurs, particularly when the exercise is of an anaerobic nature or occurring in very thin, amenorrheic participants. Third, previous research suggests that the various forms of hormonal contraception exert differing effects on bone mass in adolescents, with levonorgestrel implants and combined oral contraceptives may be associated with a more positive effect on bone mass compared with that observed with depot medroxyprogesterone acetate. From a clinical perspective, approaches to optimizing peak bone mass in adolescents would include increasing calcium intake, whether in the form of dairy products, fortified foods, or supplements as well as encouraging participation at a moderate level, in weight-bearing exercise. Last, in adolescents with extensive risk factors and predicted long duration of use, subdermal implants or combined oral contraceptives may be the optimal hormonal methods of birth control.

Ovarian function during use of Nestorone(R) subdermal implants

Nestorone(R) progestin (NES) is a potent 19-nor-progesterone derivative which is biologically inactive when administered orally; however, it is an excellent option for implant contraception. The objective of this study was to evaluate ovarian function during use of either one 4-cm or two 3-cm NES implants for 24 months. A total of 60 volunteers were enrolled in each dose group. Vaginal ultrasound (VUS) and blood sampling for determinations of estradiol (E(2)), progesterone (P) and NES serum levels were carried out twice a week for 6 consecutive weeks, beginning in months 1, 6, 12, 18, and 24 of implant use. Serum levels of NES declined with time, with a more pronounced decrease during the first 18 months of implant use; thereafter, NES levels remained stable until the end of the study at 24 months. Luteal activity was very infrequent during the first year of use (<3%) but increased during the second year, occurring in 27% and 35% of the sampling periods in the 1-implant group, and 2% and 16% of the sampling periods in the 2-implant group, at months 18 and 24 of use, respectively. No luteal activity was observed with NES levels above 80 pmol/L. Serum P levels in periods of luteal activity were significantly lower than those of controls. Persistent anovulatory follicles were the most common VUS finding and this was associated with E(2) levels that remained within the normal range (101-1500 pmol/L) in the majority of the sampling periods studied. Considering that a single implant offers advantage for insertion and removal, a new single NES implant is being developed with a slightly higher release rate, to reduce effectively the incidence of ovulation and provide a greater margin of safety beyond 2 years.

Prevalence of enlarged ovarian follicles among users of levonorgestrel subdermal contraceptive implants (Norplant)

OBJECTIVE

The aim of this study was to determine the prevalence of enlarged follicles, as detected by a single clinical or ultrasonographic examination, among users of levonorgestrel subdermal contraceptive implants (Norplant implants).

STUDY DESIGN

This was a cross-sectional study of 103 users of Norplant implants and 50 users of the TCu380A intrauterine contraceptive device, all of whom received reproductive health services from PROFAMILIA, Santo Domingo, Dominican Republic. Bimanual pelvic examination and vaginal ultrasonography were performed. Enlarged follicles (>25 mm) were followed up weekly. The chi(2) test was applied to these data.

RESULTS

Enlarged follicles were detected by ultrasonography in 17. 5% of Norplant implants users and 4% of TCu380A intrauterine contraceptive device users, respectively (P <.04). There was no difference according to duration of use. The longest time to involution of the follicles was 4 weeks. Forty percent of the enlarged follicles detected by ultrasonography were also detected by bimanual pelvic examination.

CONCLUSION

Enlarged follicles are a frequent finding among women who use Norplant implants, but they are less frequent than described in previous studies, which were based on serial ultrasonographic scans in selected groups of users. Physicians and users should be aware of the transient nature of these enlarged follicles, which do not require intervention.

A randomized multicenter study comparing the efficacy and bleeding pattern of a single-rod (Implanon) and a six-capsule (Norplant) hormonal contraceptive implant

To compare the contraceptive efficacy, tolerability, and bleeding patterns, 200 healthy female volunteers received, in an open, comparative, randomized, multicenter study in China, either a single-rod (Implanon) or a six-capsule (Norplant) contraceptive implant for 2 years with an optional extension of up to 4 years. Women were exposed to Implanon for 341.6 woman-years and Norplant for 329.1 woman-years. There were no pregnancies during the study. Per 90-day reference period, the median number of bleeding/spotting days with Implanon decreased from 33.5 in the first period to 19.0-21.5 days in the last year. Similarly, with Norplant, the median number of bleeding/spotting days decreased from 34.5 to 18.0-23.0 days, respectively. The number of bleeding/spotting episodes during year 1 was 2.0 per 90-day reference period with Implanon and 3.0 per period with Norplant (p < 0.05 for periods 1-4). For the remaining 90-day periods, there was no statistical difference between the two groups. In general, there was less frequent bleeding with Implanon compared with Norplant, whereas the incidences of amenorrhea and infrequent bleeding were higher with Implanon than with Norplant. The mean overall incidence of prolonged bleeding fell markedly during the study, from 66.0% in reference period 1 to 27.3% in period 16 with Implanon and from 69.0% to 21.7% with Norplant, respectively. The most common adverse events were related to disturbed bleeding patterns, which were also the major reasons for discontinuation (Implanon n = 8; Norplant n = 14). Normal menses returned in almost all subjects within 3 months after removal of the implants. Implanon was inserted in a mean time of 0.61 min and Norplant in 3.90 min (p < 0.001). Similarly, the mean time required to remove the implant was significantly shorter for Implanon than for Norplant (2.18 min vs 11.25 min, p < 0.001). The maximum time required for removal of the implant was 10 min for the Implanon group and 60 min for the Norplant group. In both groups, blood pressure and hemoglobin were not affected, whereas body weight tended to increase. It can be concluded that both contraceptive systems demonstrated excellent contraceptive efficacy and were well tolerated. Compared with Norplant, there was less frequent bleeding with Implanon, whereas the incidence of infrequent bleeding and amenorrhea was higher. Implanon was significantly quicker to insert and to remove than was the multiple capsule system.

Timing of onset of contraceptive effectiveness in Norplant implant users. II. Effect on the ovarian function in the first cycle of use

The objective of this study was to time the onset of contraceptive effectiveness in Norplant implant users, when the capsules were inserted beyond the first 7 days of the cycle, based on the immediate effect on the ovarian activity. A total of 42 healthy women requesting Norplant implant contraception were enrolled at clinics in Santo Domingo, Dominican Republic, and in Baltimore, Maryland. Implants were inserted on days 8-13 of the menstrual cycle. Blood samples for estradiol (E2), progesterone (P), luteinizing hormone (LH) (in a subset of 12 women), and levonogestrel (LNG) assay, were taken at 0 h and at 6, 12, 24, 72, and 168 h postinsertion. Ovulation, as defined by P > 2.5 ng/mL, occurred in 40% of subjects. A short lasting, frequently blunted, LH peak occurred within 12 h postinsertion, in all these subjects. The remaining subjects had anovulatory cycles with two distinct E2 profiles: continuously increasing E2 levels to a high mean of 414.3 pg/mL (28%), or no sustained increase in E2 (32%). Most cycles (86%) in which Norplant was inserted with high E2 levels (> 175 pg/mL) were ovulatory, whereas none were ovulatory with low E2 (< 100 pg/mL) at insertion. Based on the endocrine effects of Norplant implant insertion in the midadvanced follicular phase, in which ovulation will either occur within 48 h of insertion or will be impaired, additional contraceptive protection is necessary only for 3 days.

Effects of hormonal contraceptives on bone mineral density

The clinical research to date on the effects of 3 types of hormonal contraceptives, i.e. depot medroxyprogesterone acetate ('Depo-Provera'), levonorgestrel subdermal implants ('Norplant'), and oral contraceptives, on bone mineral density in premenopausal women is reviewed. The large variance in results across studies for each method is in part due to differences in research design, techniques for measuring bone mineral density, age of the study participants and type of oral contraceptive preparation. However, the balance of the evidence leans toward a positive effect of oral contraceptives on bone mineral density in women of all age. On the other hand, few observations have yet been published on the effects of the new progestin oral contraceptives on bone mineral density. The few extant data suggest a positive impact of levonorgestrel subdermal implants on bone mineral density in women of all ages. Although the findings are preliminary, it appears that depot medroxyprogesterone acetate may exert a negative effect on bone mineral density. More specifically, caution should be exercised in prescribing long term depot medroxyprogesterone acetate (e.g. > 5 years) especially in young adolescents (e.g. < 16 years old) who may not have yet reached peak bone mass.

Norplant consensus statement and background review

This review has highlighted the attributes of a very important new method of contraception. The signatories to this document agree that, with the provision of appropriate information and instruction for the user, Norplant is a good contraceptive choice to be made available worldwide in family planning programs that have the resources for appropriate training and counseling. The signatories to this document are acting in their own personal capacity and not as representatives of any particular organization.

The pediatrician and the sexually active adolescent. Sexual activity and contraception

Sexuality and its resultant consequences continue to be major issues for adolescents and for those who provide their health care. This article discusses current sexual behavior in adolescents and describes the various forms of hormonal contraception that sexually active adolescents should use.

Neuroendocrine mechanism of anovulation in users of contraceptive subdermal implant of nomegestrol acetate (Uniplant)

OBJECTIVE

To evaluate a nomegestrol acetate subdermal contraceptive implant's (Uniplant; Thermex, Monaco) effect on the hypothalamus-pituitary-ovarian axis.

DESIGN

A prospective clinical trial.

SETTING

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

PATIENT(S)

Normally cycling healthy women.

INTERVENTION(S)

Insertion of Uniplant.

MAIN OUTCOME MEASURE(S)

Luteinizing hormone pulse and endocrine profiles were assessed before, 48 hours after insertion, and after prolonged use of the implant.

RESULT(S)

Anovulation was noted in 100% of users in the first month. Seventy percent of subjects demonstrated follicular development with the absence of ovulation and an endocrine profile similar to the follicular phase: (LH pulse/8 hours 6.85 +/- 0.67, LH amplitude 3.54 +/- 0.65 mIU/mL (conversion factor to SI unit, 1.00), and E2 193 +/- 29.4 pg/mL (conversion factor to SI unit, 3.67), whereas 30% demonstrated no follicular activity with an endocrine profile similar to the luteal phase: (LH pulse/8 hours; 3.66 +/- 0.66, LH amplitude 5.76 +/- 1.73 mIU/mL, and E2 67.5 +/- 4 pg/mL. Clinical characteristics, serum gonadotropin concentration, and LH pulse characteristics failed to predict which subjects would initiate or remain devoid of follicular activity.

CONCLUSION(S)

Uniplant results in anovulation via two mechanisms: hypothalamic suppression in subjects who lack follicular development, and likely suppression of the pituitary LH surge in subjects who initiate follicular activity.

Ultrasonographic and endocrine evaluation of ovarian function among Norplant implants users with regular menses

With the objective of evaluating the ovulatory function among long-term Norplant implants users with regular menstrual cycles, we undertook this prospective study including 11 Norplant implants users and 11 control women who were not using hormonal methods of fertility control. Exposed and unexposed women had had at least three regular menstrual cycles preceding enrollment. All women were followed during one menstrual cycle by serial vaginal ultrasound and estradiol (E2), progesterone (P), LH, and FSH measurements. Three Norplant implants users ovulated, three had luteinization of an unruptured follicle (LUF), three had persistent follicle growth up to a mean of 33 mm without rupture, and two had no follicular development beyond 16 mm. Ten of the controls had normal ovulation and one had LUF. Mean peak LH and FSH among Norplant implants users who ovulated were three- to four-fold lower than among controls. Although users of Norplant implants with regular cycles frequently have luteal activity, the results of this study suggest that elevation of P during the second half of the cycle does not necessarily indicate ovulation has occurred and may frequently be associated with the presence of luteinized unruptured follicle. When ovulation occurs, there are usually abnormal hormone levels (low LH/FSH peak, low progesterone) which may also contribute to the contraceptive effect of Norplant implants.

A prospective comparison of bone density in adolescent girls receiving depot medroxyprogesterone acetate (Depo-Provera), levonorgestrel (Norplant), or oral contraceptives

OBJECTIVE

To examine bone density among adolescents receiving different forms of hormonal contraception along with that of control subjects.

METHODS

Baseline and 1-year measures of lumbar vertebral bone density were obtained in girls receiving depot medroxyprogesterone acetate (Depo-Provera) (n = 15), levonorgestrel (Norplant) (n = 7), or oral contraceptives (n = 9) and in girls receiving no hormonal treatment (n = 17). In a subsample of Depo-Provera users (n = 8), Norplant users (n = 3), and control subjects (n = 4), bone density measurements were repeated after 2 years. Bone density was measured by dual-energy x-ray absorptiometry.

RESULTS

Body mass indexes, level of pubertal development, substance use, and reproductive histories were not significantly different among the groups. More black girls were represented in the initial Depo-Provera group (p < 0.02), girls in the Norplant group exercised more hours per week (p < 0.02), and control subjects were older (p < 0.01) than those in the other groups. These variables did not significantly affect bone density results. After 1 year, bone density decreased 1.5% in Depo-Provera users, compared with increases of 2.5% in Norplant users, 1.5% in oral contraceptive users, and 2.9% control subjects (p < 0.02). After 2 years, bone density increased a total of 9.3% in Norplant users and 9.5% in control subjects but decreased a total of 3.1% in Depo-Provera users (p < 0.0001).

CONCLUSION

These data suggest that Depo-Provera may, at least temporarily, suppress the expected skeletal bone mineralization in adolescents, whereas Norplant and oral contraceptives are associated with the expected increase in bone density in this population.

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.

Effect of preovulatory insertion of Norplant implants over luteinizing hormone secretion and follicular development

OBJECTIVE

To determine whether the process of ovulation could be interrupted by the insertion of Norplant implants (Leiras Pharmaceuticals, Turku, Finland) in the advanced preovulatory phase.

DESIGN

Prospective study.

SETTING

The Department of Biomedical Research at the Family Planning Clinic of PROFAMILIA, Santo Domingo, Dominican Republic.

PATIENTS

Healthy women of reproductive age, requesting Norplant implants contraception. Thirteen of 15 women volunteers who were admitted completed the study.

INTERVENTIONS

Norplant implants were inserted when the dominant follicle reached a mean diameter of 16 mm, based on serial vaginal ultrasounds (US) beginning on day 10 of the cycle. Blood samples for determination of E2, P, LH, and levonorgestrel, were taken and vaginal US performed at 0, 4, 24, 48, and 72 hours after insertion. If follicle rupture had not occurred at 72 hours after insertion, blood sampling and US were done three times per week during 2 additional weeks.

RESULTS

Follicle rupture occurred in 11 of 13 subjects within 72 hours after insertion, with the exception of 1 subject in whom rupture occurred between 72 and 192 hours. Two women already had an LH peak at the time of insertion. In 9 of the remaining 11 women, a shortlasting, blunted LH surge was observed at 4 hours postinsertion. In the remaining two women, who had the lowest E2 levels, ovulation was inhibited, and a persistent follicle developed without luteinization.

CONCLUSIONS

The insertion of Norplant implants in the advanced follicular phase will not inhibit ovulation if sufficient E2 priming has occurred. On the contrary, the exogenous progestin may rapidly foster ovulation shortly after.

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

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

Effect of levonorgestrel-releasing intrauterine device on hormonal profile and menstrual pattern after long-term use

In the present study 14 women after 6 years' use of levonorgestrel-releasing IUD were investigated for the changes of LH, progesterone (P), estradiol (E2), prolactin (PRL) and serum binding globulin (SHBG) in relation to the levonorgestrel levels throughout a segment of 26-40 days with the aim of comparing the hormonal profiles with those during the first year of use of Lng-IUD. Ultrasound scanning was used to follow the development of follicles along with the RIA measurement of hormones. The results of serum LH, P and E2 showed ovulation in 11 cases with either normal menstrual cycles (5 cases), prolonged or irregular cycles (4 cases) or with amenorrhea for 2-3 years (2 cases). One case showed insufficiency of luteal function and 2 cases showed anovulation but with follicular hyperactivity. Higher percentages of ovulatory cycles (78.5%) were found after 6 years of use. No case of complete suppression of ovulation was found. Anovulatory cycles only constituted 14.3%. Clinically, the development of follicles followed by ultrasound scanning further confirmed the hormonal findings. The persistent enlargement of follicles coincided with high levels of E2. After 6 years of use, the serum levels of levonorgestrel were still maintained at mean levels of 314.26 pmol/L and 470.63 pmol/L in the ovulatory and anovulatory groups, respectively. It is concluded that over two-thirds of the cases have ovulatory cycles after long-term use of Lng-IUD; the contraceptive effect is mainly due to its local action on the endometrium, with much less effect on the ovarian function.

Hormonal implants: contraception for a new century

Subdermal implants are contraceptive systems that release low, stable amounts of synthetic progestins from Silastic or other materials for periods of months to several years. Unlike other hormonal delivery systems, they do not cause unnecessary peaks in progestin levels and do not use estrogens, and thus their health risks are minimal. Norplant has been studied more extensively than any other subdermal contraceptive implant. More than 60,000 women have participated in clinical trials, which demonstrated that this approach is one of the most effective reversible contraceptive methods available (1% pregnancy rate in 5-year users). The implant also reduces the incidence of ectopic pregnancy to a level much below noncontraceptive users and about equivalent to TCu380A intrauterine device users. Exposure to the sustained, low dose of levonorgestrel delivered by Norplant has shown only minor metabolic changes. Side effects are minor but often bothersome, causing some discontinuation of the method. First-year continuation rates range from 76% to 90%. Fertility return after discontinuation is prompt. Difficulty in removal of the implant capsules by the less experienced practitioner has motivated researchers to develop systems that are easier to use, less obvious under the skin, and biodegradable. The Norplant 2 system is faster, easier, and less painful to insert and remove. Implants under investigation release desogestrel and other progestins; Capronor and subdermal norethindrone pellets are biodegradable systems.

Advances in Hormonal Contraception

Breakthroughs involving innovative methods of hormonal and nonhormonal birth control have been severely limited in the United States over the last 30 years. This trend has changed with the introduction of new choices in birth control in the 1990s. This article focuses on these advances in hormonal contraception and provides information on the use of oral contraceptives, hormonal implants, and injectable methods of contraception currently available in the United States. Each method is assessed and recommendations are made for proper patient and method selection. This information is intended to supply the pharmacist with sufficient information to appropriately counsel patients on the use of hormonal contraception in the 1990s.

NORPLANT: levonorgestrel-releasing contraceptive implant

NORPLANT is the newest contraceptive system to be introduced world-wide, with nearly a million current users. It consists of six Silastic capsules containing levonorgestrel (LNg), which are inserted under the skin in the arm. Release of the steroid commences immediately so that, after several weeks, circulating levels of LNg stabilize between 0.3 and 0.4 ng/ml of plasma, and they persist elevated with a minor decline for over 5 years. The gross cumulative pregnancy rate at 5 years is 2.6 per 100 woman-years. In the majority of women it produces no abnormalities in a variety of clinical chemistry, metabolic, haematological and coagulation parameters. The most common side-effect is disruption of the menstrual bleeding pattern; this is reported by two-thirds of the users in the first months and by one-third by the fifth year. Because it is the most disturbing side-effect for many users, counselling prior to insertion is of paramount importance. NORPLANT exerts varying degrees of gonadotrophin and ovarian inhibition, including anovulation and luteal insufficiency. Endometrial development is irregular and, irrespective of oestrogen levels, cervical mucus is thick and scanty at all times due to the strong antioestrogenic effect of LNg. Inhibition of sperm penetration fully accounts for the antifertility effect of NORPLANT in ovulatory cycles. The high contraceptive efficacy, lack of serious side-effects, reversibility and the convenience of long-term unattended use explain the high acceptability of NORPLANT.

Free levonorgestrel index and its relationship with luteal activity during long-term use of Norplant implants

Levonorgestrel serum levels and sex hormone binding globulin (SHBG) were measured in 82 women during different years of use of Norplant implants. The ratio between levonorgestrel and SHBG was calculated as an indicator of the free biologically active fraction of levonorgestrel (free levonorgestrel index, FLI). These parameters were then correlated with the presence of luteal activity, as determined by progesterone levels above 9.6 nmol/L, in a sampling run of 10 samples taken twice a week for five consecutive weeks. Levonorgestrel serum levels remained constant around 1.0 nmol/L during the five-year period. SHBG levels were below normal for the first 18 months of use, returning to normal levels during the last three years of use. The FLI in the first two years was significantly higher than that observed in the later years. The frequency of cycles with luteal activity was 12% during the first 2 years, increasing to 44% in the latter years, when FLI levels were lower. Our results suggest that the changes in SHBG and consequently in the free biologically active fraction of levonorgestrel may largely account for the differences in degree of ovarian suppression observed between the first two years of use of Norplant implants and the latter three, even in the absence of a significant variation in total levonorgestrel concentrations.

A review of the effects of long-acting progestogen-only contraceptives on ovarian activity

Progestogen-only contraception acts mainly by blocking cervical mucus and preventing sperm penetration through it does have a variable pattern of contraceptive effects on the endometrium and ovary. In contrast with the complete suppression of ovarian function with combined pill or injectable use, a variable degree of endocrine activity is demonstrated in women choosing a long-acting progestogen-only contraceptive. This degree of suppression of ovarian activity explains the decrease in systemic side-effects, the rapid resumption of ovulation and recovery of fertility following the discontinuation of the method. New delivery systems of progestogens, the vaginal ring and implant, offer better and more consistent contraceptive effects.

Hormonal changes associated with bleeding during low dose progestogen contraception delivered by Norplant subdermal implants

The main side effect associated with the use of Norplant contraceptive implants is a disruption of the menstrual bleeding pattern. To explore the relationship between bleeding and hormonal changes, we analyzed the estradiol (E2) and progesterone (P) patterns that preceded bleeding episodes or that corresponded to periods of amenorrhea in 103 cycles observed among 82 women using Norplant subdermal implants. Five different bleeding patterns were defined: 'normal' (24-45 day cycles), oligomenorrhea (46-90 day cycles), amenorrhea (over 90 day cycles), irregular/frequent bleeding (less than 25 day cycles), and prolonged bleeding (continuous bleeding/spotting for more than 10 days). All 'normal' cycles were associated with a rise followed by a fall in E2 levels preceding bleeding. In half of the 'normal' cycles (28/54), a rise and fall of P was also observed. The same pattern was found in oligomenorrheic cycles, but only two of 12 cycles had a rise and fall of both E2 and P. None of the subjects with amenorrhea had luteal activity. Six of the nine amenorrheic cycles displayed persistently low E2 levels (below 75 pg/ml). The remaining three had a moderate elevation in E2 levels during the sampling period. Sixty percent of the subjects who showed irregular/frequent bleeding (15/25) had low E2 levels (less than 75 pg/ml), without luteal activity, and bleeding occurred without clear evidence of a further drop in E2 levels. In the remaining 40%, bleeding was preceded by a rise and drop of E2 without luteal activity, with the exception of one women, who exhibited a rise and fall of both E2 and P. Samples were obtained in only three subjects during continuous bleeding. One had low E2 levels, and the remaining two bled continuously, in spite of having E2 levels in the normal range. We conclude that ovarian hormones continue to influence endometrial shedding during the use of Norplant contraceptive implants.