Efficacy, bleeding patterns, and side effects of a 1-year contraceptive vaginal ring

Vaginal ring acceptability: A systematic review and meta-analysis of vaginal ring experiences from around the world

OBJECTIVE

The vaginal ring (ring) is a female-initiated, long-acting drug delivery system for different indications, including HIV prevention. Our aim was to provide evidence for acceptability of the vaginal ring across indications to support dapivirine and multipurpose prevention technology ring introduction and roll out.

STUDY DESIGN

This systematic review and meta-analysis followed PRISMA guidelines. We searched PubMed, Web of Science, Embase, and grey literature for publications reporting favorable ring acceptability and secondary outcomes involving actual ring use (comfort, ease of ring use, ring comfort during sex, expulsions, and vaginal symptoms) or hypothetical acceptability for any indication published January 1, 1970-June 15, 2021. We estimated random-effects pooled prevalence, assessing between-study variation using meta-regression.

RESULTS

Of 2,234 records, we included 123 studies with 40,434 actual and hypothetical ring users. The primary outcome assessment included 50 studies with 60 ring subgroups totaling 19,271 ring users. The favorable acceptability pooled prevalence was 85.6% (95%CI 81.3, 89.0), while hypothetical acceptability among non-ring users was 27.6% (95%CI 17.5, 40.5). In meta-regression, acceptability was higher in menopause (95.4%; 95%CI 88.4, 98.2) compared to contraceptive rings (83.7%; 95%CI 75.6, 89.5). Acceptability was lower in pharmacokinetic studies (50%; 95%CI 22.1, 77.9) compared to RCTs (89.5%; 95%CI 85.8.92.4) and in studies assessing acceptability at ≥12 months (78.5%; 95%CI 66.5, 87.1) versus studies assessing acceptability at <3 months (91.9%; 95%CI 83.7, 96.1). European (90.6%; 95%CI 83.9, 94.7), Asian (97.1%; 95%CI 92.0, 99.0), and multi-region studies (93.5%; 95%CI 84.6, 97.4) reported more favorable acceptability compared to African studies (59.4%; 95%CI 38.3, 77.5). Secondary outcomes were similarly favorable, including ring comfort (92.9%; 95%CI 89.2, 95.4), ease of use (90.9%; 95%CI 86.5, 94.0), and comfort during sex (82.7%; 95%CI 76.4, 87.6). Limitations include inconsistent outcome definitions and unmeasured factors affecting acceptability.

CONCLUSIONS

Women who used vaginal rings reported they were acceptable across indications geographic regions and indications. Policy makers should consider the ring as an important option for pregnancy and HIV prevention drug development.

IMPLICATIONS

This review found favorable acceptability among vaginal ring users across indications and geographic areas, in contrast to low hypothetical acceptability among non-users. Vaginal rings are an important drug delivery system for pregnancy and HIV preventions, and scale-up should plan to address initial hesitancy among new users.

Single-dose pharmacokinetics and pharmacodynamics assessment of oestriol and trimegestone containing vaginal rings in healthy women with childbearing potential

PURPOSE

To evaluate the pharmacokinetics and pharmacodynamics of oestriol (E3) and trimegestone (TMG) in healthy women after application of three different vaginal rings over 21 days. The vaginal rings had a nominal delivery rate of 0.413/0.050 mg/day (Test 1), 0.311/0.090 mg/day (Test 2) and 0.209/0.137 mg/day (Test 3) E3/TMG.

METHODS

Thirty-five healthy women were randomised to receive a single application of Test 1, 2 or 3 (Clinical Trial NCT03343912). The E3 and TMG plasma concentration was determined by LC-MS/MS. Oestradiol (E2) and progesterone (PG) serum concentrations, and bleeding patern were determined as pharmacodynamic parameters. Safety was assessed by evaluation of adverse events and local tolerability.

RESULTS

The total and maximum exposure of E3 and TMG increased in a proportional ratio to dose. However, not in a magnitude which was expected from the dose differences for E3. During Test 2 and 3 treatment all E2 and PG values remained on a well suppressed level until end of treatment. E2 and PG serum levels increased distinctly earlier after ring removal with Test 1 compared to Test 2 and 3. Test 3 achieved 95.24% of "no bleeding" days under treatment followed by Test 1 (91.67%), and Test 2 (86.15%).

CONCLUSIONS

The Test 3 formulation presented the best dose combination of E3/TMG for contraception. Moreover, all vaginal rings were well tolerated.

Vaginal ring acceptability and related preferences among women in low- and middle-income countries: A systematic review and narrative synthesis

The vaginal ring (VR) is a female-initiated drug-delivery platform used for different indications, including HIV pre-exposure prophylaxis (PrEP). We conducted a systematic review of VR acceptability, values and preferences among women in low- and middle-income countries (LMIC) to inform further investment and/or guidance on VR use for HIV prevention. Following PRISMA guidelines, we used structured methods to search, screen, and extract data from randomized controlled trials (RCTs) and observational studies reporting quantitative outcomes of acceptability of the VR for any indication published 1/1970-2/2019 (PROSPERO: CRD42019122220). Of 1,110 records identified, 68 met inclusion criteria. Studies included women 15-50+ years from 25 LMIC for indications including HIV prevention, contraception, abnormal bleeding, and menopause. Overall VR acceptability was high (71-98% across RCTs; 62-100% across observational studies), with 80-100% continuation rates in RCTs and favorable ease of insertion (greater than 85%) and removal 89-99%). Users reported concerns about the VR getting lost in the body (8-43%), although actual expulsions and adverse events were generally infrequent. Most women disclosed use to partners, with some worrying about partner anger/violence. The VR was not felt during intercourse by 70-92% of users and 48-97% of partners. Acceptability improved over time both within studies (as women gained VR experience and worries diminished), and over chronological time (as the device was popularized). Women expressed preferences for accessible, long-acting, partner-approved methods that prevent both HIV and pregnancy, can be used without partner knowledge, and have no impact on sex and few side effects. This review was limited by a lack of standardization of acceptability measures and study heterogeneity. This systematic review suggests that most LMIC women users have a positive view of the VR that increases with familiarity of use; and, that many would consider the VR an acceptable future delivery device for HIV prevention or other indications.

Comparative randomized study on the sexual function and quality of life of women on contraceptive vaginal ring containing ethinylestradiol/etonogestrel 3.47/11.00mg or 2.7/11.7mg

The objective of the study was to evaluate the sexual function and quality of life (QoL) of healthy women on a new contraceptive vaginal ring (CVR) containing ethinylestradiol (EE) 3.47 mg and etonogestrel (ENG) 11.00 mg (study group) manufactured with a new polymer composition compared to EE 2.7 mg/ENG11.7 mg CVR (control group). Fifty-eight women were randomly allocated to the study group and the control group. The Female Sexual Function Index (FSFI), the Female Sexual Distress Scale (FSDS) and the Short Form-36, were used to assess sexual function, sexual distress and QoL, respectively. The study included two follow-ups, at 90 days and at 180 days. The control group reported more adverse events, mainly breakthrough bleeding, than the study group. The sexual function scores in the women in the study group improved with respect to those of the control group both at the 1st (FSFI, p = .009; FSDS, p = .001) and at the 2^nd (FSFI, p = .001; FSDS, p = .002) follow-up. QoL of the study group improved at the 1^st follow-up (p < .05) and 2^nd (p < .01) follow-up. The control group improved their QoL at the 2nd follow-up (p < .01). The more gradual EE release of the new polymer composition could justify the behavioral differences of the women of the two groups.

Advances in contraceptive vaginal rings: what does the future hold?

INTRODUCTION

Contraceptive vaginal rings (CVRs) are good contraceptive options because they do not require skilled providers, are self-administered, and show a higher stability of drug diffusion.

AREAS COVERED

This article provides a review of the developments made with CVRs over the past number of years, while giving focus to the latest CVRs that have gone through clinical development. The author of the article also provides an expert perspective on the future of these useful therapeutic options.

EXPERT OPINION

Pharmacokinetic studies have shown that segesterone, an absorbable progestin that is used alone or in combination with ethinyl estradiol (EE) or E_2, is the CVR of choice at this present time. Indeed, segesterone has demonstrated safety and efficacy as a CVR and is also an appropriate option for lactating women, as they are not absorbed orally. However, good cycle control is important for improved CVR adherence. CVRs that allow the combination of more than one drug may unravel another multi-purpose use when combined with microbicides and could provide combined protection to women who wish to protect themselves from pregnancy and sexually transmitted infection.

Pharmacokinetic bioequivalence, safety and acceptability of Ornibel®, a new polymer composition contraceptive vaginal ring (etonogestrel/ethinylestradiol 11.00/3.474 mg) compared with Nuvaring® (etonogestrel/ethinylestradiol 11.7/2.7 mg)

OBJECTIVE

To show the clinical development of Ornibel^® (ExeltisHealthcare, Spain) a contraceptive vaginal ring manufactured with a new polymer composition and containing etonogestrel/ethinylestradiol, compared to Nuvaring^® (MSD, Spain).

SUBJECTS AND METHODS

Randomised, single dose, 2-period, 2-sequence, 2-stage crossover, comparative bioavailability study conducted in 40 healthy female subjects. All subjects received both treatments for 28 days in each of two periods, separated by a 28 days washout. Ornibel^® contains etonogestrel/ethinylestradiol 11.00/3.47 mg and Nuvaring^® contains etonogestrel/ethinylestradiol 11.7/2.7 mg, both rings delivering 120/15 µg/day. For the calculation of pharmacokinetic parameters, 37 blood samples were collected up to 840 h after each ring insertion to quantify plasma concentrations of etonogestrel and ethinylestradiol using a validated MS/MS-HPLC. Safety was assessed by adverse events recording, clinical laboratory and vital signs and tolerability by vaginal examination. Acceptability was investigated by a 5-point scale questionnaire.

RESULTS

Bioequivalence was demonstrated in the first stage as the 94.12% Confidence Intervals of the primary parameters laid within the 80-125% acceptance range for both etonogestrel (C_max: 96.81-112.20%; AUC_0-504h: 98.71-108.61%; AUC_0-t: 100.14-109.10%) and ethinylestradiol. (C_max: 105.91-120.62%; AUC_0-504h: 105.47-114.59%; AUC_0-t: 108.31-117.61%). During the first day of use a burst effect was observed with Nuvaring^®, with significantly higher level of ethinylestradiol (C_max0-24h ratio: 78.34%, 94.12CI: 73.55-83.45%). Both products were well tolerated and accepted, without significant differences between them.

CONCLUSION

Ornibel^® is bioequivalent to Nuvaring^® in terms of efficacy, safety, tolerability and acceptability. The new polymer composition provides Ornibel^® with more stability and gradual hormonal release during the first day of use, particularly for ethinylestradiol.

Hormonal contraceptives for contraception in overweight or obese women

BACKGROUND

Obesity has reached epidemic proportions around the world. Effectiveness of hormonal contraceptives may be related to metabolic changes in obesity or to greater body mass or body fat. Hormonal contraceptives include oral contraceptives (OCs), injectables, implants, hormonal intrauterine contraception (IUC), the transdermal patch, and the vaginal ring. Given the prevalence of overweight and obesity, the public health impact of any effect on contraceptive efficacy could be substantial.

OBJECTIVES

To examine the effectiveness of hormonal contraceptives in preventing pregnancy among women who are overweight or obese versus women with a lower body mass index (BMI) or weight.

SEARCH METHODS

Until 4 August 2016, we searched for studies in PubMed (MEDLINE), CENTRAL, POPLINE, Web of Science, ClinicalTrials.gov, and ICTRP. We examined reference lists of pertinent articles to identify other studies. For the initial review, we wrote to investigators to find additional published or unpublished studies.

SELECTION CRITERIA

All study designs were eligible. The study could have examined any type of hormonal contraceptive. Reports had to contain information on the specific contraceptive methods used. The primary outcome was pregnancy. Overweight or obese women must have been identified by an analysis cutoff for weight or BMI (kg/m(2)).

DATA COLLECTION AND ANALYSIS

Two authors independently extracted the data. One entered the data into RevMan and a second verified accuracy. The main comparisons were between overweight or obese women and women of lower weight or BMI. We examined the quality of evidence using the Newcastle-Ottawa Quality Assessment Scale. Where available, we included life-table rates. We also used unadjusted pregnancy rates, relative risk (RR), or rate ratio when those were the only results provided. For dichotomous variables, we computed an odds ratio with 95% confidence interval (CI).

MAIN RESULTS

With 8 studies added in this update, 17 met our inclusion criteria and had a total of 63,813 women. We focus here on 12 studies that provided high, moderate, or low quality evidence. Most did not show a higher pregnancy risk among overweight or obese women. Of five COC studies, two found BMI to be associated with pregnancy but in different directions. With an OC containing norethindrone acetate and ethinyl estradiol (EE), pregnancy risk was higher for overweight women, i.e. with BMI ≥ 25 versus those with BMI < 25 (reported relative risk 2.49, 95% CI 1.01 to 6.13). In contrast, a trial using an OC with levonorgestrel and EE reported a Pearl Index of 0 for obese women (BMI ≥ 30) versus 5.59 for nonobese women (BMI < 30). The same trial tested a transdermal patch containing levonorgestrel and EE. Within the patch group, obese women in the "treatment-compliant" subgroup had a higher reported Pearl Index than nonobese women (4.63 versus 2.15). Of five implant studies, two that examined the six-capsule levonorgestrel implant showed differences in pregnancy by weight. One study showed higher weight was associated with higher pregnancy rate in years 6 and 7 combined (reported P < 0.05). In the other, pregnancy rates differed in year 5 among the lower weight groups only (reported P < 0.01) and did not involve women weighing 70 kg or more.Analysis of data from other contraceptive methods indicated no association of pregnancy with overweight or obesity. These included depot medroxyprogesterone acetate (subcutaneous), levonorgestrel IUC, the two-rod levonorgestrel implant, and the etonogestrel implant.

AUTHORS' CONCLUSIONS

The evidence generally did not indicate an association between higher BMI or weight and effectiveness of hormonal contraceptives. However, we found few studies for most contraceptive methods. Studies using BMI, rather than weight alone, can provide information about whether body composition is related to contraceptive effectiveness. The contraceptive methods examined here are among the most effective when used according to the recommended regimen.We considered the overall quality of evidence to be low for the objectives of this review. More recent reports provided evidence of varying quality, while the quality was generally low for older studies. For many trials the quality would be higher for their original purpose rather than the non-randomized comparisons here. Investigators should consider adjusting for potential confounding related to BMI or contraceptive effectiveness. Newer studies included a greater proportion of overweight or obese women, which helps in examining effectiveness and side effects of hormonal contraceptives within those groups.

Efficacy of combined hormonal vaginal ring in comparison to combined hormonal pills in heavy menstrual bleeding

OBJECTIVE

To compare the efficacy, acceptability and compliance of combined hormonal vaginal ring (CVR), with combined hormonal pills (CHP) in patients with heavy menstrual bleeding (HMB).

STUDY DESIGN

This prospective study was conducted in 50 women with HMB in age group of 25-40 years. Patients were divided in two groups of 25 each and followed for six treatment cycles. In each group, cycle comprised of three weeks of CVR (releases 15μg of EE and 120μg of the etonogestrel per day) or CHP (containing 30μgm of EE and 150μgm of LNG) use, followed by one ring or pill free week. After each cycle, patients were evaluated about the amount of blood loss and duration of bleeding by the pictoral blood assessment chart (PBAC), early bleeding (EWB), continued bleeding (CWB), intermenstrual bleeding, intended bleeding, compliance, and user acceptability. The collected data were analyzed using the Chi square test, t-test and ANOVA test.

RESULT

Reduction in PBAC score for CVR (70.73%) and CHP group (70.02%), duration of bleeding and incidence of EWB was comparable among the two groups. The incidence of intermenstrual bleeding was lower in CVR than in CHP group in cycle 3 and 4 with significant p value. The incidence of CWB was significantly lower and the incidence of intended bleeding pattern in CVR group was significantly higher in cycle 3, 4, 5 and 6, signifying better cycle control. Compliance was also higher in CVR (88%) than CHC (75.33% of all cycles).

CONCLUSION

This trial suggests that both the CVR and CHP are very effective short-term treatments for HMB in reproductive age group. However, women had better cycle control and compliance with CVR. This may be an attractive option among the wide variety of medications used to treat HMB.

A temperature-monitoring vaginal ring for measuring adherence

BACKGROUND

Product adherence is a pivotal issue in the development of effective vaginal microbicides to reduce sexual transmission of HIV. To date, the six Phase III studies of vaginal gel products have relied primarily on self-reporting of adherence. Accurate and reliable methods for monitoring user adherence to microbicide-releasing vaginal rings have yet to be established.

METHODS

A silicone elastomer vaginal ring prototype containing an embedded, miniature temperature logger has been developed and tested in vitro and in cynomolgus macaques for its potential to continuously monitor environmental temperature and accurately determine episodes of ring insertion and removal.

RESULTS

In vitro studies demonstrated that DST nano-T temperature loggers encapsulated in medical grade silicone elastomer were able to accurately and continuously measure environmental temperature. The devices responded quickly to temperature changes despite being embedded in different thickness of silicone elastomer. Prototype vaginal rings measured higher temperatures compared with a subcutaneously implanted device, showed high sensitivity to diurnal fluctuations in vaginal temperature, and accurately detected periods of ring removal when tested in macaques.

CONCLUSIONS

Vaginal rings containing embedded temperature loggers may be useful in the assessment of product adherence in late-stage clinical trials.

Efficacy, user acceptability, tolerability, and cycle control of a combined contraceptive vaginal ring: the Indian perspective

OBJECTIVE

To assess the contraceptive efficacy, user acceptability, cycle control, and tolerability of a combined contraceptive vaginal ring for up to 13 cycles.

MATERIALS AND METHODS

Healthy women coming to the OPD for contraceptive advice were enrolled in this one-year study. Each ring was used for three weeks followed by a one-week ring-free period.

RESULTS

A total of 184 women started treatment forming the intent to treat population. Subjects were followed for 13 cycles. Compliance was good with 99 % of cycles in full compliance with specified criteria. In the intent to treat population, no pregnancies occurred giving a Pearl Index of 0. The mean incidence of withdrawal bleeding was 99 % in all cycles. There was 0.16 % incidence of intermenstrual bleeding and 2 % incidence of early withdrawal bleeding. The ring was well tolerated with a low incidence of adverse events.

CONCLUSION

The ring is an effective contraceptive that is convenient, well tolerated with excellent cycle control, and highly acceptable to users.

Diabetes and pregnancy: an endocrine society clinical practice guideline

OBJECTIVE

Our objective was to formulate a clinical practice guideline for the management of the pregnant woman with diabetes.

PARTICIPANTS

The Task Force was composed of a chair, selected by the Clinical Guidelines Subcommittee of The Endocrine Society, 5 additional experts, a methodologist, and a medical writer.

EVIDENCE

This evidence-based guideline was developed using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system to describe both the strength of recommendations and the quality of evidence.

CONSENSUS PROCESS

One group meeting, several conference calls, and innumerable e-mail communications enabled consensus for all recommendations save one with a majority decision being employed for this single exception.

CONCLUSIONS

Using an evidence-based approach, this Diabetes and Pregnancy Clinical Practice Guideline addresses important clinical issues in the contemporary management of women with type 1 or type 2 diabetes preconceptionally, during pregnancy, and in the postpartum setting and in the diagnosis and management of women with gestational diabetes during and after pregnancy.

Hormonal contraceptives for contraception in overweight or obese women

BACKGROUND

Obesity has reached epidemic proportions around the world. Effectiveness of hormonal contraceptives may be related to metabolic changes in obesity or greater body mass or body fat. Hormonal contraceptives mainly include oral contraceptives, injectables and implants, the transdermal patch, and the vaginal ring. We systematically reviewed the evidence on the effectiveness of hormonal contraceptives among overweight and obese women.

OBJECTIVES

To examine the effectiveness of hormonal contraceptives in preventing unplanned pregnancies among women who are overweight or obese versus women of lower weight or body mass index (BMI).

SEARCH METHODS

Through January 2013, we searched MEDLINE, CENTRAL, POPLINE, ClinicalTrials.gov, and ICTRP. The previous search also included EMBASE. We contacted investigators to identify other trials.

SELECTION CRITERIA

All study designs were eligible. Any type of hormonal contraceptive could have been examined. Reports had to contain information on the specific contraceptive method(s). The primary outcome was pregnancy. Overweight or obese women must have been identified by an analysis cutoff for weight or BMI (kg/m(2)).

DATA COLLECTION AND ANALYSIS

Data were abstracted by two authors. Life-table rates were included where available. For dichotomous variables, we computed an odds ratio with 95% confidence interval (CI). We used reported pregnancy rates or relative risk (RR) when those were the only results provided. The main comparisons were between overweight or obese women and women of lower weight or BMI. We assessed the quality of evidence for this review.

MAIN RESULTS

We found nine reports with data from 13 trials that included a total of 49,712 women. Five reports from 2002 to 2012 compared BMI groups; of those, one reported a higher pregnancy risk for overweight or obese women. In that trial, women assigned to an oral contraceptive containing norethindrone acetate 1.0 mg plus EE 20 µg and having a BMI at least 25 had greater pregnancy risk compared to those with BMI less than 25 (reported RR 2.49; 95% CI 1.01 to 6.13). The comparisons reported in the other four studies were not significantly different for pregnancy. These included studies of a combined oral contraceptive (COC), a transdermal patch, an implant, and an injectable. The COC study showed no trend by BMI or weight. With the transdermal patch, body weight was associated with pregnancy (reported P < 0.001) but BMI was not. The implant study had one pregnancy and the injectable study reported no pregnancies.Four studies from the 1990s used weight alone rather than BMI. Results were mixed. Studies of a vaginal ring (never marketed) and a six-rod implant showed higher pregnancy rates for women weighing at least 70 kg versus those weighing less than 70 kg (reported P values: 0.0013 and < 0.05, respectively). However, two implant studies showed no trend by body weight.

AUTHORS' CONCLUSIONS

The evidence did not generally show an association of BMI with effectiveness of hormonal contraceptives. However, the evidence was limited for any individual contraceptive method. Studies using BMI (rather than weight alone) can provide more information about whether body composition is related to contraceptive effectiveness. The efficacy of subdermal implants and injectable contraceptives may be unaffected by body mass. The contraceptive methods examined here are among the most effective when the recommended regimen is followed.The overall quality of evidence was low for this review. More recent reports provided moderate quality evidence, while the older studies provided evidence of low or very low quality for our purposes. Investigators should consider adjusting for potential confounding related to BMI. Trials should be designed to include sufficient numbers of overweight or obese women to adequately examine effectiveness and side effects of hormonal contraceptives within those groups.

Current status of contraceptive vaginal rings

Contraceptive vaginal rings (CVR) offer a new, effective contraceptive option, expanding the available choices of hormonal contraception. Various ring prototypes have been evaluated: progestin-only rings and combined progestin-estrogen rings, as well as different combination of progestins and estrogens. The progestin-only ring is intended for continuous use, whereas the combined ring has been designed for cyclic 3-week in/1-week out use, although several studies have explored alternative schemes of extended use. However, only two ring designs have reached the market: NuvaRing, a 1-month combined ring that releases etonogestrel and ethinylestradiol, and Progering, a 3-month progesterone-releasing ring for use in lactating women. A one year Nestorone/ethinyl estradiol CVR is approaching the final stages of development, as the Population Council is preparing to submit a new drug application to the Food and Drug Administration. The main advantages of CVRs are their effectiveness (similar or slightly better than the pill), ease of use without the need of remembering a daily routine, user ability to control initiation and discontinuation, nearly constant release rate allowing for lower doses, greater bioavailability and good cycle control with the combined ring, in comparison with oral contraceptives. Current prototypes in development include rings releasing progesterone receptor modulators, which would provide estrogen-free contraception, as well as combined rings releasing estradiol, instead of ethinyl-estradiol, providing a safer profile. Furthermore, intensive efforts towards developing dual protection rings, providing both contraception and protection against reproductive tract infections, offer hope that this greatly needed technology will soon undergo clinical testing and will be in the hands of women worldwide in the near future.

Hormonal contraceptives for contraception in overweight or obese women

BACKGROUND

Obesity has reached epidemic proportions around the world. Metabolic changes in obesity and greater body mass may lead to reduced effectiveness of hormonal contraceptives, such as the skin patch, vaginal ring, implants, and injectables. We systematically reviewed the evidence on the effectiveness of hormonal contraceptives among overweight and obese women.

OBJECTIVES

To examine the effectiveness of hormonal contraceptives in preventing unplanned pregnancies among women who are overweight or obese versus women of lower weight or body mass index (BMI).

SEARCH STRATEGY

We searched MEDLINE, CENTRAL, POPLINE, EMBASE, ClinicalTrials.gov, and ICTRP. We also contacted investigators to identify other trials.

SELECTION CRITERIA

All study designs were eligible. Any type of hormonal contraceptive could have been examined. The primary outcome was pregnancy. Overweight or obese women must have been identified by an analysis cutoff for weight or BMI (kg/m(2)).

DATA COLLECTION AND ANALYSIS

Data were abstracted by two authors; life-table rates were included where available. For dichotomous variables, we computed an odds ratio with 95% confidence interval. The main comparisons were between overweight or obese women and women of lower weight or BMI.

MAIN RESULTS

We found 7 reports with data from 11 trials that included 39,531 women. One of three studies using BMI found a higher pregnancy risk for overweight or obese women. In the trial of two combination oral contraceptives, women with BMI >= 25 had greater pregnancy risk compared to those with BMI < 25 (OR 1.91; 95% CI 1.01 to 3.61). Among skin patch users, body weight was associated with pregnancy (reported P < 0.001) but BMI was not. Studies of a vaginal ring (never marketed) and a six-rod implant showed higher pregnancy rates for women weighing >= 70 kg versus those weighing < 70 kg (reported P values: 0.0013 and < 0.05, respectively). However, two implant studies showed no trend by body weight, and trials of an injectable had no pregnancies.

AUTHORS' CONCLUSIONS

Body weight addresses overall body size, while BMI generally reflects the amount of fat. Only one of three studies using BMI found a higher pregnancy risk for overweight women. The efficacy of implants and injectable contraceptives may be unaffected by body mass. The field could use trials of contraceptive methods with groups stratified by BMI. The current evidence on effectiveness by BMI is limited. However, the contraceptive methods examined here are still among the most effective when the recommended regimen is followed.

A Comparison Between the Vaginal Ring and Oral Contraceptives

OBJECTIVE

To investigate whether contraceptive vaginal ring use results in similar estimated genital symptoms, signs, examination, and laboratory findings compared with oral contraceptive use.

METHODS

Women were randomly assigned to either contraceptive vaginal ring or a 20 microg ethinyl estradiol oral contraceptive pill use for 3 consecutive 28-day cycles, directly followed by 3 cycles of the study drug not initially assigned. Subjects scored genital symptoms on a daily diary using a 0-4 scale and underwent a baseline, cycle 2, cycle 4, and exit pelvic examination including vaginal discharge evaluation, vaginal Gram stain and white cell count, and culture for yeast and Lactobacillus, including colony count and hydrogen peroxide production.

RESULTS

Of the 40 subjects assigned to each arm, 33 (82.5%) subjects in the ring-first arm and 31 (77.5%) subjects in the pill-first arm completed all study visits (P =.58). Most subjects reported few genital symptoms with either method, but 63% of subjects reported vaginal wetness during ring use compared with 43% during pill use. During ring use larger numbers of Lactobacillus colonies present were positive for hydrogen peroxide production (fold difference 2.67, 95% confidence interval 1.49, 4.78, P <.001). All other laboratory data, including yeast colony counts, Nugent Gram stain score, vaginal white blood cell count, vaginal pH, and discharge weight, were not significantly different by method.

CONCLUSION

Some women may notice an increase in vaginal wetness during contraceptive ring use yet the method is well tolerated and appears to improve the vaginal flora.

Why consider vaginal drug administration?

OBJECTIVE

To review the anatomy and physiology of the vagina, the merits of vaginal drug administration, and the currently available vaginal drug-administration systems.

DESIGN

Review of basic and clinical research.

RESULT(S)

Although clinicians commonly use topically administered drugs in the vagina, this route for systemic drug administration is somewhat novel. Experience with a variety of products demonstrates that the vagina is a highly effective site for drug delivery, particularly in women's health. The vagina is often an ideal route for drug administration because it allows for the administration of lower doses, steady drug levels, and less frequent administration than the oral route. With vaginal drug administration, absorption is unaffected by gastrointestinal disturbances, there is no first-pass effect, and use is discreet. Knowledge of anatomy, physiology, histology, and immunology of the vagina should allow clinicians to reassure their patients concerning this mode of delivery. Greater understanding and experience by clinicians should lead to increased use and acceptance of the vagina as a route for drug administration.

CONCLUSION(S)

The safety and efficacy of vaginal administration have been well established. The vaginal route of drug delivery is acceptable and may even be a preferable route of administration for many drugs, particularly hormones, whether for contraception or postmenopausal estrogen therapy.

New delivery systems in contraception: vaginal rings

Vaginal rings, made of soft flexible silicone rubber, for delivery of contraceptive hormones are currently gaining clinical acceptance. This method provides extended release of hormones, which are implanted in the core of the ring and slowly disseminate into vaginal tissue. Although formulations and sizes vary, most rings are approximately 58 mm in diameter with a cross-section of 8.4 mm. Depending on the type of ring used, prolonged hormone release may occur from 3 weeks to 1 year. Advantages of the vaginal ring method are that it is user controlled, does not interfere with intercourse, does not require daily intake of a pill, and allows continuous delivery of a low dose of steroids. The Population Council has developed a progesterone-releasing ring, which is currently on the market in Chile and Peru for contraception in breastfeeding women. This ring may be effective for progesterone therapy during in vitro fertilization as well. A contraceptive ring releasing very low doses of the potent progestin Nestorone (Population Council, New York, NY) for 6 to 12 months is also under investigation. The optimal ring formulations, however, contain hormone combinations that provide excellent contraceptive efficacy with few side effects and good control of menstrual bleeding. The Food and Drug Administration has recently approved Organon's monthly ring releasing etonogestrel and ethinyl estradiol. The Population Council is developing a 1-year contraceptive ring releasing low doses of Nestorone and ethinyl estradiol. Combination rings are associated with very low pregnancy rates and side effects consistent with those of oral contraceptives.

Comparison of cycle control with a combined contraceptive vaginal ring and oral levonorgestrel/ethinyl estradiol

OBJECTIVE

The purpose of this study was to compare cycle control and tolerability of the NuvaRing (NV Organon, Oss, The Netherlands), a novel combined contraceptive vaginal ring, with a standard combined oral contraceptive pill.

STUDY DESIGN

Healthy women aged 18 to 40 years who requested contraception received either NuvaRing or a combined oral contraceptive containing 30 microg ethinyl estradiol and 150 microg levonorgestrel for 6 cycles in 3 similarly designed studies. Each cycle comprised 3 weeks of ring or pill use, followed by 1 ring- or pill-free week.

RESULTS

Two hundred forty-seven women began the studies, 121 women with NuvaRing and 126 women with the combined oral contraceptive. Withdrawal bleeding occurred in virtually all cycles in both groups. In the NuvaRing groups, the incidence of irregular bleeding was < or =5% in all cycles; this was lower than the combined oral contraceptive groups (5.4%-38.8%). Furthermore, the incidence of a normal intended bleeding pattern was significantly higher in the NuvaRing groups than in the combined oral contraceptive groups (P <.01). Both contraceptives were well tolerated.

CONCLUSION

NuvaRing has excellent cycle control and is well tolerated.

Ovarian function during use of vaginal rings delivering three different doses of Nestorone

Contraceptive vaginal rings delivering various progestins alone or in combination with estrogen have been previously studied, showing adequate steroid vaginal absorption and acceptability by the users. Nestorone progestin (NES) is a potent 19-nor-progesterone derivative, inactive by the oral route, but an excellent option for vaginal delivery. The purpose of this study was to evaluate ovarian function during 6 months of continuous use of progestin-only vaginal rings delivering 3 different doses of NES: 50, 75, and 100 microg per day. Blood samples were taken twice a week for 5 consecutive weeks during a control cycle and on months 1, 3 and 6 of use, for the measurement of estradiol (E2), progesterone (P), and NES. A total of 87 volunteers randomly received each of the 3 doses. After an initial peak, NES serum levels remained fairly constant throughout the duration of the study at about 125, 200 and 250 pmol/L, respectively, decreasing slightly with time. Luteal activity occurred very rarely (1.2-2.6% of sampling periods) with no apparent difference between doses. Low E2 levels (< or =100 pmol/L) in all samples of a run were rare (5%) and only with the high dose ring (100 microg/day). E2 remained within normal levels (101-1500 pmol/L) in most of the segments studied. We conclude that the 50 and 75 microg/day NES rings provide adequate ovulation inhibition without hypoestrogenism, while the 100 microg/day ring may deliver an unnecessarily high dose.

Efficacy, tolerability and acceptability of a novel contraceptive vaginal ring releasing etonogestrel and ethinyl oestradiol

A novel contraceptive vaginal ring releasing etonogestrel 120 microg and ethinyl oestradiol 15 microg daily over a period of 3 weeks was tested. Each ring was used for one cycle, comprising 3 weeks of ring use followed by a 1 week ring-free period. This 1 year, multicentre study assessed the contraceptive efficacy, cycle control, tolerability and acceptability of the contraceptive. Altogether, 1145 women were exposed to the vaginal ring for 12,109 cycles (928 woman-years). Six pregnancies occurred during treatment, giving a Pearl Index of 0.65 (95% confidence interval 0.24--1.41). Cycle control was very good, since irregular bleeding was rare (2.6--6.4% of evaluable cycles) and withdrawal bleeding (mean duration 4.7--5.3 days) occurred in 97.9--99.4% of evaluable cycles. Compliance to the prescribed regimen was high with criteria being fulfilled in 90.8% of cycles. The ring was well tolerated. The majority of women considered this new contraceptive method easy to use, and it offers an effective, convenient, well-accepted and novel method for hormonal contraception.

New contraceptive methods

As the number of abortion procedures performed each year reaches nearly 1 million, the incentive to decrease the incidence of unwanted pregnancy in the United States is high. Better education regarding women's health issues and enhanced contraceptive development are necessary to impact this long-standing problem. Several new contraceptive products are likely to become available in years to come to increase the number of choices that women and their health care providers have for pregnancy prevention. These products include long-acting implants, the levonorgestrel intrauterine device, patches, and the vaginal ring. This article surveys the near future of male and female contraception.

A comparative study of two contraceptive vaginal rings releasing norethindrone acetate and differing doses of ethinyl estradiol

Two combined contraceptive vaginal rings (CVR) each releasing approximately 1 mg norethindrone acetate (NET-Ac) and either 20 micrograms or 15 micrograms ethinyl estradiol over 24 h were tested at three clinic sites in Los Angeles, San Francisco, and Sydney. A total of 61 women were enrolled to use the ring on a schedule of 3 weeks in/1 week out for four treatment cycles. Serum estradiol, progesterone, norethindrone (NET), and ethinyl estradiol (EE) levels were assayed twice weekly in all four treatment cycles. Both CVR performed well, with no pregnancies occurring and only one cycle of luteal activity suggestive of ovulation (serum progesterone > 32 nmol/L) occurring with each ring (0.9% of cycles with the 1/15 ring and 1.2% of cycles with the 1/20 ring). Although there was significantly more luteal activity in women using the 1/15 CVR (5.9% compared with 1.2% of cycles), only three cycles with a marked degree of luteal activity (progesterone > 10 nmol/L) occurred among compliant women. Serum levels of NET and EE were consistently elevated during use of both rings. There was no significant difference between serum levels with the two rings because of wide interindividual variations, although both NET and EE levels tended to be higher with the 1/20 ring. However, there was a significant difference in EE levels between the women in Los Angeles and Sydney using the same dose rings. Total cholesterol, HDL, and LDL cholesterol values were not significantly changed during treatment. Triglycerides increased but remained within the normal range. Overall cycle control was good with both formulations, but there was slightly more cycle disturbance with the lower dose ring. There was no change in mean body weight during the study, and individual weight changes appeared to be idiosyncratic. Side effects were infrequent and similar to those reported with other steroidal contraceptive methods. Three women complained of vaginal discharge, one with accompanying itch and one with a vaginal Candida infection in cycle 1. Overall, both of these EE/NET-Ac rings performed well, with only minor and mainly nonsignificant differences in effect on serum EE, NET, E2, and progesterone levels and lipids, and on vaginal bleeding patterns.