The contraceptive vaginal ring (NuvaRing®) and hemostasis: a comparative study

U.S. Medical Eligibility Criteria for Contraceptive Use, 2024

The 2024 U.S. Medical Eligibility Criteria for Contraceptive Use (U.S. MEC) comprises recommendations for the use of specific contraceptive methods by persons who have certain characteristics or medical conditions. These recommendations for health care providers were updated by CDC after review of the scientific evidence and a meeting with national experts in Atlanta, Georgia, during January 25-27, 2023. The information in this report replaces the 2016 U.S. MEC (CDC. U.S. Medical Eligibility Criteria for Contraceptive Use, 2016. MMWR 2016:65[No. RR-3]:1-103). Notable updates include 1) the addition of recommendations for persons with chronic kidney disease; 2) revisions to the recommendations for persons with certain characteristics or medical conditions (i.e., breastfeeding, postpartum, postabortion, obesity, surgery, deep venous thrombosis or pulmonary embolism with or without anticoagulant therapy, thrombophilia, superficial venous thrombosis, valvular heart disease, peripartum cardiomyopathy, systemic lupus erythematosus, high risk for HIV infection, cirrhosis, liver tumor, sickle cell disease, solid organ transplantation, and drug interactions with antiretrovirals used for prevention or treatment of HIV infection); and 3) inclusion of new contraceptive methods, including new doses or formulations of combined oral contraceptives, contraceptive patches, vaginal rings, progestin-only pills, levonorgestrel intrauterine devices, and vaginal pH modulator. The recommendations in this report are intended to serve as a source of evidence-based clinical practice guidance for health care providers. The goals of these recommendations are to remove unnecessary medical barriers to accessing and using contraception and to support the provision of person-centered contraceptive counseling and services in a noncoercive manner. Health care providers should always consider the individual clinical circumstances of each person seeking contraceptive services. This report is not intended to be a substitute for professional medical advice for individual patients; when needed, patients should seek advice from their health care providers about contraceptive use.

Analysis and new contraception frontiers with combined vaginal rings

Combined vaginal rings (ethinylestradiol (EE)/desogestrel), indicated for contraception, are highly effective, comparable to other combined hormonal contraceptives, such as pills. In addition to this benefit, vaginal rings are easy to use, with a probable lower risk of forgetting, due to their non-daily, monthly schedule. Besides, for users with poor gastric tolerance to oral formulations, they represent a method with safety and comparable extraconceptive benefits. The latest generation rings have a novel polymeric structure, do not need special storage methods and do not generate accelerated initial release of EE, reducing the early increased systemic exposure to the synthetic steroids they contain. This review describes main aspects related to its use, efficacy, and safety for contraceptive purposes.

No. 329-Canadian Contraception Consensus Part 4 of 4 Chapter 9: Combined Hormonal Contraception

OBJECTIVE

To provide guidelines for health care providers on the use of contraceptive methods to prevent pregnancy and on the promotion of healthy sexuality.

OUTCOMES

Overall efficacy of cited contraceptive methods, assessing reduction in pregnancy rate, safety, and side effects; the effect of cited contraceptive methods on sexual health and general well-being; and the availability of cited contraceptive methods in Canada.

EVIDENCE

Medline and the Cochrane Database were searched for articles in English on subjects related to contraception, sexuality, and sexual health from January 1994 to December 2015 in order to update the Canadian Contraception Consensus published February-April 2004. Relevant Canadian government publications and position papers from appropriate health and family planning organizations were also reviewed.

VALUES

The quality of the evidence is rated using the criteria described in the Report of the Canadian Task Force on Preventive Health Care. Recommendations for practice are ranked according to the method described in this report.

SUMMARY STATEMENTS

RECOMMENDATIONS.

A Review of Hormonal Contraception and Venous Thromboembolism in Adolescents

BACKGROUND

The number of adolescents who are prescribed hormonal contraception (HC) for contraceptive and noncontraceptive indications is increasing. Approximately 1 of 4 female adolescents will use some form of HC by age 19 years. Venous thromboembolism (VTE) is a rare, but life-threatening complication associated with HC use. Although adolescents aged 15 to 19 years have the lowest absolute HC-associated VTE risk, they still account for 5.9% of HC-associated VTE. The absolute HC-associated VTE risk for those younger than 15 years of age is not well described.

OBJECTIVE

The objectives of this report are to describe the current literature regarding HC-associated VTE in adolescents, to review the coagulation cascade and in vivo coagulation, to highlight differences between the adolescent and adult coagulation profiles, to discuss coagulation profile changes related to HC use, and to identify knowledge deficits for future study.

CONCLUSION

The mechanisms and confounding variables that lead to HC-associated VTE in all adolescents are not well understood because many large HC studies exclude female adolescents younger than 18 years of age. Because of the paucity of data in this age group, observational studies and randomized controlled trials of VTE risk in adolescents on varying forms of HC are needed. Studies should include female adolescents across the entire adolescent age span (12-21 years) to better understand HC-associated VTE risk in this population.

Sexual Desire and Hormonal Contraception

OBJECTIVE

To examine the effect of hormonal contraception on sexual desire.

MATERIALS AND METHODS

We performed a cross-sectional analysis of 1,938 of the 9,256 participants enrolled in the Contraceptive CHOICE Project. This subset included participants enrolled between April and September 2011 who completed a baseline and 6-month telephone survey. Multivariable logistic regression was used to assess the association between contraceptive method and report of lacking interest in sex controlling for potential confounding variables.

RESULTS

More than 1 in 5 participants (23.9%) reported lacking interest in sex at 6 months after initiating a new contraceptive method. Of 262 copper intrauterine device (IUD) users (referent group), 18.3% reported lacking interest in sex. Our primary outcome was more prevalent in women who were young (younger than 18 years: adjusted odds ratio [OR] 2.04), black (adjusted OR 1.78), and married or living with a partner (adjusted OR 1.82). Compared with copper IUD users, participants using depot medroxyprogesterone (adjusted OR 2.61, 95% confidence interval [CI] 1.47-4.61), the vaginal ring (adjusted OR 2.53, 95% CI 1.37-4.69), and the implant (adjusted OR 1.60, 95% CI 1.03-2.49) more commonly reported lack of interest in sex. We found no association between use of the hormonal IUD, oral contraceptive pill, and patch and lack of interest in sex.

CONCLUSION

CHOICE participants using depot medroxyprogesterone acetate, the contraceptive ring, and implant were more likely to report a lack of interest in sex compared with copper IUD users. Future research should confirm these findings and their possible physiologic basis. Clinicians should be reassured that most women do not experience a reduced sex drive with the use of most contraceptive methods.

Intravaginal rings as delivery systems for microbicides and multipurpose prevention technologies

There is a renewed interest in delivering pharmaceutical products via intravaginal rings (IVRs). IVRs are flexible torus-shaped drug delivery systems that can be easily inserted and removed by the woman and that provide both sustained and controlled drug release, lasting for several weeks to several months. In terms of women's health care products, it has been established that IVRs effectively deliver contraceptive steroids and steroids for the treatment of postmenopausal vaginal atrophy. A novel application for IVRs is the delivery of antiretroviral drugs for the prevention of human immunodeficiency virus (HIV) genital infection. Microbicides are antiviral drugs delivered topically for HIV prevention. Recent reviews of microbicide IVRs have focused on technologies in development and optimizing ring design. IVRs have several advantages, including the ability to deliver sustained drug doses for long periods of time while bypassing first pass metabolism in the gut. IVRs are discreet, woman-controlled, and do not require a trained provider for placement or fitting. Previous data support that women and their male sexual partners find IVRs highly acceptable. Multipurpose prevention technology (MPT) products provide protection against unintended/mistimed pregnancy and reproductive tract infections, including HIV. Several MPT IVRs are currently in development. Early clinical testing of new microbicide and MPT IVRs will require a focus on safety, pharmacokinetics and pharmacodynamics. Specifically, IVRs will have to deliver tissue concentrations of drugs that are pharmacodynamically active, do not cause mucosal alterations or inflammation, and do not change the resident microbiota. The emergence of resistance to antiretrovirals will need to be investigated. IVRs should not disrupt intercourse or have high rates of expulsion. Herein, we reviewed the microbicide and MPT IVRs currently in development, with a focus on the clinical aspects of IVR assessment and the challenges facing microbicide and MPT IVR product development, clinical testing, and implementation. The information in this review was drawn from PubMed searches and a recent microbicide/MPT product development workshop organized by CONRAD.

The combined contraceptive vaginal ring (NuvaRing): evaluation of the clinical and pharmacological evidence

The NuvaRing((R)) is a vaginal ring contraceptive that releases a daily dose of 15 microg ethinylestradiol and 120 microg etonogestrel through the vaginal epithelium, thereby avoiding the daily fluctuations in serum levels typically observed with combined oral contraceptives. Each ring is designed for a single 3-week use followed by a 1-week ring-free period. The ring offers robust inhibition of ovulation, yielding a Pearl Index of 0.65 for European women in registration trials. The ring has the same contraindications as combined oral contraceptives. The vaginal ring is a highly effective, safe and well-tolerated method of hormonal contraception designed for reproductive-aged women who desire freedom from the daily pill.

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.

Oral versus vaginal combined hormonal contraceptives' effect on coagulation and inflammatory biomarkers among young adult women

In order to compare the effect of combined oral contraceptive (COC) and combined vaginal contraceptive (CVC) methods on the inflammation and procoagulation, we recruited female participants in 3 groups: control participants, COC users, and CVC users. We measured different blood biomarkers. The users of both COC and CVC had higher levels of C-reactive protein (P < .0001) and factor VII (P < .0001). However, CD40 ligand was only higher for COC users (P < .0001) and not the CVC users. Even though the levels of thrombin/antithrombin III were not higher for COC and CVC users, as compared to the controls, CVC users had higher levels as compared to COC users (P = .0327). As compared to the control group, we observed higher levels von Willebrand factor among CVC users but not the COC users. Longitudinal studies with larger sample size are needed to better assess the inflammatory and procoagulation response due to CVC use.

Evaluation of the Coagulation Profile Among Oral and Vaginal Combined Hormonal Contraceptive Users Using Sonoclot Coagulation Analyzer

Combined hormonal contraceptives possess an inherent risk of thrombus-related events. The purpose of this study is to elucidate alterations in the coagulation profile among young women using combined oral contraceptive (COC) or combined vaginal contraceptive (CVC) compared to a normal, healthy, female control group using the Sonoclot coagulation analyzer. We enrolled 159 participants (64 control individuals, 51 COC users, and 44 CVC users). Each participant completed a survey of medical history, family medical history, and lifestyle choices. Citrated venous whole blood was collected and analyzed using the Sonoclot coagulation analyzer. After adjusting for age, race, alcohol consumption, sleeping habits, and family history of cardiovascular disease, and stroke, we observed COC and CVC users had mostly similar coagulation profiles except when compared to the control, and COC and CVC users had an elevated glass bead peak signal while COC users had a shorter peak time.

Cerebrovascular Events and Use of NuvaRing

Objective:

To report 2 cases, occurring within 1 month at a single institution, in which young women experienced a cerebrovascular event while using the hormonal contraceptive product NuvaRing (etonogestrel/ethinyl estradiol vaginal ring).

Case Summary:

The first patient presented to the emergency department (ED) with a 10-day history of right frontal headache. A computed tomography (CT) scan and magnetic resonance imaging showed evidence for right postcentral and cortical venous thrombosis. A hypercoagulable workup identified a heterozygous factor V Leiden mutation. The second patient presented to the ED with a same-day history of left frontotemporal headache extending into her left jaw and neck, numbness and clumsiness of right hand and right foot, and inability to make a comprehensible sentence. A CT angiogram showed occlusion of the internal and external carotid arteries. A hypercoagulable workup indicated no evidence of a thrombophilic disorder and a transesophageal echocardiogram indicated no cardioembolic source, resulting in a final diagnosis of a spontaneous carotid artery dissection. Both patients reported recent use of NuvaRing. The medication was discontinued during the hospital stay.

Discussion:

The use of hormonal agents for contraception carries a well-known risk of venous thrombosis; however, the impact this therapy has on the risk of arterial thrombosis and ischemic brain events is less understood. We found no previous reports of an ischemic brain event in association with NuvaRing use. The Naranjo probability scale indicated a possible relationship between the ischemic events and NuvaRing exposure in both patients.

Conclusions:

Risk factors should be evaluated appropriately prior to initiating any form of combined hormonal contraceptives, oral or vaginal, in young women.

Review of the combined contraceptive vaginal ring, NuvaRing

The purpose of this review was to test contraceptive efficacy, cycle control, tolerability, and acceptability as found in the non-comparative studies with NuvaRing^® by those found in the randomized trials comparing NuvaRing and combined oral contraceptives (COCs). All large non-comparative studies and all relevant randomized controlled trials (RCTs) between NuvaRing and a COC up to and including December 2006 were analyzed. Two large multi-center registration studies, 1 large daily clinical practice study, and 6 RCTs comparing NuvaRing and a COC were identified. The findings in the non-comparative studies were confirmed in the RCTs. Contraceptive efficacy was high showing no significant differences in comparison with the COC; cycle control was good and consistently better than that of the COC; compliance was high and comparable with that of the pill; the incidence of adverse events such as breast tenderness, headache, and nausea was low, but not lower than with the COC despite a halving of the systemic exposure to ethinyl estradiol (EE) with NuvaRing compared with a 30-μg EE-containing COC; the incidence of local and ring-related events was low but higher than with the COC, leading to higher discontinuation rates among NuvaRing users; acceptability was high and comparable between both contraceptives, resulting in a global improvement of sexual function with both methods. After study completion, women using NuvaRing were more likely to continue with their method than women using a COC. The good results with respect to contraceptive efficacy, cycle control, tolerability, and acceptability as achieved with NuvaRing in the large non-comparative registration studies were confirmed in the RCTs comparing NuvaRing with different COCs.

Metabolic effects of contraceptive steroids

Estrogen and progestins have been used by millions of women as effective combined contraceptives. The safety of hormonal contraceptives has been documented by years of follow-up and serious adverse events that may be related to their use are rare in the young population exposed to these agents. The balance between the benefits and the risks of contraceptive steroids is generally positive in particular when comparing to the risks of pregnancy and especially in women with risk factors. The metabolic changes induced by the synthetic steroids used in contraception, such as lipoprotein changes, insulin response to glucose, and coagulation factors have been considered as potential markers of cardiovascular and venous risk. Observations of these effects have led to modifications of the composition of hormonal contraceptive in order to minimize these changes and hence potentially decrease the risks. The synthetic estrogen Ethinyl-Estradiol (EE) exerts a stronger effect that natural estradiol (E2) on hepatic metabolism including estrogen-dependent markers such as liver proteins. This stronger hepatic impact of EE has been related to its 17α-ethinyl group which prevents the inactivation of the molecule and results in a more pronounced hepatic effect of EE as compared to estradiol. Due to its strong activity, administering EE via a non-oral route does not prevent its impact on liver proteins. In order to circumvent the metabolic changes induced by EE, newer products using more natural compounds such as estradiol (E2) and estradiol valerate (E2V) have been introduced. The synthetic progestins used for contraception are structurally related either to testosterone (T) (estranes and gonanes) or to progesterone (pregnanes and 19-norpregnanes). Several new progestins have been designed to bind more specifically to the progesterone receptor and to minimize side-effects related to androgenic, estrogenic or glucocorticoid receptor interactions. Dienogest (DNG), and drospirenone (DRSP) and the 19-norpregnanes including Nestorone® (NES), nomegestrol acetate (NOMAc) and trimegestone (TMG) have been combined with estrogen either EE or E2 or estradiol valerate (E2V). Risks and benefits of the newer progestins used in contraception depend upon the type of molecular structure, the type and dose of estrogen associated in a combination and the route of administration. The lower metabolic impact of estradiol-based combinations may result in an improved safety profile, but large surveillance studies are warranted to confirm this plausible hypothesis. So far, the contraindications and warnings for use of current COCs also apply to the estradiol-based COCs.

Examining the efficacy, safety, and patient acceptability of the combined contraceptive vaginal ring (NuvaRing)

The contraceptive vaginal ring is a novel contraceptive method that offers unique advantages. Intravaginal delivery of both estrogen and progesterone allows continuous release of medication, resulting in lower systemic levels. The use of long-term combined hormonal contraception enables improved cycle control compared with progesterone-only methods. The indications and usage of the NuvaRing^® are described along with the efficacy, tolerability, and safety. Overall, the contraceptive vaginal ring appears to be very effective, with a favorable side-effect profile, and is highly acceptable to most patients.

Plantar Vein Thrombosis due to Busy Night Duty on Intensive Care Unit

A 32-year-old woman with severe foot pain came to our emergency department after a busy night duty in hospital followed by an extended sleep period. Physical examination revealed a discrete swelling of the medial aspect of the right foot and a painful plantar arch during digital examination. Magnetic resonance imaging (MRI) with intravenous gadolinium showed filling defects in the lateral plantar vein. Doppler sonography displayed noncompressible structures in the plantar veins without flow signals, suggesting a plantar vein thrombosis. Therapy was initiated with low-molecular-weight heparin in combination with customized elastic bandages for the lower leg. Follow-up sonography 6 weeks later showed complete patency of the plantar veins. To our knowledge, we present the first case of isolated plantar vein thrombosis independent of trauma, surgery, or malignant disease, most probably caused by a busy night duty on the intensive care unit (ICU) followed by a prolonged sleeping period.

Use of the NuvaRing hormone-releasing system in late reproductive-age women with type 1 diabetes mellitus

AIM

To evaluate the effect of the vaginally inserted hormone-releasing system NuvaRing on carbohydrate and lipid metabolism and the hemostasis system, over 6 months of use, in late reproductive-age women with type 1 diabetes mellitus (DM).

METHODS

The open randomized study included a total of 25 women with type 1 DM using NuvaRing. Average daily insulin requirements, levels of glycosylated hemoglobin (HbA1c), total cholesterol, triglycerides, low-density lipoprotein cholesterol and high-density lipoprotein cholesterol, the state of coagulation hemostatis and fibrinolytic activity were determined at baseline and after 3 and 6 months of contraception. The control group was composed of 20 age-matched women with type 1 DM using no methods of contraception, as well as 20 apparently healthy women using the NuvaRing device.

RESULTS

Use of the NuvaRing contraceptive system in type 1 DM women in the late reproductive period was shown to exert no clinically significant effect on carbohydrate and lipid metabolism on the background of persistent and satisfactory compensation of carbohydrate metabolism (HbA1c < or = 7.5%), with a neutral impact on the hemostasis system.

CONCLUSION

The NuvaRing hormone-releasing system proved to be a reliable and safe means of contraception for late reproductive-age women with type 1 DM.

Intravaginal oestrogen and progestin administration: advantages and disadvantages

The vagina provides a local and a systemic route for delivering hormones for systemic effects and uterine targeting. Due to the 'uterine first-pass effect', hormones concentrate in the uterus and nearby tissues with low systemic exposure. Vaginal oestrogens, progesterone/progestins and danazol are currently used to obtain local (vagina and urethra), regional (uterus, pelvic structures) and systemic effects or contraception. Very low dosages of transvaginal oestrogens in the forms of creams, tablets and rings are effective for vaginal atrophy and urinary incontinence. To avoid endometrial stimulation, no deep vaginal application of low dosages for less than 6 months is recommended. For postmenopausal hormonal therapy by the vaginal route, progesterone is delivered directly to the uterus; the target organ for which it is designed. Worldwide, vaginal progesterone is employed for luteal phase support. Contraceptive vaginal rings offer the advantages of non-oral administration and sustained release. Vaginal administration of steroids is a promising option for the treatment of endometriosis.

The combined etonogestrel/ethinyl estradiol contraceptive vaginal ring

Many factors influence the effectiveness of contraceptive methods. Oral contraceptives are the second most popular contraceptive method after female sterilization in the US. A total of 25% of women do not use their oral contraceptives correctly; 30% of women do not use them consistently. Several new contraceptive methods with alternate routes of delivery and less frequent dosing are available. The combined etonogestrel/ethinyl estradiol contraceptive vaginal ring is marketed under the name of NuvaRing. This is the only contraceptive ring approved by the FDA. The administration of steroids by the vaginal route may offer many advantages. Because of less frequent dosing, self-administration, and possibly, an improved side effect profile, the ring has the potential to increase successful use.

Effects of oral and transvaginal ethinyl estradiol on hemostatic factors and hepatic proteins in a randomized, crossover study

CONTEXT

The use of combined hormonal contraceptives with ethinyl estradiol (EE) and a progestin results in alterations in potential biomarkers of venous thromboembolism risk. Evaluation of the impact of delivery route on these changes is difficult due to an interaction between EE and the progestin component.

OBJECTIVE

The aim of the study was to compare the impact of oral and vaginal administration of EE alone on hemostatic variables and estrogen-sensitive liver proteins.

DESIGN

This was a single-center, randomized, crossover study with two treatment cycles separated by a washout cycle.

SETTING

The study was conducted in an academic outpatient center.

PARTICIPANTS

Fourteen healthy postmenopausal women were enrolled; 13 completed the study and were included in the analyses.

INTERVENTION

Participants were randomized to receive EE (15 microg/d) delivered by oral tablet or vaginal ring for 21 d in one of two treatment sequences.

MAIN OUTCOME MEASURES

Changes in plasma concentration or activity of 10 hemostatic variables and six estrogen-sensitive liver proteins between baseline and d 21 of treatment were the primary outcomes.

RESULTS

Prothrombin fragment 1 + 2 plasma level was unaffected by treatment or delivery route. Angiotensinogen (expressed as plasma level of angiotensin I) increased similarly with oral and vaginal delivery; mean (sd) increases were 2757 (1033) and 2864 (893) ng /ml, respectively (P = 0.0002). Alterations in other study variables, except total cholesterol, were similar with oral and vaginal administration.

CONCLUSION

Our results provide evidence that the customary effects of combined hormonal contraceptives on hemostatic variables and estrogen-sensitive liver proteins are largely related to EE and independent of delivery route during short-term treatment.

Medical eligibility criteria for new contraceptive methods: combined hormonal patch, combined hormonal vaginal ring and the etonogestrel implant

To review evidence on the combined hormonal patch, combined hormonal vaginal ring and the etonogestrel implant, with a focus on safety and effectiveness of use among women with special health conditions, we searched MEDLINE, Pre-MEDLINE and the Cochrane Library for reports published from 1980 through March 2005. Articles eligible for review included 11 on the hormonal patch, nine on the hormonal ring, and 11 on the etonogestrel implant. Limited evidence suggests patch efficacy is lower among women>90 kg. No evidence was identified for vaginal ring use among women with medical conditions. A single small study found that etonogestrel implants had no adverse effects on bone mineral density among women 18-40 years old. Limited evidence also suggests no adverse effects of the etonogestrel implant on lactation parameters or infant development among users enrolled 28 to 56 days postpartum and followed for 4 months.

New progestagens for contraceptive use

The progestins have different pharmacologic properties depending upon the parent molecule, usually testosterone or progesterone (P), from which they are derived. Very small structural changes in the parent molecule may induce considerable differences in the activity of the derivative. In hormonal contraceptives, progestins represent the major agent designed for suppressing ovulation and are used in combination with estrogen (E) usually ethinyl-estradiol (EE). The development of new generations of progestins with improved selectivity profiles has been a great challenge. Steroidal and nonsteroidal progesterone receptor (PR) agonists have been synthesized as well, although the latter are still in a very early stage of development. Several new progestins, have been synthesized in the last two decades. These include dienogest (DNG), drospirenone (DRSP), Nestorone (NES), nomegestrol acetate (NOMAc) and trimegestone (TMG). These new progestins have been designed to have no androgenic or estrogenic actions and to be closer in activity to the physiological hormone P. DRSP differs from the classic progestins as it is derived from spirolactone. It is essentially an antimineralocorticoid steroid with no androgenic effect but a partial antiandrogenic effect. The antiovulatory potency of the different progestins varies. TMG and NES are the most potent progestins synthesized to date, followed by two of the older progestins, keto-desogestrel (keto-DSG) and levonorgestrel (LNG). The new molecules TMG, DRSP and DNG also have antiandrogenic activity. Striking differences exist regarding the side effects among the progestins and the combination with EE leads to other reactions related to the E itself and whether the associated progestin counterbalances, more or less, the estrogenic action. The 19-norprogesterone molecules and the new molecules DRSP and DNG are not androgenic and, therefore, have no negative effect on the lipid profile. Given their pharmacological properties, it is likely that the new progestins may have neutral effects on metabolic or vascular risks. However, this hypothesis must be confirmed in large clinical trials.

Vaginal delivery of contraceptives

Although a steady increase in contraceptive use has been observed both in developed and less-developed countries, the large number of unplanned pregnancies may indicate that the contraceptive needs of a significant percentage of couples have so far not been met. Several new contraceptive products have reached the market during the last 2 years. Among these is a new contraceptive vaginal ring, which has become available for prescription. This new female method has been developed to expand the contraceptive choices available to couples. This review will address the specifics of the vaginal route for delivering contraceptive steroids and describe the various systems available or under evaluation.