Pharmacokinetics of the etonogestrel contraceptive implant in obese women

Long-acting reversible contraception with etonogestrel implants in female macaques (Macaca mulatta and Macaca fascicularis)

Introduction

Contraception is often required for management and population control purposes in group-housed and free-roaming non-human primates. Long-acting reversible contraceptives, including subdermal progestin-releasing implants, are preferred as they eliminate challenges associated with frequent administration. Etonogestrel (ENG)-releasing subdermal implants are reversible and long-acting for a minimum of 3 years, and are commercially available for human use as Implanon® or Nexplanon®.

Methods

A retrospective analysis was performed detailing the contraceptive effectiveness and reversibility of subdermal placement of one-fourth or one-third of an ENG implant (68 mg/implant) in 129 female rhesus macaques (Macaca mulatta) and 67 cynomolgus macaques (Macaca fascicularis) at the Biomedical Primate Research Centre (Rijswijk, Netherlands). Furthermore, single cross-sectional ENG serum concentrations were measured for 16 rhesus and 10 cynomolgus macaques, and hemoglobin and blood chemistry pre-ENG and at timepoints >0.5, >1.5, and > 2.5 years post-ENG insertion were evaluated for 24 rhesus macaques. Finally, data were obtained using trans-abdominal ultrasound regarding the influence of ENG on uterine volume and endometrial thickness in 14 rhesus and 11 cynomolgus macaques.

Results

As a contraceptive ENG was in 99.80% (CI 93.50-99.99) and 99.95% (CI 99.95-100) effective in rhesus and cynomolgus macaques, respectively. Prolonged ENG durations of implant use in 14 rhesus macaques (range 3.1-5.0 years) and eight cynomolgus macaques (range 3.2-4.0 years) resulted in no unintended pregnancies. A total of 17 female macaques were allowed to breed after ENG removal, and among them, 14 female macaques (82%) had an uneventful delivery. Serum ENG concentrations with a median ENG duration of 1.2 years (range 0.1-6.0 years) and 1.9 years (range 0.6-4.7 years) resulted in median concentrations of 112 pg./mL (range 0-305 pg./mL) and 310 pg./mL (range 183-382 pg./mL) for rhesus and cynomolgus macaques, respectively. ENG had no clinical effect on hemoglobin and blood chemistry parameters nor on the thickness of the endometrial lining or uterus volume.

Conclusion

This study indicates that both one-fourth and one-third of the ENG implants are effective, long-acting, reversible, and safe contraceptive to use in macaques.

Misreporting contraceptive use and the association of peak study progestin levels with weight and BMI among women randomized to the progestin-only injectable contraceptives DMPA-IM and NET-EN

Progestin-only injectable contraceptives, mainly depo-medroxyprogesterone acetate intramuscular (DMPA-IM), are the most widely used contraceptive methods in sub-Saharan Africa. Insufficient robust data on their relative side-effects and serum concentrations limit understanding of reported outcomes in contraception trials. The WHICH clinical trial randomized HIV-negative women to DMPA-IM (n = 262) or norethisterone enanthate (NET-EN) (n = 259) at two South African sites between 2018-2019. We measured serum concentrations of study and non-study progestins at initiation (D0) and peak serum levels, one week after the 24-week injection [25 weeks (25W)], (n = 435) and investigated associations between study progestin levels, and BMI and weight of participants. Peak median serum concentrations were 6.59 (IQR 4.80; 8.70) nM for medroxyprogesterone (MPA) (n = 161) and 13.6 (IQR 9.01; 19.0) nM for norethisterone (NET) (n = 155). MPA was the most commonly quantifiable non-study progestin at D0 in both arms (54%) and at 25W in the NET-EN arm (27%), followed by NET at D0 in both arms (29%) and at 25W in the DMPA-IM arm (19%). Levonorgestrel was quantifiable in both arms [D0 (6.9%); 25W (3.4%)], while other progestins were quantifiable in ≤ 14 participants. Significant negative time-varying associations were detected between MPA and NET concentrations and weight and BMI in both contraceptive arms and a significant increase was detected for peak serum progestin concentrations for normal weight versus obese women. Contraceptive-related reported outcomes are likely confounded by MPA, more so than NET, with reported DMPA-IM effects likely underestimated, at sites where DMPA-IM is widely used, due to misreporting of contraceptive use before and during trials, and 'tail' effects of DMPA-IM use more than six months before trial enrolment. Peak serum levels of MPA and NET are negatively associated with BMI and weight, suggesting another source of variability between trial outcomes and a potential increase in side-effects for normal weight versus overweight and obese women. Trail registration: The clinical trial was registered with the Pan African Clinical Trials Registry (PACTR 202009758229976).

An overview of contraception in women with obesity

The use of safe and effective contraception is essential for preventing unplanned pregnancy in women of all body sizes. When counseling women with obesity about contraception, it is important to consider the pharmacokinetic alterations of obesity on various modern contraceptive methods. However, evidence is reassuring that most contraceptive methods are safe and effective in women with obesity. Individual countries and the World Health Organization have published Medical Eligibility Criteria to guide contraceptive selection in women with medical issues including obesity. When choosing contraception, specific risks of the method relative to any underlying medical disorders must also be balanced against the risks of unintended pregnancy in this group.

Society of Family Planning Clinical Recommendation: Extended Use of Long Acting Reversible Contraception

In this clinical recommendation, we review the evidence supporting the use of the copper intrauterine device, levonorgestrel intrauterine devices and etonogestrel subdermal implant beyond the Food and Drug Administration approved duration of use for contraception (extended use). Clinicians should discuss effectiveness as well as other clinical considerations with patients to allow them to make contraceptive decisions that support their reproductive goals and clinical needs. Extended use of long acting reversible contraception may be a safe, effective and desirable option for many patients.

Non-oral routes, novel formulations and devices of contraceptives: An update

Family planning enables society to prevent unintended pregnancies and helps in attaining desired spacing between the pregnancies. It is done with the use of contraceptive methods and infertility treatments. The use of contraceptives serves to ease maternal ill-health and reduce pregnancy-related deaths and helps to decrease the number of unsafe abortions and HIV transmission from mothers to newborns. The most popular contraception method is a daily dose of combined oral contraceptives pills. However, poor compliance and various adverse effects are common problems of oral contraceptives that considerably reduce their long-term use. Thus, several non-oral contraceptive options have been developed for better compliance, reduced side effects and improved therapeutic efficacy. This review presented the non-oral contraceptive formulations given by different routes such as transdermal, nasal, subcutaneous, intramuscular, intrauterine and vaginal routes. These formulations delivering contraceptives, mainly through devices, include transdermal patches and microneedles, nasal sprays, intrauterine devices and intrauterine systems, vaginal rings, contraceptive implants and contraceptive injections, which are unique in their specific advantages and drawbacks.

Long-acting antiretrovirals: a new era for the management and prevention of HIV infection

The long-acting antiretroviral cabotegravir and rilpivirine combination has just received FDA, EMA and Health Canada approval. This novel drug delivery approach is about to revolutionize the therapy of people living with HIV, decreasing the 365 daily pill burden to only six intramuscular injections per year. In addition, islatravir, a first-in-class nucleoside reverse transcriptase translocation inhibitor, is intended to be formulated as an implant with a dosing interval of 1 year or more. At present, long-acting antiretroviral therapies (LA-ARTs) are given at fixed standard doses, irrespectively of the patient's weight and BMI, and without consideration for host genetic and non-genetic factors likely influencing their systemic disposition. Despite a few remaining challenges related to administration (e.g. pain, dedicated medical procedure), the development and implementation of LA-ARTs can overcome long-term adherence issues by improving patients' privacy and reducing social stigma associated with the daily oral intake of anti-HIV treatments. Yet, the current 'one-size-fits-all' approach does not account for the recognized significant inter-individual variability in LA-ART pharmacokinetics. Therapeutic drug monitoring (TDM), an important tool for precision medicine, may provide physicians with valuable information on actual drug exposure in patients, contributing to improve their management in real life. The present review aims to update the current state of knowledge on these novel promising LA-ARTs and discusses their implications, particularly from a clinical pharmacokinetics perspective, for the future management and prevention of HIV infection, issues of ongoing importance in the absence of curative treatment or an effective vaccine.

Safety and Benefits of Contraceptives Implants: A Systematic Review

Progestin-only contraceptive implants provide long-acting, highly effective reversible contraception. We searched the medical publications in PubMed, CENTRAL, and EMBASE for relevant articles on hormonal implants published in English between 1990 and 2021. Levonorgestrel (LNG) 6-capsule subdermal implants represented the first effective system approved for reversible contraception. The etonogestrel (ENG) single rod dispositive has been widely employed in clinical practice, since it is a highly effective and safe contraceptive method. Abnormal menstrual bleeding is a common ENG side effect, representing the main reason for its premature discontinuation. Emerging evidence demonstrated that it is possible to extend the use of the ENG implant beyond the three-year period for which it is approved. The ENG implant could be an effective and discrete alternative to the IUD in young girls, such as post-partum/post-abortion. Implants should be inserted by trained skilled clinicians who previously provide adequate counselling about their contraceptive effect, benefits, and any possible adverse events. More studies are needed to validate the extended use of the ENG implant for up to 5 years.

Pharmacokinetics, metabolism and serum concentrations of progestins used in contraception

Many different forms of hormonal contraception are used by millions of women worldwide. These contraceptives differ in the dose and type of synthetic progestogenic compound (progestin) used, as well as the route of administration and whether or not they contain estrogenic compounds. There is an increasing awareness that different forms of contraception and different progestins have different side-effect profiles, in particular their cardiovascular effects, effects on reproductive cancers and susceptibility to infectious diseases. There is a need to develop new methods to suit different needs and with minimal risks, especially in under-resourced areas. This requires a better understanding of the pharmacokinetics, metabolism, serum and tissue concentrations of progestins used in contraception as well as the biological activities of progestins and their metabolites via steroid receptors. Here we review the current knowledge on these topics and identify the research gaps. We show that there is a paucity of research on most of these topics for most progestins. We find that major impediments to clear conclusions on these topics include a lack of standardized methodologies, comparisons between non-parallel clinical studies and variability of data on serum concentrations between and within studies. The latter is most likely due, at least in part, to differences in intrinsic characteristics of participants. The review highlights the importance of insight on these topics in order to provide the best contraceptive options to women with minimal risks.

Pharmacokinetics of Hormonal Contraception in Individuals with Obesity: a Review

Purpose of Review

Obesity continues to affect many women globally. In the USA, almost 40% of all women are obese and many of these women use hormonal contraception for pregnancy prevention. How well hormonal contraceptive works for these individuals has been an area of ongoing research. Pharmacokinetics (PK), the study of drug passage through the body, can shed light on how differences in physiology between obese and non-obese populations can impact drug disposition and subsequent efficacy. This review aims to reflect on these types of studies and empower clinicians with information to help tackle the challenges of the obesity epidemic and help them provide the best contraceptive options to their patients. Here, we present the basics of the mechanisms of action of hormonal contraception, fundamental pharmacokinetic principles, and the latest research into pharmacokinetics, obesity, and hormonal contraception.

Recent Findings

New studies focused on the PK of hormonal contraception in women with obesity have shown that while there are distinct differences in how steroid hormones are processed in women with different body mass indices, contraceptive efficacy is likely the same. This is replicated in studies involving a variety of hormonal contraceptive methods.

Summary

PK studies allow for a detailed analysis of steroid hormone processing in individuals with obesity. Observing PK parameters at each stage of the passage of these hormones through the body, researchers have drilled down on physiologic differences that accompany obesity. In reviewing these PK parameter differences, however, it appears that while processes are different, the end result of pregnancy prevention is likely not compromised in the setting of obesity. Emergency contraception, which functions by a different mechanism from that of continuous hormonal contraception, is the one area in which obesity has been demonstrated to impact efficacy.

Pre- and post-operative counseling for women on hormonal contraceptives receiving sugammadex at an academic hospital

Sugammadex is a steroid binder and can potentially bind the estrogens and progestins contained within hormonal contraception. Therefore, the FDA label for sugammadex contains a drug-drug interaction warning between this medication and hormonal contraception, advising that women taking hormonal contraception use a backup contraceptive method or abstinence for seven days after exposure to sugammadex. However, given concerns that this warning may not be appropriately provided to at-risk patients, we conducted a retrospective chart review to identify women administered sugammadex while using hormonal contraception to identify documented counseling on this drug-drug interaction prior to implementation of a formalized counseling process. We reviewed 1000 randomly selected charts from the University of Colorado Hospital between January 2016 and December 2017. We identified 134 women using hormonal contraception at the time of sugammadex exposure; only one patient (0.7%, 95% CI 0.0, 4.1) had documented counseling. One patient had an unintended pregnancy within the same cycle as her exposure to sugammadex. Improved counseling processes are needed to avoid unnecessary risk for unintended pregnancies.

Etonogestrel Subdermal Implant-Associated Regression of Endometrial Intraepithelial Neoplasia

BACKGROUND

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

CASE

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

CONCLUSION

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

Relationship between patient characteristics and serum etonogestrel concentrations in contraceptive implant users

OBJECTIVE

To determine whether serum etonogestrel concentrations in contraceptive implant users are associated with certain individual patient characteristics.

STUDY DESIGN

We enrolled reproductive-age women using etonogestrel contraceptive implants between 12-36 months duration and measured a single serum etonogestrel concentration. Participants also completed a questionnaire about demographics.

RESULTS

We enrolled 350 participants; median age was 22.5 years (range 18.0-39.1), median months of implant use was 26.0 (range 12.0-36.0), and median body mass index was 25.7 kg/m2 (range 18.5-52.0). Our study population was primarily white/Caucasian (46.6% [163/350]) and Hispanic/Latina ethnicity (51.4% [180/350]). The median serum etonogestrel concentration was 137.4 pg/ml and etonogestrel concentrations varied 12.4 fold in the population (range 55.8-695.1 pg/ml). Using forward stepwise linear regression, months of implant use (β=-1.74, p<.001) and body mass index (β=-3.10, p<.001) were both significantly associated with decreased serum etonogestrel concentration with Black/African American race as a positive effect modifier (β=18.24, p=.099); R-squared for the model=0.13.

CONCLUSIONS

Individuals demonstrated a wide variability in serum etonogestrel concentrations, which can potentially affect side-effect profiles and efficacy. Increasing body mass index and longer duration of implant use were associated with small decreases in serum etonogestrel concentrations, while self-reported Black/African American race was associated with a non-significant increase. Despite these findings, most of etonogestrel variability was unaccounted for, suggesting that other clinical, pharmacologic, and genetic factors contributing to variability in etonogestrel concentrations remain to be determined.

IMPLICATIONS

Although increases in body mass index are associated with lower etonogestrel levels in contraceptive implant users, the majority of women will maintain serum concentrations that consistently suppress ovulation. Furthermore, certain patient characteristics can only explain a small portion (13%) of the variability in serum etonogestrel levels among contraceptive implant users.

Hormonal contraceptive use in Australian women: Who is using what?

BACKGROUND

In Australia many hormonal contraceptives are not Pharmaceutical Benefits Scheme (PBS) supported, hence the use of different formulations have not been quantified.

OBJECTIVES

To document the use of hormonal contraceptives and factors associated with their use.

MATERIALS AND METHODS

Cross-sectional, online questionnaire-based study of 6986 Australian women, aged 18-39 years, recruited by email invitation from two large, representative databases. Main outcome measures were the prevalence of use of hormonal contraceptives and associated socio-demographic characteristics.

RESULTS

Of the 6600 potential hormone contraceptive users, 43.2% were current users. Most (63.6%) reported using a combined oral contraceptive (COC) of which 30.9% were non-PBS-supported anti-androgenic progestin-containing COCs. Use of long-acting reversible contraceptives (LARC) or an injectable contraceptive was reported by 26.8%. Education beyond secondary school, being Australian born, rural residency, normal body mass index, age <25 years and nulliparity were significantly associated with hormonal contraceptive use. Women who reported polycystic ovary syndrome or acne were more likely to be taking a third or fourth generation COC (P < 0.0001) and endometriosis was significantly associated with intrauterine system (IUS) use. Third or fourth generation COC use was reported by 12.1% of obese, current smokers.

CONCLUSION

An estimated one-third of Australian women aged 18-39 are taking a non-PBS-supported anti-androgenic progestin COC, highlighting inequity in access to COC options. That hormonal contraceptive use is higher in rural areas is a novel finding and the proportion of LARC or injectable use suggests that uptake in Australia is higher than previously reported.

[Effectiveness and use of hormonal contraceptives (except for intrauterine devices): CNGOF Contraception Guidelines]

Hormonal contraceptives remain among the most popular methods used by women. The purpose of this work is to review the effectiveness and use of these different methods. In addition, some side-effects are feared and/or frequently reported by users of hormonal contraceptives: unscheduled bleeding, acne, catamenial migraines, weight gain, libido and/or mood disorders. In this review of the literature, the accountability of hormonal contraceptives for the occurrence of some of these side-effects was discussed and a management strategy was proposed.

Ongoing Etonogestrel Contraceptive Implant Use Throughout Pregnancy

Case reports of pregnancies with inadvertent etonogestrel contraceptive implant exposure in the first-trimester have not demonstrated teratogenic risks or adverse pregnancy outcomes. We report the clinical observations of a 15-year-old nulligravida who continued her etonogestrel contraceptive implant throughout pregnancy and delivery, without any adverse maternal or neonatal outcomes. The patient then continued her contraceptive implant as a reliable postpartum contraceptive method. Although her favorable outcomes are consistent with available pharmacologic literature, more data is needed regarding maintenance of a contraceptive implant during a desired pregnancy.

Hormonal Contraception and HIV-1 Acquisition: Biological Mechanisms

Access to effective affordable contraception is critical for individual and public health. A wide range of hormonal contraceptives (HCs), which differ in composition, concentration of the progestin component, frequency of dosage, and method of administration, is currently available globally. However, the options are rather limited in settings with restricted economic resources that frequently overlap with areas of high HIV-1 prevalence. The predominant contraceptive used in sub-Saharan Africa is the progestin-only three-monthly injectable depot medroxyprogesterone acetate. Determination of whether HCs affect HIV-1 acquisition has been hampered by behavioral differences potentially confounding clinical observational data. Meta-analysis of these studies shows a significant association between depot medroxyprogesterone acetate use and increased risk of HIV-1 acquisition, raising important concerns. No association was found for combined oral contraceptives containing levonorgestrel, nor for the two-monthly injectable contraceptive norethisterone enanthate, although data for norethisterone enanthate are limited. Susceptibility to HIV-1 and other sexually transmitted infections may, however, be dependent on the type of progestin present in the formulation. Several underlying biological mechanisms that may mediate the effect of HCs on HIV-1 and other sexually transmitted infection acquisition have been identified in clinical, animal, and ex vivo studies. A substantial gap exists in the translation of basic research into clinical practice and public health policy. To bridge this gap, we review the current knowledge of underlying mechanisms and biological effects of commonly used progestins. The review sheds light on issues critical for an informed choice of progestins for the identification of safe, effective, acceptable, and affordable contraceptive methods.

Safety of hormonal contraception for obese women

INTRODUCTION

Obese women have special safety requirements for contraceptive choice, but the evidence supporting such decision is dispersed and sometimes conflicting. Despite being effective, well tolerated and safe for most women, hormonal contraceptives are underused by obese women due to fear of contraceptive failure, weight gain and venous thrombosis. Areas covered: We performed a comprehensive literature search to identify studies about hormonal contraception in overweight and obese women, including safety concerns. We considered the safety of hormonal contraceptives for otherwise healthy obese women and for those with comorbidities such as hypertension, diabetes, vascular disease, or a history of deep venous thrombosis. Expert opinion: Over time there is no convincing evidence that obesity increases the risk of contraceptive failure. Hormonal contraceptive users may have a modest weight gain that is comparable to that of non-users. Current evidence supports the safe use of combined hormonal contraceptives by obese women after detailed clinical screening to exclude comorbidities that may contraindicate the use of estrogens. Progestin-only methods are generally safe, and long-acting reversible contraceptives hold the best combination of efficacy, safety and convenience for this group, although individualization is advisable.

Efavirenz decreases etonogestrel exposure: a pharmacokinetic evaluation of implantable contraception with antiretroviral therapy

OBJECTIVES

The primary objective of this study was to characterize the pharmacokinetics of etonogestrel (ENG) released from a contraceptive implant in Ugandan women living with HIV who were receiving efavirenz (EFV) or nevirapine (NVP)-based antiretroviral therapy (ART), compared with ART-naive women over 24 weeks.

DESIGN

Nonrandomized, parallel-group study with three arms: ART-naive, NVP, or EFV-based ART (N = 20/group).

METHODS

Sparse pharmacokinetic sampling of ENG, NVP, or EFV were performed at screening, entry, and then 1, 4, 12, and 24-week postimplant insertion. The primary endpoint was ENG concentrations at week 24, compared between the ART-naive group and each ART group, using geometric mean ratio (GMR) with 90% confidence intervals.

RESULTS

Sixty participants competed the 24-week study and data from 58 participants are included; one participant each was excluded from the NVP group and EFV group because of a sample processing error and ART nonadherence, respectively. At week 24, geometric mean ENG was 362, 341, and 66 pg/ml in the ART-naive, NVP, and EFV groups, respectively [GMR: NVP : ART-naive 0.94 (0.90-1.01); EFV : ART-naive 0.18 (0.17-0.20)]. NVP and EFV concentrations were lower at week 24 compared to preimplant [NVP: geometric mean 5.7 versus 6.8 mg/l, respectively, GMR 0.84 (0.83-0.85); EFV: geometric mean 3.6 versus 4.9 mg/l, respectively, GMR 0.73 (0.69-0.80)].

CONCLUSION

After 24 weeks of combined use, ENG exposure was 82% lower in women using EFV-based ART compared with ART-naive women. In contrast, NVP did not significantly impact ENG exposure. These results raise concerns about reduced effectiveness of implantable contraception for women taking EFV-based ART.

Prolonged use of the etonogestrel implant and levonorgestrel intrauterine device: 2 years beyond Food and Drug Administration-approved duration

BACKGROUND

The subdermal contraceptive implant and the 52-mg levonorgestrel intrauterine device are currently Food and Drug Administration approved for 3 and 5 years of use, respectively. Limited available data suggested both of these methods are effective beyond that time. Demonstration of prolonged effectiveness will improve the cost-effectiveness of the device, and potentially patient continuation and satisfaction.

OBJECTIVE

We sought to evaluate the effectiveness of the contraceptive implant and the 52-mg hormonal intrauterine device in women using the method for 2 years beyond the current Food and Drug Administration-approved duration.

STUDY DESIGN

We initiated this ongoing prospective cohort study in January 2012. We are enrolling women using the contraceptive implant or 52-mg levonorgestrel intrauterine device for a minimum of 3 and 5 years, respectively (started intrauterine device in ≥2007 or implant in ≥2009). Demographic and reproductive health histories, as well as objective body mass index, were collected. Implant users were offered periodic venipuncture for analysis of serum etonogestrel levels. The primary outcome, unintended pregnancy rate, was calculated per 100 woman-years. We analyzed baseline demographic characteristics using χ² test and Fisher exact test, and compared serum etonogestrel levels stratified by body mass index using the Kruskal-Wallis test.

RESULTS

Implant users (n = 291) have contributed 444.0 woman-years of follow-up. There have been no documented pregnancies in implant users during the 2 years of postexpiration follow-up. Calculated failure rates in the fourth and fifth years for the implant are calculated as 0 (1-sided 97.5% confidence interval, 0-1.48) per 100 woman-years at 4 years and 0 (1-sided 97.5% confidence interval, 0-2.65) per 100 woman-years at 5 years. Among 496 levonorgestrel intrauterine device users, 696.9 woman-years of follow-up have been completed. Two pregnancies have been reported. The failure rate in the sixth year of use of the levonorgestrel intrauterine device is calculated as 0.25 (95% confidence interval, 0.04-1.42) per 100 woman-years; failure rate during the seventh year is 0.43 (95% confidence interval, 0.08-2.39) per 100 woman-years. Among implant users with serum etonogestrel results, the median etonogestrel level was 207.7 pg/mL (range 63.8-802.6 pg/mL) at the time of method expiration, 166.1 pg/mL (range 67.9 25.0-470.5 pg/mL) at the end of the fourth year, and 153.0 pg/mL (range 72.1-538.8 pg/mL) at the end of the fifth year. Median etonogestrel levels were compared by body mass index at each time point and a statistical difference was noted at the end of 4 years of use with overweight women having the highest serum etonogestrel (195.9; range 25.0-450.5 pg/mL) when compared to normal (178.9; range 87.0-463.7 pg/mL) and obese (137.9; range 66.0-470.5 pg/mL) women (P = .04).

CONCLUSION

This study indicates that the contraceptive implant and 52-mg hormonal intrauterine device continue to be highly effective for at least 2 additional years of use. Serum etonogestrel evaluation demonstrates median levels remain above the ovulation threshold of 90 pg/mL for women in all body mass index classes.

Hormonal contraception and obesity

The rising rate of overweight and obesity is a public health crisis in the United States and increasingly around the globe. Rates of contraceptive use are similar among women of all weights, but because contraceptive development studies historically excluded women over 130% of ideal body weight, patients and providers have a gap in understanding of contraceptive efficacy for obese and overweight women. Because of a range of drug metabolism alterations in obesity, there is biologic plausibility for changes in hormonal contraception effectiveness in obese women. However, these pharmacokinetic changes are not linearly related to body mass index or weight, and it is unknown what degree of obesity begins to affect pharmacokinetic or pharmacodynamics processes. Overall, most studies of higher quality do not demonstrate a difference in oral contraceptive pill effectiveness in obese compared with non-obese women. However, data are scant for women in the highest categories of obesity, and differences by progestin type are incompletely understood. Effectiveness of most non-oral contraceptives does not seem to be compromised in obesity. Exceptions to this include the combined hormonal patch and oral levonorgestrel emergency contraception, which may have lower rates of effectiveness in obese women. The purpose of this review is to summarize evidence on contraceptive use in women with obesity, including differences in steroid hormone metabolism, contraceptive effectiveness, and safety, compared with women of normal weight or body mass index using the same methods.

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.

Clarification of contraceptive drug pharmacokinetics in obesity

Related to concerns about the role of obesity in the efficacy of contraceptive drugs, a review of the literature was carried out in regard to the pharmacokinetics of ethinyl estradiol and various progestins given by various routes of administration. Most studies show that obese women exhibit modestly lower plasma concentrations of these drugs (circa 30%) when given the same doses as normal-weight women. While the mechanism is uncertain, precedence in the literature suggests that this is due to body weight-related differences in metabolism rates. Confusing in some of the literature is that a few studies have reported erroneously calculated pharmacokinetic parameters after multiple dosing of oral contraceptives. A demonstration of appropriate pharmacokinetic methodology is provided.

[Safety profile of etonogestrel contraceptive implant (Nexplanon® and Implanon®) reported in France]

OBJECTIVES

The aim of the study was to assess the incidence of adverse effects (AE) reported with etonogestrel contraceptive implant in France (Implanon^® and Nexplanon^®).

MATERIALS AND METHODS

All cases of AE or unintended pregnancies reported to health authorities or to the firm were analyzed.

RESULTS

During 10 years, 5433 AE and 789 unintended pregnancies were reported. Only 388 (7 %) were serious. There were 1137 reports of difficulties to remove, failure to locate or migration, 430 of insertion difficulties and 203 of deformation or expulsion of the implant. Among other AE, the most common were 1694 gynecological AE, 524 skin reactions and 437 metabolic AE. Since the marketing of Nexplanon^® which causes less deep insertions, the incidence of migrations, removal or insertion difficulties has decreased overall (0.92 vs. 1.31/1000 patients), particularly the incidence of removal difficulties, location failures or migrations (0.12 vs 1.01/1000). The infrequent but serious AE were infectious complications at the implant site and pregnancies. When the circumstances of the pregnancy were known, the contraceptive failure was due to the apparent inefficiency of the implant (n=224), to a technique failure (n=203) or to a drug-drug interaction (n=59).

CONCLUSION

This study confirms that AE of this implant are frequent but not serious, except for the pregnancies. The incidence of complications related to insertion decreased with Nexplanon^®. Among other preventable AE, unintended pregnancies due to a drug-drug interaction would require to be better known by the practitioner.

Relationship between etonogestrel level and BMI in women using the contraceptive implant for more than 1 year

Progestin-only contraceptive methods, including the 3-year, single-rod etonogestrel (ENG) implant, may be preferred for obese women to avoid additional estrogen-related thrombosis risk; however, whether obese women receive an ENG sufficient dose to suppress ovulation is understudied. Our analysis expands on the limited information currently available by studying ENG levels related to body mass index (BMI) in a community sample of primarily Hispanic women. This cross-sectional, descriptive study of 52 long-term implant users found comparable ENG levels across a wide BMI range (p=.1). These results further support that ENG levels are independent of BMI through 3 years of implant use and are thus reassuring that ENG implants will be effective for women of all BMIs.

[Contraception and obesity]

The prevalence of obesity is increasing massively over several decades in industrialized countries. Obese women are sexually active but they use fewer contraceptive methods and are at high risk of unintended pregnancy. In addition, obesity is an important risk factor for venous thromboembolism events and arterial thrombosis (myocardial infarction and ischemic stroke). All of these data are to be considered in choosing a contraceptive method for obese women. Except depot medroxyprogesterone acetate injection, the progestin-only contraceptives (progestin only pills and etonogestrel subdermal implant) and the intra-uterine devices are the preferred contraceptive methods in obese women. The combined estrogen-progestin contraceptives (pill, patch and vaginal ring) may be proposed in very strict conditions (no other associated vascular risk factor). Obesity does not increase the risk of failure of most contraceptive methods. Bariatric surgery is a complex situation. It requires to program a possible pregnancy and contraception is needed for several months. Some bariatric surgical techniques such as by-pass can induce gastrointestinal malabsorption. In this situation, all oral contraceptives are not recommended because of a higher risk of failure.

A Review of the Toxicologic Implications of Obesity

The increasing prevalence of obesity in developed nations has far-reaching implications for medical toxicology. The management of obese patients is complicated by comorbid illnesses, changes in cardiovascular and respiratory physiology, alterations in pharmacokinetics, and a lack of studies to identify appropriate dosing for current therapeutics and antidotes. In this review article, we examine obesity-associated physiologic and pharmacokinetic changes that may increase the vulnerability of obese patients to overdose. Further research is needed to characterize the relationship between drug toxicity and obesity.

Use of the etonogestrel implant and levonorgestrel intrauterine device beyond the U.S. Food and Drug Administration-approved duration

OBJECTIVE

To evaluate the effectiveness of the contraceptive implant and the 52-mg hormonal intrauterine device (IUD) in women using the method beyond the current U.S. Food and Drug Administration (FDA)-approved duration of 3 and 5 years, respectively.

METHODS

Women willing to continue using their implant or 52-mg levonorgestrel IUD beyond the FDA-approved duration were followed prospectively for contraceptive effectiveness. Unintended pregnancy rate per 100 women-years was calculated. Implant users are offered periodic venipuncture for analysis of serum etonogestrel levels. The Kruskal-Wallis test was used to compare the etonogestrel levels across body mass index (BMI) groups.

RESULTS

Implant users (n=237) have contributed 229.4 women-years of follow-up, with 123 using the etonogestrel implant for 4 years and 34 using it for 5 years. Zero pregnancies have been documented, for a failure rate of 0 (one-sided 97.5% confidence interval [CI] 0-1.61) per 100 women-years. Among 263 levonorgestrel IUD users, 197.7 women-years of follow-up have been completed. One pregnancy was confirmed, for a failure rate of 0.51 (95% CI 0.01-2.82) per 100 women-years. Among implant users with serum etonogestrel results, the median and range of etonogestrel level at 3 years of use was 188.8 pg/mL (range 63.8-802.6 pg/mL) and 177.0 pg/mL (67.9-470.5 pg/mL) at 4 years of use. Etonogestrel levels did not differ by BMI at either time point (3 years: P=.79; 4 years: P=.47).

CONCLUSION

Preliminary findings indicate the contraceptive implant and 52-mg hormonal IUD continue to be highly effective for an additional year beyond the FDA-approved 3 and 5 years. Serum etonogestrel levels indicate the implant contains adequate hormone for ovulation suppression at the end of both 3 and 4 years of use.

LEVEL OF EVIDENCE

II.

Obesity and menstrual disorders

Obese women often present with oligomenorrhoea, amenorrhoea or irregular periods. The association between obesity and heavy menstrual bleeding is not well documented and data on its prevalence are limited. While the investigation protocols should be the same as for women of normal weight, particular focus is required to rule out endometrial hyperplasia in obese women. The treatment modalities of menstrual disorders for obese women will be, in principle, similar to those of normal weight. However, therapeutic outcomes in terms of effectiveness and adverse outcomes need special consideration when dealing with women with a high body mass index (BMI). Here, different treatment strategies are reviewed paying particular attention to the effect of weight on their efficacy and the challenges of providing each treatment option. This chapter aims to review the current literature and address areas where further evidence is needed, which will subsequently influence clinical practice.

Contraception and sexual health in obese women

As the proportion of women with obesity increases worldwide, understanding the influence of body weight on sexual behavior, fertility, and contraceptive effectiveness is critical for health-care professionals and patients. Although many have theorized that obese women are different from normal-weight women regarding sexual health and behavior, current evidence for the most part disproves this. The exception is in adolescents where body image may play a role in riskier behavior, placing them at a greater risk of an unintended pregnancy. Given that most modern contraceptives were not originally evaluated in obese women, understanding how weight affects contraceptive pharmacokinetics and efficacy should be a focus of ongoing research. Evidence is reassuring that most modern contraceptive methods are safe and effective in obese women. This paper reviews what is known about sexual and contraceptive behavior, as well as the effectiveness and pharmacokinetics of modern contraceptives, for overweight and obese women.

Obesity and contraception

Utilizing contraception is critical in preventing unintended pregnancies among obese women. However, clinicians and obese patients may be unclear about which contraceptive methods are optimal. This review discusses the literature on any weight gain associated with contraceptive use, contraceptive efficacy among obese women, and special considerations for contraceptive method selection for women after bariatric surgery. The review also covers new findings on oral emergency contraception and obesity.

Superoxide dismutase 1 overexpression in mice abolishes maternal diabetes-induced endoplasmic reticulum stress in diabetic embryopathy

OBJECTIVE

Both oxidative stress and endoplasmic reticulum stress (ER stress) are causal events in diabetic embryopathy. We tested whether oxidative stress causes ER stress.

STUDY DESIGN

Wild-type (WT) and superoxide dismutase 1 (SOD1)-overexpressing day 8.75 embryos from nondiabetic WT control with SOD1 transgenic male and diabetic WT female with SOD1 transgenic male were analyzed for ER stress markers: C/EBP-homologous protein (CHOP), calnexin, eukaryotic initiation factor 2α (eIF2α), protein kinase ribonucleic acid (RNA)-like ER kinase (PERK), binding immunoglobulin protein, protein disulfide isomerase family A member 3, kinases inositol-requiring protein-1α (IRE1α), and the X-box binding protein (XBP1) messenger RNA (mRNA) splicing.

RESULTS

Maternal diabetes significantly increased the levels of CHOP, calnexin, phosphorylated (p)-eIF2α, p-PERK, and p-IRE1α; triggered XBP1 mRNA splicing; and enhanced ER chaperone gene expression in WT embryos. SOD1 overexpression blocked these diabetes-induced ER stress markers.

CONCLUSION

Mitigating oxidative stress via SOD1 overexpression blocks maternal diabetes-induced ER stress in vivo.

Obesity and hormonal contraceptive efficacy

Obesity is a major public health concern affecting an increasing proportion of reproductive-aged women. Avoiding unintended pregnancy is of major importance, given the increased risks associated with pregnancy, but obesity may affect the efficacy of hormonal contraceptives by altering how these drugs are absorbed, distributed, metabolized or eliminated. Limited data suggest that long-acting, reversible contraceptives maintain excellent efficacy in obese women. Some studies demonstrating altered pharmacokinetic parameters and increased failure rates with combined oral contraceptives, the contraceptive patch and emergency contraceptive pills suggest decreased efficacy of these methods. It is unclear whether bariatric surgery affects hormonal contraceptive efficacy. Obese women should be offered the full range of contraceptive options, with counseling that balances the risks and benefits of each method, including the risk of unintended pregnancy.

Contraception and the obese woman

PURPOSE

Obesity has reached epidemic rates among U.S. women of reproductive age, many of whom want to use contraception. However, some forms of contraception can have adverse effects on an obese woman's health. This article explores risks of contraception available in the United States and provides clinical recommendations for use by obese women.

DATA SOURCES

Information was compiled by reviewing the scientific literature on contraception and female obesity using CINAHL, MEDLINE, PubMed search engines.

CONCLUSIONS

The evidence is largely supportive of combined oral contraceptive (COC) use in carefully screened obese women without known risks factors for cardiovascular disease. The efficacy of COCs may be slightly reduced in obese women because of increased body mass. Other types of hormonal contraceptives have varying safety and efficacy reports when used by obese women. Intrauterine devices do not have reduced efficacy nor increased risks for obese women but insertion may be more difficult. Obesity has no effect on efficacy of barrier methods of contraception.

IMPLICATIONS

Clinicians should conduct a careful history and physical exam with selected supporting laboratory tests when considering prescription of hormonal contraceptives for obese women. Obese women require health counseling to carefully follow directions for contraceptive use to avoid unintended pregnancy.

Obesity and oral contraceptives: a clinician's guide

Obesity and unintended pregnancy are two of the major health epidemics we are currently facing worldwide. Patient education is a clinician's greatest tool in combating both epidemics but many clinicians may be uncomfortable with counselling and prescribing contraception for obese women. Overall, the prevention of unintended pregnancy in obese women far outweighs any risk associated with oral contraceptive use. This review aims to provide the clinician with a practical guide to the use of oral contraceptive pills in obese women.