Prolonged monitoring of ethinyl estradiol and levonorgestrel levels confirms an altered pharmacokinetic profile in obese oral contraceptives users

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.

Weight Loss During Intrauterine Progestin Treatment for Obesity-associated Atypical Hyperplasia and Early-Stage Cancer of The Endometrium

Intrauterine progestin is a treatment option for women with atypical hyperplasia or low-risk endometrial cancer who wish to preserve their fertility, or whose poor surgical fitness precludes safe hysterectomy. We hypothesized that in such women with obesity, weight loss during progestin treatment may improve oncological outcomes. We conducted a prospective nonrandomized study of women with obesity and atypical hyperplasia or low-grade stage 1a endometrial cancer undergoing progestin treatment. Women with a body mass index (BMI) ≥ 35 kg/m2 were offered bariatric surgery; those who declined and those with a BMI of 30 to 34.9 kg/m2 were encouraged to lose weight by low-calorie diet. We assessed uptake of bariatric surgery; weight lost during progestin treatment; and the impact of more than 10% total body weight loss on progestin treatment response at 12 months. 71 women [median age 58 years (interquartile range; IQR 35-65); mean BMI 48 kg/m2 (SD 9.3)] completed the study. Twenty-three women (32%) had bariatric surgery, on average 5 months (IQR 3-8) after progestin treatment commenced. Weight change during progestin treatment was -33.4 kg [95% confidence interval (CI) -42.1, -24.7] and -4.6 kg (95% CI -7.8, -1.4) in women receiving bariatric surgery and low-calorie diet, respectively (P < 0.001). Forty-three women (61%) responded to progestin, while 23 (32%) showed stabilized and 5 (7%) progressive disease. Response at 12 months was not predicted by age or baseline BMI, but women who lost more than 10% of their total body weight were more likely to respond to progestin than those who did not (adjusted odds ratio 3.95; 95% CI 1.3, 12.5; P = 0.02). Thus weight loss may improve oncological outcomes in women with obesity-associated endometrial neoplastic abnormalities treated with progestin. PREVENTION RELEVANCE: This study found that weight loss improves response rates in women with obesity and atypical hyperplasia or low-risk endometrial cancer undergoing conservative management with intrauterine progestin. Given the additional benefits of weight loss for fertility, cardiovascular health and quality of life, future research should focus on how best to accomplish it.

Contraceptive use among women through their later reproductive years: Findings from an Australian prospective cohort study

Objective

Examine patterns of contraceptive use and contraceptive transitions over time among an Australian cohort of women through their later reproductive years.

Study design

Latent Transition Analysis was performed using data on 8,197 women from the Australian Longitudinal Study on Women’s Health’s 1973–78 cohort to identify distinct patterns of contraceptive use across 2006, 2012 and 2018. Women were excluded from the analysis at time points where they were not at risk of an unintended pregnancy. Latent status membership probabilities, item-response probabilities, transitions probabilities and the effect of predictors on latent status membership were estimated and reported.

Results

Patterns of contraceptive use were relatively consistent over time, particularly for high efficacy contraceptive methods with 71% of women using long-acting reversible contraceptives in 2012 also using long-acting reversible contraceptives in 2018. Multiple contraceptive use was highest in 2006 when women were aged 28–33 years (19.3%) but declined over time to 14.3% in 2018 when women were aged 40–45 years. Overall, contraceptive patterns stabilised as the women moved into their late 30s and early 40s.

Conclusions

Although fertility declines with age, the stability of contraceptive choice and continued use of short-acting contraception among some women suggests that a contraceptive review may be helpful for women during perimenopause so that they are provided with contraceptive options most appropriate to their specific circumstances.

Trends in oral contraceptive and intrauterine device use among reproductive-aged women in the US from 1999 to 2017

PURPOSE

Since the 1960s, increasing oral contraceptive (OC) use has mirrored decreasing ovarian cancer incidence. The impact of intrauterine devices (IUDs) on cancer risk is less well established. With improved access and increased options, we must consider how changing usage can affect cancer risks.

METHODS

Nationally representative data from the National Health and Nutrition Examination Survey (NHANES, 1999-2016) and the National Survey for Family Growth (NSFG, 2006-2017) were used to evaluate contraceptive use over time in premenopausal women (NHANES n = 13,179; NSFG n = 26,262). Trends were assessed overall and by race, age, pregnancy history, education, and body mass index.

RESULTS

The average annual absolute increase in self-reported IUD use was 0.81% (NSFG), while OC use decreased 0.49% in NSFG and 0.47% in NHANES. This represents a significant decrease in OC use in NSFG [annual percent change (APC) - 2.2% (95% CI - 3.4, - 1.0%), p < 0.01]. Trends in OC use varied somewhat by pregnancy history in NHANES (p-interaction = 0.054). In contrast, IUD use increased 6.2% annually [(1.4, 11.2%), p = 0.03] and varied significantly by pregnancy history (p-interaction < 0.01). Nulligravid women increased IUD use 11.0% annually [(2.6, 20.1%), p = 0.02] compared to women with prior pregnancy at 5.2% [(0.4, 10.2%), p = 0.04]. In 2015-2017, IUD use was 76.5% hormonal (71.1, 81.8%) and 22.9% copper (17.4, 28.3%) with greater hormonal IUD use in obese women [89.4%, (82.9, 95.9%)].

CONCLUSION

Increasing IUD use outpaced declining OC use in premenopausal US women. There may be a resulting decreased gynecologic cancer risk as more women gain access to potentially risk-reducing contraceptives.

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.

Obesity and hormonal contraception: an overview and a clinician's practical guide

BACKGROUND

The growing prevalence of obesity among the fertile female population poses a considerable problem to contraceptive providers. Obese women, who are more at risk for venous thromboembolism and cardiovascular events due to their condition, might be at an even higher risk of developing thromboembolic events when on medical contraception. Combined hormonal contraceptives might be less effective in obese women and may lead to unacceptable metabolic side effects for this population. In addition, the lack of safety data for weight loss drugs and the higher risk for complications during and after pregnancy require a close surveillance of the fertility status of obese patients.

OBJECTIVE

The aim of this narrative review is to summarize the available medical contraceptive options and to give the readers a practical guidance for a wise contraceptive choice with regards to obesity.

METHODS

A general literature review of peer-reviewed publications on the topic "obesity and contraception" was performed using the PubMed database.

RESULTS

Nowadays, there are many useful tools that help clinicians in choosing among the wide range of therapeutic possibilities, such as the World Health Organization (WHO) Medical Eligibility Criteria for contraceptive use. Furthermore, the great diversity of hormonal contraceptive formulations (combined hormonal formulations; progestin-only methods) and active substances (different estrogens and progestins) allow physicians to tailor therapies to patients' clinical peculiarities.

CONCLUSION

Long-acting reversible contraceptives [progestin-only implants, levonorgestrel-intra-uterine devices (IUDs) and copper IUDs] and progestin-only methods in general are excellent options for many categories of patients, including obese ones.

LEVEL OF EVIDENCE

V, narrative review.

Contraceptive Options Following Gestational Diabetes: Current Perspectives

Gestational diabetes mellitus (GDM) complicates approximately 7% of pregnancies in the United States. Along with risk factors related to pregnancy, women with a history of GDM also have an increased risk of developing type 2 diabetes mellitus later in life. These women require special consideration when discussing contraception and other reproductive health issues. GDM carries a category 1 rating in the US Medical Eligibility Criteria for all contraceptive methods, which supports safety of the various methods but does not account for effectiveness. Contraceptive options differ in composition and mechanisms of action, and concerns have been raised about possible effects of contraception on metabolism. Clinical evidence is limited to suggest that hormonal contraception has significantly adverse effects on body weight, lipid, or glucose metabolism. In addition, the majority of evidence does not suggest a relationship between development of type 2 diabetes mellitus and use of hormonal contraception. Data are limited, so it is challenging to make a broad, general recommendation regarding contraception for women with a history of GDM. A woman’s history of GDM should be considered during contraceptive counseling. Discussion should focus on potential medical comorbidities and the implications of GDM on future health, with special consideration of issues including bone health, obesity, cardiovascular disease, and thrombosis risk. Providers must emphasize the importance of reliable, highly effective contraception for women with GDM, to optimize the timing of future pregnancies. This approach to comprehensive counseling will guide optimal decision-making on contraceptive use, lifestyle changes, and planning of subsequent pregnancies.

ACOG Practice Bulletin No. 206: Use of Hormonal Contraception in Women With Coexisting Medical Conditions

Although numerous studies have addressed the safety and effectiveness of hormonal contraceptive use in healthy women, data regarding women with underlying medical conditions or other special circumstances are limited. The U.S. Medical Eligibility Criteria (USMEC) for Contraceptive Use, 2016 (), which has been endorsed by the American College of Obstetricians and Gynecologists, is a published guideline based on the best available evidence and expert opinion to help health care providers better care for women with chronic medical problems who need contraception. The goal of this Practice Bulletin is to explain how to use the USMEC rating system in clinical practice and to specifically discuss the rationale behind the ratings for various medical conditions. Contraception for women with human immunodeficiency virus (HIV) (); the use of emergency contraception in women with medical coexisting medical conditions, including obesity, (); and the effect of depot medroxyprogesterone acetate (DMPA) on bone health () are addressed in other documents from the American College of Obstetricians and Gynecologists.

Effects of ritonavir-boosted protease inhibitors on combined oral contraceptive pharmacokinetics and pharmacodynamics in HIV-positive women

OBJECTIVE

To assess the pharmacokinetics of combined oral contraceptive (COC) components and prevalence of ovulation in HIV-positive women using ritonavir-containing antiretroviral regimens compared to those using regimens previously found not to interact with COCs or not using any antiretrovirals.

STUDY DESIGN

We conducted a prospective cohort pharmacokinetic pilot study comparing the pharmacokinetics of levonorgestrel (LNG) and ethinyl estradiol (EE) in HIV-positive women taking ritonavir-containing antiretroviral regimens to those in women using non-ritonavir-containing regimens or no antiretrovirals. Participants received COCs containing LNG/EE 150/30 mcg for 21 days. Beginning day 21, we collected serial blood samples over 72 h. The primary outcome was area under the curve (AUC) of LNG, with secondary outcomes including other LNG pharmacokinetic measures, EE pharmacokinetics and ovulation as measured by serum progesterone.

RESULTS

Pharmacokinetic parameters of LNG showed a trend toward increased exposure in women on ritonavir. LNG AUClast increased by 32.6% (312±60.9 vs. 243±82.6 ng/mL*h, p=.033, n=5) in women taking ritonavir compared to the control group (n=10). The Cmax (9.68±1.81 vs. 7.62±2.29 ng/mL) and Cmin (4.97±1.15 vs. 3.70±1.29 ng/mL) were also higher in the ritonavir arm. After excluding the inconsistent users (n=2), CL of LNG was reduced in the ritonavir arm (p=.032). EE pharmacokinetic profiles were not different between groups. The progesterone concentrations were similar in women of both groups, and none were consistent with ovulation during the treatment cycle.

CONCLUSION

Women on ritonavir showed an approximately 30% increase in LNG exposure but no difference in EE exposure.

IMPLICATIONS

The current data suggest that ritonavir does not have a clinically significant impact on oral contraceptive pharmacokinetics.

Patterns of prescription and discontinuation of contraceptives for Swedish women with obesity and normal-weight women

Purpose: This study aimed to explore the prescription of different contraceptive methods to Swedish women with obesity and to compare the pattern of prescription and adherence to treatment between this group and normal-weight women. Materials and methods: This study included 371 women with obesity and 744 matched normal-weight women, aged 18-40. Medical records were scrutinised for the period 1 January 2010 to 31 December 2014. The retrieved variables included: background characteristics, prescribed contraceptive methods, adverse effects, duration of treatment, reason for discontinuation and bleeding pattern. Result: Progestin-only pills were mainly prescribed to women with obesity (44% vs. 20%, p = 0.001) whereas combined hormonal contraception was mainly prescribed to normal-weight women (60% vs. 21%, p < 0.0001). Thirty-three percent vs. 25% (p = 0.003) discontinued their contraceptive method within 1 year. The most commonly declared reason for discontinuation was bleeding disturbance (14.7% vs. 9.6%, p = 0.008). Conclusion: The most commonly prescribed contraceptive method in women with obesity was progestin-only pills, but surprisingly many women with obesity were prescribed combined hormonal contraception despite current Swedish and European guidelines. Incident users with obesity were significantly more likely to discontinue their contraceptive method within the first year of the study period, compared with incident normal-weight users.

Altered pharmacokinetics of combined oral contraceptives in obesity - multistudy assessment

OBJECTIVE

The objective was to evaluate the pharmacokinetics (PKs) of levonorgestrel (LNG)-containing combined oral contraceptives (COCs) in obese women.

STUDY DESIGN

We pooled and reanalyzed data from 89 women with different body mass index (BMI) categories from four clinical studies. The LNG and ethinyl estradiol (EE) PKs were analyzed utilizing a zero-order absorption (K0), two-compartment PK model to evaluate key PK parameters in relation to a range of weights, BMI and body surface area (BSA).

RESULTS

Increasing of body habitus metrics is correlated with decreasing Cmax (p<.0001) and AUCτ (p<.05) for both LNG and EE, but no correlation was found for Cmin (p≥.17). Increasing weight and BMI were associated with a modest increase (p≤.056) of clearance (CL) and appreciable increases of central volume (V1, p<.05), distribution clearance (CLd, p≤.001) and peripheral volume (V2, p<.0001) for LNG. For EE, increases in CL (p≤.009) were found with greater weight, BMI and BSA. Values of V1, CLd and V2 also increased (p<.0001) in obese subjects. The half-life and steady-state volume were greater among obese women (p<.0001) for both LNG and EE. LNG and EE PK parameters correlated well (p≤.006 for all), indicating that individual subject physiology affected both drugs similarly.

CONCLUSIONS

The primary effects of obesity on LNG and EE were a modest increase in CL and a marked increase in distribution parameters. We observed no obesity-related differences in trough LNG and EE concentrations.

IMPLICATIONS

This population PK analysis demonstrated reduced systemic exposure to LNG/EE oral contraceptives in obese subjects (Cmax and AUCτ); these particular differences are unlikely to lower contraceptive effectiveness among obese women who are correctly using LNG-containing contraceptives.

Effectiveness of progestin-based therapy for morbidly obese women with complex atypical hyperplasia

OBJECTIVE

While progestins can effectively treat women with complex atypical hyperplasia (CAH), the impact of body habitus on treatment outcome is not well studied. We examine the association between body mass index (BMI) and progestin treatment outcomes.

METHODS

We conducted a retrospective cohort study of patients diagnosed with hyperplasia between 2003 and 2011. Demographics, past medical history, BMI, hormonal therapy, and histologic treatment response were abstracted. Patients with CAH who received progestin therapy were examined, and rates of regression were assessed.

RESULTS

Of 623 patients identified, 117 had CAH and satisfied the inclusion criteria. Median age was 34, and nearly, two-thirds (64%) were nulliparous. Mean BMI was 40.2, and 81% were obese (BMI 30-39.9: 36%, BMI ≥ 40: 45%). 103 patients (88%) received systemic progestin therapy and 14 patients (12%) received levonorgestrel-releasing intrauterine devices (LNG-IUS). 47 patients (40%) had a complete response to progestin-based therapy. BMI had no effect on the rate of complete response. The proportions of CAH patients with complete regression after hormonal therapy were BMI < 30: 39%, 30-39.9: 40%, and ≥ 40: 36% (P = 0.73). Women treated with LNG-IUS displayed higher rates of complete regression than those receiving systemic therapy (62% versus 38%, P = 0.096), and those with class III obesity were more likely than non-obese patients to receive LNG-IUS although neither reached statistical significance (< 40: 6.7% versus ≥ 40: 17%, P = 0.09).

CONCLUSION

In this morbidly obese population, response to progestin therapy was generally low; body habitus did not impact treatment outcome for CAH, but local therapy may be more effective than systemic therapy.

Contraceptive Care of Obese Women

Importance

In the United States, 27% of reproductive-aged women are overweight, and 35% are obese. Until recently, contraceptive research excluded women greater than 130% of their ideal body weight. Gaps in data limit evidence-based decision making for effective contraceptive counseling and management in this rapidly growing population.

Objectives

The aims of this summary are to review the benefits, adverse effects, and risk factors associated with contraceptive methods in obese women, with special attention to effectiveness, and provide contraceptive management and counseling recommendations for best clinical practice.

Evidence Acquisition

We performed a thorough search of PubMed for current literature, including original research articles, review articles, and guidelines on contraceptive counseling and management in obese women in the United States. We reviewed the body of evidence with special attention to studies published since recent Cochrane and systematic reviews on this topic.

Conclusions

Contraceptive use is safer than pregnancy, especially for obese women who have increased pregnancy risks. Baseline health is compromised by obesity, but contraceptive risks remain low. Long-acting, reversible contraceptive methods offer superior effectiveness, minimal risk, and numerous noncontraceptive benefits across body mass index groups. No substantial evidence supports ineffectiveness of any method in obese women except oral emergency contraception and the patch. Pharmacokinetic changes of obesity associated with other oral methods do not seem to result in clinically significant declines in effectiveness. Future contraceptive efficacy studies should include obese women to better discuss their contraceptive needs.

Relevance

This review is beneficial for all providers caring for reproductive-aged women wanting to avoid unintended pregnancy.

Are hormonal contraceptives less effective in overweight and obese women?

Loss of efficacy of hormonal contraceptives is of particular concern for women who are overweight or obese. Only recently have clinical trials started to include overweight and obese women in their study populations, limiting the data available on which to make the best prescribing decisions for hormonal contraceptives for these patients. Other methods, such as the copper or levonorgestrel-containing intrauterine device, the etonogestrel implant, and depot medroxyprogesterone acetate, are preferred over combined oral contraceptives, the transdermal patch, and the vaginal ring.

17-β-Estradiol induces spreading depression and pain behavior in alert female rats

AIMS

Test the putative contribution of 17-β-estradiol in the development of spreading depression (SD) events and head pain in awake, non-restrained rats.

MAIN METHODS

Female, Sprague-Dawley rats were intact or underwent ovariectomy followed one week later by surgery to place electrodes onto the dura to detect epidural electroencephalographic activity (dEEG). dEEG activity was recorded two days later for 12 hours after systemic administration of 17-β-estradiol (180 μg/kg, i.p.). A separate set of rats were observed for changes in exploratory, ambulatory, fine, and rearing behaviors; periorbital allodynia was also assessed.

KEY FINDINGS

A bolus of 17-β-estradiol significantly elevated serum estrogen levels, increased SD episodes over a 12-hour recording period and decreased rearing behaviors in ovariectomized rats. Pre-administration of ICI 182,780, an estrogen receptor antagonist, blocked 17-β-estradiol-evoked SD events and pain behaviors; similar results were observed when the antimigraine therapeutic sumatriptan was used.

SIGNIFICANCE

These data indicate that an estrogen receptor-mediated mechanism contributes to SD events in ovariectomized rats and pain behaviors in both ovariectomized -and intact- rats. This suggests that estrogen plays a different role in each phenomenon of migraine where intense fluctuations in concentration may influence SD susceptibility. This is the first study to relate estrogen peaks to SD development and pain behaviors in awake, freely moving female rats, establishing a framework for future preclinical migraine studies.

Levonorgestrel butanoate intramuscular injection does not reliably suppress ovulation for 90 days in obese and normal-BMI women: a pilot study

BACKGROUND

We performed a pilot evaluation of a new formulation of levonorgestrel butanoate (LB) designed to be a long-acting injectable (6 months) contraceptive to determine pharmacodynamic end points in normal-body mass index (BMI) and obese women.

STUDY DESIGN

Obese (BMI ≥30 kg/m2) and normal-BMI, otherwise healthy, women received a single intramuscular injection of LB after ovulation was confirmed in a baseline cycle. The primary outcome was return of ovulation in days.

RESULTS

A total of 14 women enrolled and completed the study [normal BMI n=9, median BMI 22.7kg/m2 (range 19.4-25.8); obese n=5, median BMI 35.7kg/m2 (30.1-39.2)]. The first 6 subjects (normal BMI=4/9, obese BMI=2/5) received 40 mg of LB, and the remaining 8 received 20 mg. All women except one returned to ovulation prior to 6 months. Return to ovulation occurred earlier in the obese group; 3/5 obese and 0/9 normal BMI subjects returned to ovulation within 90 days (p=.03). No serious adverse events were reported during the study.

CONCLUSION

Return to ovulation was earlier than 6 months in both BMI groups but more so in the obese BMI group.

IMPLICATIONS

Since return of ovulation was earlier than expected for this LB injectable formulation, additional steps are needed to develop a preparation suitable as a longer-lasting product.

Fertility and combined oral contraceptives - unintended pregnancies and planned pregnancies following oral contraceptive use - results from the INAS-SCORE study

OBJECTIVES

To estimate the real-use contraceptive effectiveness of the combined oral contraceptive containing dienogest and estradiol valerate (DNG/EV) and whether DNG/EV compared to other combined oral contraceptives (oCOC) has a negative effect on return to fertility.

METHODS

Transatlantic, prospective, non-interventional cohort study conducted in the USA and seven European countries with two main exposure groups and one exposure subgroup: new users of DNG/EV and other COC (oCOC), particularly levonorgestrel-containing COCs (LNG). In a planned secondary analysis, pregnancy outcomes were investigated including contraceptive effectiveness and pregnancy following contraceptive cessation. The influence of age, parity and OC-type were assessed.

RESULTS

50,203 COC users were followed for 105,761 woman-years (WY). There were 677 unintended pregnancies reported: 451 in the USA and 226 in Europe. The contraceptive failure rate in Europe was 0.5 events/100 WY (95% CI: 0.4-0.5) and in the USA 1.9 events/100 WY (95% CI: 1.7-2.1). Differences in compliance (1.3 pregnancies/100 WY) accounted for 90% of the geographical difference seen between Europe and the USA. DNG/EV showed lower contraceptive failure rates compared to the comparators; 0.9% DNG/EV, 2.1% oCOC and 2.8% LNG after 4 years. Overall, 1167 (2.3%) of women stopped contraceptive use with the intention of becoming pregnant with 89% conceiving within 2 years. No significant differences were seen between groups after adjusting for age.

CONCLUSION/DISCUSSION

DNG/EV is associated with similar contraceptive effectiveness in typical-use settings when compared to oCOC and LNG. There was no difference observed between cohorts in fertility following OC use.

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.

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.

Impact of obesity on the pharmacokinetics of levonorgestrel-based emergency contraception: single and double dosing

OBJECTIVE

To determine if differences exist in the pharmacokinetics (PK) of levonorgestrel-based emergency contraception (LNG-EC) in obese and normal body mass index (BMI) users and test whether doubling the dose of LNG-EC in obese women increases total and free (active) LNG serum concentrations.

STUDY DESIGN

Healthy, reproductive-age women with obese and normal BMIs received 1.5mg LNG orally (ECx1) and then in a subsequent menstrual cycle, the obese group also received 3mg LNG (ECx2). Dosing occurred during the follicular phase. Total and free LNG PK parameters were obtained via serum samples through an indwelling catheter at 0, 0.5, 1, 1.5, 2, and 2.5h. The primary outcome was the difference in total and free LNG concentration maximum (Cmax) between ECx1 and ECx2 in the obese group.

RESULTS

A total of 10 women enrolled and completed the study (normal BMI=5, median 22.8kg/m(2), range 20.8-23.7; obese BMI=5, 39.5kg/m(2), range 35.9-46.7). The total LNG Cmax for obese subjects following ECx1 (5.57±2.48ng/mL) was significantly lower than the level observed in normal BMI women (10.30±2.47, p=.027). Notably, ECx2 increased the Cmax significantly (10.52±2.76, p=.002); approximating the level in normal BMI subjects receiving ECx1. Free LNG Cmax followed a similar pattern.

CONCLUSION

Obesity adversely impacts both the total and free Cmax levels of LNG EC and this likely explains its lack of efficacy in obese women. Doubling the dose appears to correct the obesity-related PK changes but additional research is needed to determine if this also improves EC effectiveness in obese women.

IMPLICATIONS

This study demonstrates that obesity interferes with the pharmacokinetics of LNG EC, and that doubling the dose may be an effective strategy to improve its efficacy in obese women.

A case-control analysis of oral contraceptive use and breast cancer subtypes in the African American Breast Cancer Epidemiology and Risk Consortium

Introduction

Recent oral contraceptive (OC) use has been consistently associated with increased risk of breast cancer, but evidence on specific breast cancer subtypes is sparse.

Methods

We investigated recency and duration of OC use in relation to molecular subtypes of breast cancer in a pooled analysis of data from the African American Breast Cancer Epidemiology and Risk Consortium. The study included 1,848 women with estrogen receptor-positive (ER+) breast cancer, 1,043 with ER-negative (ER-) breast cancer (including 494 triple negative (TN) tumors, which do not have receptors for estrogen, progesterone, and human epidermal growth factor 2), and 10,044 controls. Multivariable polytomous logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for exposure categories relative to never use, controlling for potential confounding variables.

Results

OC use within the previous 5 years was associated with increased risk of ER+ (OR 1.46, 95% CI 1.18 to 1.81), ER- (OR 1.57, 95% CI 1.22 to 1.43), and TN (OR 1.78, 95% CI 1.25 to 2.53) breast cancer. The risk declined after cessation of use but was apparent for ER+ cancer for 15 to 19 years after cessation and for ER- breast cancer for an even longer interval after cessation. Long duration of use was also associated with increased risk of each subtype, particularly ER-.

Conclusions

Our results suggest that OC use, particularly recent use of long duration, is associated with an increased risk of ER+, ER-, and TN breast cancer in African American women. Research into mechanisms that explain these findings, especially the association with ER- breast cancer, is needed.

Self-reported and verified compliance in a phase 3 clinical trial of a novel low-dose contraceptive patch and pill

OBJECTIVE

Pregnancy rates in US contraceptive clinical trials are increasing due to decreased treatment compliance. This study compared compliance with a new low-dose levonorgestrel (LNG) and ethinyl estradiol (EE) contraceptive patch (CP, Twirla™) with that of a low-dose combination oral contraceptive (COC) in a demographically diverse population.

STUDY DESIGN

This analysis was part of an open-label, parallel-group, multicenter phase 3 study that randomized healthy sexually active women (17-40years) to 13cycles of LNG/EE CP or 6cycles of COC, then 7cycles of LNG/EE CP. We defined self-reported compliance as cycles that, according to diaries, show 21days of patch wear without missed days or any patch worn >7days or 21days of pill-taking without missed pill days. We verified compliance by detectable plasma presence of LNG and EE at cycles 2, 6, and 13.

RESULTS

Of the intention-to-treat population with diary information (N=1328, mean age 26.4years, 46% minorities, 33% obese), 10.0% of the CP (n=998) versus 21.2% of the COC group (n=330) self-reported noncompliance after 6cycles (p<.001). Laboratory assessments verified 10-14% of participants in both groups as noncompliant. Self-reported perfect use did not vary between obese [body mass index (BMI) ≥30kg/m(2)] versus nonobese (BMI <30kg/m(2)) participants in both groups or when stratified by age, education, or race/ethnicity in the CP group.

CONCLUSIONS

Self-reported compliance was significantly greater in the CP than COC group and did not vary by obesity status. Discrepancies between self-reported and verified compliance question reliability of patient diaries.

IMPLICATIONS STATEMENT

This paper, based on an analysis of a phase 3 trial, shows that compliance was significantly greater with a new weekly transdermal CP than with a once-daily COC in obese as well as nonobese participants. Discrepancies between self-reported compliance and laboratory-verified compliance raise questions regarding the reliability of patient diaries.

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.

Increased exposure of norethindrone in HIV+ women treated with ritonavir-boosted atazanavir therapy

OBJECTIVE

Pharmacokinetics of norethindrone in combination oral contraceptive regimen are well described among HIV+ women treated with ritonavir-boosted protease inhibitor therapies; however, such characterization is lacking in women using progestin-only contraception. Our objective is to characterize pharmacokinetics of norethindrone in HIV+ women using ritonavir-boosted atazanavir treatment during progestin-only contraceptive regimens.

STUDY DESIGN

An open-label, prospective, nonrandomized trial to characterize the pharmacokinetics of norethindrone in HIV+ women receiving ritonavir-boosted atazanavir (n=10; treatment group) and other antiretroviral therapy known to not alter norethindrone levels (n=17; control group) was conducted. Following informed consent, women were instructed to take a single daily fixed oral dose of 0.35 mg norethindrone and 300 mg/100 mg atazanavir/ritonavir for 22 days. On day 22, serial blood samples were collected by venous catheter at 0, 1, 2, 3, 4, 6, 8, 12, 24, 48 and 72 h. Whole blood was processed to collect serum and stored at -20°C until later analysis using radioimmunoassay. Pharmacokinetic parameters were estimated using noncompartmental method.

RESULTS

In the treatment group, compared to the control group, an increase in area under the curve₀₋₂₄ (16.69 h*ng/mL vs. 25.20 h*ng/mL; p<.05) and maximum serum concentration (2.09 ng/mL vs. 3.19 ng/mL; p<.05), decrease (25%-40%) in apparent volume of distribution and apparent clearance, and unaltered half-life were observed.

CONCLUSION(S)

Our findings suggest that progestin-only contraceptives, unlike combination oral contraceptives, benefit from drug-drug interaction and achieve higher levels of exposure. Further studies are needed to establish whether pharmacokinetic interaction leads to favorable clinical outcomes.

IMPLICATIONS

Norethindrone-based progestin-only contraceptives, unlike combination oral contraceptives, exhibit greater drug exposure when co-administered with ritonavir-boosted atazanavir regimen and thus may not warrant a category 3 designation by the World Health Organization. Prospective studies are needed to confirm whether pharmacokinetic interaction results in favorable clinical outcomes.

Correcting oral contraceptive pharmacokinetic alterations due to obesity: a randomized controlled trial

OBJECTIVE

To determine if increasing the hormone dose or eliminating the hormone-free interval improves key pharmacokinetic (PK) alterations caused by obesity during oral contraceptive (OC) use.

STUDY DESIGN

Obese [body mass index (BMI)≥30 kg/m(2)], ovulatory, otherwise healthy, women received an OC containing 20 mcg ethinyl estradiol (EE)/100 mcg levonorgestrel (LNG) dosed cyclically (21 days active pills with 7-day placebo week) for two cycles and then were randomized for two additional cycles to the following: continuous cycling (CC, a dose neutral arm using the same OC with no hormone-free interval) or increased dose (ID, a dose escalation arm using an OC containing 30 mcg EE/150 mcg LNG cyclically). During Cycles 2, 3 and 4, outpatient visits were performed to assess maximum serum concentration (Cmax), area under the curve (AUC0-∞) and time to steady state as well as pharmacodynamics. These key PK parameters were calculated and compared within groups between baseline and treatment cycles.

RESULTS

A total of 31 women enrolled and completed the study (CC group, n=16; ID group, n=15). Demographics were similar between groups [mean BMI: CC, 38 kg/m(2) (S.D. 5.1); ID, 41 kg/m(2) (S.D. 7.6)]. At baseline, the key LNG PK parameters were no different between groups; average time to reach steady state was 12 days in both groups; Cmax were CC: 3.82±1.28 ng/mL and ID: 3.13±0.87 ng/mL; and AUC0-∞ were CC: 267±115 h ng/mL and ID: 199±75 h ng/mL. Following randomization, the CC group maintained steady-state serum levels whereas the ID group had a significantly higher Cmax (p<.001) but again required 12 days to achieve steady state. However, AUC was not significantly different between CC (412±255 h ng/mL) and ID (283±130 h ng/mL). Forty-five percent (14/31) of the study population had evidence of an active follicle-like structure prior to randomization and afterwards this decreased to 9% (3/31).

CONCLUSION

Both increasing the OC dose and continuous dosing appear to counteract the impact of obesity on key OC PK parameters.

IMPLICATIONS

Obesity adversely affects the pharmacokinetics of very low dose OC pills. Although the impact of these changes on OC efficacy is still under debate, PK parameters can be normalized in obese users by continuous dosing or increasing to a low-dose pill.

Impact of body mass index on suppression of follicular development and ovulation using a transdermal patch containing 0.55-mg ethinyl estradiol/2.1-mg gestodene: a multicenter, open-label, uncontrolled study over three treatment cycles

BACKGROUND

Body mass index (BMI) may influence ovulation inhibition resulting from transdermal hormone delivery. Investigation of this effect is important given the high prevalence of obesity in the US.

STUDY DESIGN

This open-label, uncontrolled, Phase 2b trial stratified 173 women (18-35 years) according to three BMI groups (Group 1, n = 56, ≤ 30 kg/m²; Group 2, n = 55, > 30 kg/m² and ≤ 35 kg/m²; and Group 3, n = 47, > 35 kg/m²). Women used a contraceptive patch containing 0.55-mg ethinyl estradiol (EE) and 2.1-mg gestodene (GSD). The EE/GSD patch was used weekly for three 28-day cycles (one patch per week for 3 consecutive weeks followed by a 7-day, patch-free interval), and its effect on ovulation was assessed by the Hoogland score, a composite score that comprises transvaginal ultrasound and estradiol (E₂) and progesterone levels every 3 days in Cycles 2 and 3. Evaluation of pharmacokinetic parameters was a secondary aim of the study, and blood samples for analytic determination of EE, GSD and sex hormone-binding globulin were taken during the pretreatment cycle, Cycle 2 and Cycle 3. Compliance was assessed using diary information and serum drug levels.

RESULTS

In the per-protocol set, there were only six ovulations during the study, and no participant ovulated in both study cycles. One ovulation occurred in Group 1, three in Group 2 and two in Group 3. Ovulation inhibition was unaffected by BMI; in all groups, most participants had Hoogland scores of 1 or 2 (i.e., follicle-like structures < 13 mm: Group 1, ≤ 30 kg/m², 80.0% in Cycle 2, 85.7% in Cycle 3; Group 2, > 30 kg/m² and ≤ 35 kg/m², 61.4% in Cycle 2, 75.0% in Cycle 3; Group 3, > 35 kg/m², 78.0% in Cycle 2, 72.5% in Cycle 3). Serum levels of follicle-stimulating hormone, luteinizing hormone, E2 and progesterone were similar between groups. Body weight had a limited effect on EE clearance that was unlikely to be clinically relevant.

CONCLUSION

The EE/GSD patch provided effective ovulation inhibition, even in women with higher BMI.

IMPLICATIONS

This is the largest-to-date study of physiologic endpoints and found no clinically important differences in ovarian suppression among obese and normal-weight users of the EE/GSD contraceptive patch, thus providing reassurance that obese women can achieve the same high level of contraceptive protection as normal-weight users.

An ethinyl estradiol-levonorgestrel containing oral contraceptive does not alter cytochrome P4502C9 in vivo activity

Oral contraceptives have been in wide use for more than 50 years. Levonorgestrel, a commonly employed progestin component of combined oral contraceptives, was implicated in drug-drug interactions mediated via CYP2C9. Although in vitro studies refuted this interaction, there are no confirmatory in vivo studies. In the current study, we examined the phenotypic status of CYP2C9 using low-dose (125 mg) tolbutamide before and after oral contraceptive use in reproductive age women. Blood was collected 24 hours after the tolbutamide oral dose was administered, plasma was isolated, and tolbutamide concentration (C24) was measured using liquid chromatography-mass spectrometry. The natural logarithm of tolbutamide C24, a metric for CYP2C9 phenotype, was found to be equivalent (within 80%-125% equivalency boundaries) before and after oral contraceptive use. In conclusion, levonorgestrel-containing oral contraceptives, the most commonly used form of oral contraception, do not affect the status of the CYP2C9 enzyme. This suggests that it is safe to co-administer levonorgestrel-containing oral contraceptives and CYP2C9 substrates, which include a wide array of drugs.