The emerging role of obesity in short-acting hormonal contraceptive effectiveness

Variability in Contraceptive Clinical Trial Design and the Challenges in Making Comparisons Across Trials

Clinical trials of contraceptives have often differed in their study designs, making cross-trial comparisons difficult. This brief report outlines some of the technical design features that can vary from trial to trial. For example, the overall number of menstrual cycles in a study has substantial impact on the final efficacy determination; however, the rules related to qualifying cycles can differ based on the length of the study and the statistical analysis plan. In two commonly used methods of calculating efficacy, the Pearl Index and the time-to-event analysis, inclusion of fewer menstrual cycles results in higher calculated failure rates. Statistical analysis plans for contraceptive trials have sometimes excluded menstrual cycles because of an absence of documented vaginal intercourse and the concomitant use of another birth control method. Other design features that have varied between contraceptive trials relate to body mass index inclusion/exclusion criteria and the definition of "on-treatment" pregnancy. In addition, study designs of non-hormonal products can differ from those of hormonal products in their length and rules for qualifying cycles. The Draft Guidance for Hormonal Contraception, published in 2019 by the US Food and Drug Administration (FDA), will hopefully lead to more uniform trial design in the future, particularly for hormonal products. In the meantime, health care providers and patients should be aware of the nuances in trial design that make direct comparisons about relative efficacy challenging.

Advances in contraception research and development

PURPOSE OF REVIEW

In the past few years, there have been great advances in contraceptive technology and development. Here we review advances in contraception over the past two years including new medications, and technologies.

RECENT FINDINGS

Contraception must be discussed within the context of individual goals and context. New contraceptive options approved by the FDA in the past two years include a year-long vaginal ring, a progestin-only pill that is as effective as combined oral contraceptive pills, a new hormonal patch and a vaginal gel that may also help prevent sexually transmitted infections.There are still areas of contraceptive research that are very much unknown including biomarkers of contraceptive efficacy or side effects, how individuals or groups metabolize contraception, initiation around reproductive life events or the discontinuation of other methods.

SUMMARY

There have been many new contraceptives developed over the past few years to address challenges of existing contraception and create new methods; yet, there remain many unanswered questions in contraceptive research. Contraceptive technology has far-reaching consequences, and independent of technology itself, represents a great opportunity for truly personalized medicine.

Contraception for Adolescents

Although pregnancy and abortion rates have declined in adolescents, unintended pregnancies remain unacceptably high in this age group. The use of highly effective methods of contraception is one of the pillars of unintended pregnancy prevention and requires a shared decision making process within a rights based framework. Adolescents are eligible to use any method of contraception and long-acting reversible contraceptives, which are “forgettable” and highly effective, may be particularly suited for many adolescents. Contraceptive methods may have additional non-contraceptive benefits that address other needs or concerns of the adolescent. Dual method use should be encouraged among adolescents for the prevention of both unintended pregnancies and sexually transmitted infections. Health care providers have an important role to play in ensuring that adolescents have access to high quality and non-judgmental reproductive health care services and contraceptive methods in adolescent-friendly settings that recognize the unique biopsychosocial needs of the adolescent.

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.

Ulipristal acetate compared to levonorgestrel emergency contraception among current oral contraceptive users: a cost-effectiveness analysis

OBJECTIVE

To estimate the cost-effectiveness of ulipristal acetate (UPA) and levonorgestrel (LNG) emergency contraception (EC) on pregnancy prevention among combined oral contraceptive (COC) pill users with an extended pill-free interval. We accounted for the potential interaction of COCs and obesity on EC efficacy.

METHODS

We built a decision-analytic model using TreeAge software to evaluate the optimal oral EC strategy in a hypothetical cohort of 100,000 twenty-five-year-old women midcycle with a prolonged "missed" pill episode (8-14 days). We used a 5-year time horizon and 3% discount rate. From a healthcare perspective, we obtained probabilities, utilities and costs inflated to 2018 dollars from the literature. We set the threshold for cost-effectiveness at a standard $100,000 per quality-adjusted life-year. We included the following clinical outcomes: number of protected cycles, unintended pregnancies, abortions, deliveries and costs.

RESULTS

We found that UPA was the optimal method of oral EC, as it resulted in 720 fewer unintended pregnancies, 736 fewer abortions and 80 fewer deliveries at a total cost savings of $50,323 and 79 additional adjusted life-years. UPA continued to be the optimal strategy even in the case of obesity or COCs impacting UPA efficacy, in which a COC interaction would have to change efficacy of UPA by 160% before LNG was the dominant strategy.

CONCLUSION

Our models found that UPA was the dominant choice of oral EC among COC users with a prolonged "missed" pill episode, regardless of body mass index or an adverse interaction of COCs on UPA.

IMPLICATIONS

Ulipristal acetate is the dominant choice of oral emergency contraception among combined oral contraceptive users.