Worldwide, almost half of all pregnancies are unintended—many of which can be attributed to unmet need for contraception, method dissatisfaction, or inconsistent contraceptive use. Among women with an unmet need for contraception, women with a body mass index greater than or equal to 30 are more likely to report that they are not using any method of contraception.
Reducing unmet need and improving method satisfaction among women with a higher BMI, who account for 15 percent of all adult women globally, is critical to reducing adverse maternal and child health outcomes as women who fall under this category are at significantly higher risk of pregnancy-related complications.
Many currently available hormonal contraceptive options are made with ethinyl estradiol, a synthetic estrogen that has been associated with an increased risk of a venous thromboembolism (VTE). The risk of VTE for women with a higher BMI using a method based on ethinyl estradiol is five to eight times that of women with a higher BMI not using a method made with the synthetic estrogen. However, this risk is still lower than that associated with unintended pregnancy and the postpartum period. It is critical to expand the range of contraceptive options that are safe for all individuals.
Researchers at the Population Council have developed a three-month contraceptive vaginal ring that delivers a daily dose of Nestorone®, a progesterone derivative, and estradiol. Estradiol is a physiological estrogen and is not associated with increased VTE risk. Given the potentially improved safety profile, the vaginal ring is being evaluated for use by women with a BMI up to 35. A Phase 2b study is currently underway to evaluate safety and efficacy. The study is conducted by the NICHD Contraceptive Clinical Trials network in 11 clinical trial sites in the United States. We expect that the new vaginal ring will be a highly effective, easy-to-use contraceptive method.
A new user-controlled vaginal ring that is safe for women with a high body mass index expands options and may increase method acceptability. The Nestorone® estradiol vaginal ring is likely to be one of the first non-oral contraceptives on the market to deliver hormones that are structurally similar to natural estradiol and progesterone. In addition, the product addresses concerns related to disposal of ethinyl estradiol and is expected to have a lower environmental impact.