Advances in female hormonal contraception: current alternatives to oral regimens.
Despite the wide variety of reversible contraceptives, unintended pregnancy rates in developed nations are still considered markedly elevated by most epidemiologists and clinicians. Indeed, the US has one of the highest unintended pregnancy rates among the industrialized nations of the world. Although many factors appear to influence this problem, what may play an important role in this apparent paradox is the process by which a woman obtains contraception. Although most nonbarrier methods have similar efficacy, the ability to use that method consistently and correctly will determine whether it provides maximal contraception. Oral contraceptives are the most popular method in the US; accordingly, the process by which US women obtain their contraception may not take into account the desire of many women to use nondaily methods. The recent introduction of nondaily methods in the US and elsewhere has provided more choice so that a successful contraceptive decision can be made in the first instance rather than after an adverse clinical outcome or unintended pregnancy with a method not as well suited to that woman's lifestyle. These new methods are not characterized by improved safety or efficacy; rather, they have novel components or delivery systems that may provide important options to women who may not be able to or willing to use existing methods of contraception. The transdermal patch, vaginal ring, and monthly injectable are combination estrogen/progestogen methods characterized by novel delivery systems and compliance regimens. The single rod implant is a facile and well accepted method that has not yet been approved for use in the US but has been an increasingly popular choice elsewhere. The levonorgestrel intrauterine system has been used in Europe for over 10 years and has recently been introduced in the US. This intrauterine contraceptive provides high efficacy and reliability, and may have considerable noncontraceptive benefit with regard to the nonsurgical treatment of uterine bleeding problems and endometrial protection for menopausal hormone therapy. The increasing popularity of these methods can be considered a testament to the desire of women to consider nondaily contraceptives as first-line, mainstream options. It is hoped that increasing use of these methods will lead to a considerable decrease in the rate of unintended pregnancy.