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Despite improvements in contraceptive technology and a growing market of effective and safe contraceptive options, unintended pregnancy continues to be a significant public health issue in the United States. The more than 2.5 million unintended pregnancies in the United States each year make up nearly half (49%) of all pregnancies. During their reproductive years, 48% of women will have an unintended pregnancy. Adolescents and women in poverty are at highest risk of having an unplanned birth (), an event that may further challenge their ability to obtain an education, appropriate job training, and a meaningful job.

Because of social, political, financial, or legal reasons, many contraceptive methods have been removed from the contraceptive armamentarium, sometimes almost as quickly as they were introduced. The original subdermal implant, a monthly intramuscular injection containing medroxyprogesterone acetate and estradiol cypionate, and a multitude of intrauterine devices have all been withdrawn from the US market after facing insurmountable problems. Over the last 45 years, however, oral contraceptives (OCs) have undergone extensive study, continual development and significant improvements. Unlike the original OCs, new low-dose OCs, as shown in Fig. 1, have few health risks when used in properly selected users and many health benefits. Currently, more than 100 million women worldwide and 18 million women in the United States rely on OCs ().

Concerns regarding the estrogen-related adverse effects with use of combination oral contraceptives (OCs) have led to a progressive reduction in the estrogen dose since their introduction in the 1960s. Prompting these concerns were the numerous epidemiological studies linking estrogen in OCs to breast cancer () and cardiovascular complications, including an increase in thromboembolic events and myocardial infarction (). By the early 1990s, low-dose OCs containing 20–35 μg of ethinyl estradiol (EE) were the most commonly used formulations, and products with more than 50 μg of EE were no longer being marketed. Epidemiological studies reported improved safety profiles of these lower dose formulations (–) (Fig. 1).

Progestin-only pills (POPs) are often referred to as mini-pills. POPs contain about 35–75% of the progestin dose contained in combination oral contraceptives (OCs) but they are taken continuously without a pill-free interval. Their effectiveness is generally similar to combination OCs. It is critical that POPs be taken at the same time every day; failure to do this may explain the higher typical-use failure rates reported in some studies. They are associated with more breakthrough spotting and bleeding but fewer serious side effects. Although not as well-studied as combination OCs, POPs are thought to have many of the same non-contraceptive health benefits.

After its introduction in 2002, the transdermal contraceptive patch became one of the fastest growing birth control options in the United States (Fig. 1). Like combination oral contraceptives (OCs), the contraceptive patch is effective and rapidly reversible. The patch was designed to mimic the hormonal action of a 35-μg OC and carries many of the same advantages and disadvantages. It is expected that the patch will have many of the same contraceptive and non-contraceptive benefits associated with OCs. The biggest advantage of the patch is its once-a-week administration. The most common side effects are application site reaction, breast discomfort, nausea, and headaches (). Recently, the package insert has been changed to include a statement that patch users are exposed to about 60% more estrogen than those using a typical oral contraceptive pill containing estrogen.

In development for more than 20 years, the first vaginal ring contraceptive (NuvaRing®) was approved by the Food and Drug Administration in 2001 and marketed in 2002. Like oral contraceptive (OC) pills, the ring is safe, effective, and rapidly reversible (). It offers the lowest estrogen dose of any estrogenprogestin contraceptive product marketed in the United States. It is worn for 21 days then removed and discarded. Bleeding ensues and 7 days later a new ring is inserted to start the next cycle. The advantages and side effects are similar to OCs. Ring users are expected to experience similar non-contraceptive health benefits as pill users. The biggest advantage of ring use is its once-a-month insertion and removal. Ring users do not have the burden of taking a pill every day and yet they retain complete control of initiating and discontinuing use of the method.

Depo-Provera® (depot medroxyprogesterone acetate [DMPA]) is an extremely effective contraceptive agent. Since its introduction into the market in the 1960s, DMPA has been used for a variety of gynecological conditions including endometriosis and abnormal menstrual bleeding. For many years, DMPA was also commonly used “off-label“ as a contraceptive agent, especially in women who were not candidates for oral contraceptive (OC) pills. In 1992, the Food and Drug Administration (FDA) approved the marketing of DMPA as a contraceptive agent.

Subdermal contraceptive implants offer women long-acting, controlled release of progestins. Over the past 20 years, they have been approved in more than 60 countries and used by more than 11 million women worldwide. Their high efficacy along with ease of use make them a good contraceptive option for women who require progestin-only methods because they should not use estrogen, teens who find adherence to a contraceptive regime difficult, as well as healthy adult women who desire long-term protection (). Norplant®, no longer marketed in the United States, garnered 1 million American users but was difficult to insert and remove (, ). Now, a highly effective and long-lasting singlerod etonogestrel subdermal implant (Implanon®) will make implant contraception available again in the United States.

Women in the United States currently may choose between two forms of intrauterine contraception (IUC): the 380 mm 2 copper T intrauterine device (IUD) (TCu380A, marketed as ParaGard ®) and the levonorgestrel intrauterine system (LNG-IUS, sold as Mirena ®) (Fig. 1). Both devices offer excellent, reversible, long-term contraception, but each manifests a unique profile of benefits and side effects. Generally speaking, women using the copper IUD maintain their men-strual cycles, but are more likely to experience menorrhagia. With the LNG-IUS, endometrial suppression results in an alteration of bleeding patterns and 20% of users become amenorrheic within 1 year of use and the majority of users become amenorrheic by 5 years (, ).

Male condoms are a popular contraceptive method. Additionally, they also play an integral role in US public health programs designed to prevent the spread of HIV and other sexually transmitted infections (STIs). Since the 1986 report from the US Surgeon General advocating the use of condoms to help prevent the spread of AIDS, awareness of the benefits of condom use has continued to increase. The percentage of reproductive-age women choosing condoms for contraceptive protection increased from 13% in 1988 to around 20% today. Use among sexually active adolescents is dependent on a variety of factors, including race and ethnicity, but averages around 45% (, ).