Long-term birth control options such as intrauterine devices (IUDs) and under-the-skin implants may be 20 times more effective in preventing pregnancy than short-term contraceptives, such as birth control pills, patches and rings. A study published May 2012 in the New England Journal of Medicine was one of the largest ever done in the United States to compare birth control failure rates over a three-year period.
Birth control pills are the most commonly used, reversible contraceptive in the United States, but their effectiveness depends on women remembering to take a daily pill and having easy access to refills.
Patches and rings require less attentiveness than pills, but they still leave room for human error. The patch needs to be changed weekly, while the ring needs to be changed every month.
In contrast, IUDs and implants are designed to be foolproof.
IUDs are T-shaped pieces of plastic which are inserted into the uterus by a gynecologist, and can remain in place for 5-10 years.
Implants are matchstick-size devices which are inserted below the skin on the upper arm that release a slow trickle of hormones, and can last up to three years.
Many women, however, cannot afford the up-front costs of these methods, which can be more than $500.
For this study, investigators wanted to determine whether or not educating women about the effectiveness of various birth- control options and having them choose a method without considering cost would reduce the rate of unplanned pregnancy. Free birth control was provided to the participants.
Researchers tracked nearly 7,500 sexually active women in the St. Louis area, ages 14-45, who were considered at risk for an unplanned pregnancy. The women also received counseling about each method's risks, benefits and effectiveness.
Participants could choose among the following birth control methods: IUD, implant, birth control pills, patch, ring and contraceptive injection.
The largest group, nearly 5,800, chose IUDs or implants. Slightly more than 1,500 women selected pills, patches or vaginal rings, and the smallest group, 176 women, chose a contraceptive injection.