Contraceptive Efficacy: IUDs and Implants vs. Contraceptive Pills, Patches, and Vaginal Rings

In May, the New England Journal of Medicine published an article called "Effectiveness of Long-Acting Reversible Contraception,"1 which showed that long-acting, but reversible contraception, including intrauterine devices and implants, were better at preventing unintended pregnancies than shorter-term options, such as contraceptive pills, transdermal patches or vaginal rings. The failure rate for the short-term contraception was 4.5 per 100 participant year compared to 0.27 among the long-term contraception group.

Below Aparna Sridhar, MD, a clinical fellow in the Department of Obstetrics and Gynecology Division of Family Planning at the University of California, Los Angeles, discusses the study and strategies for physicians working with patients to choose contraception.

 

LONG-TERM VS. SHORT-TERM

A recent study by researchers at the Washington School of Medicine found that longer-lasting contraception choices, such as the IUD and hormone injections, did a better job of preventing pregnancy than the pill and other short-term contraceptive methods. What should physicians take from this study when making prescribing decisions?

Women have a variety of contraceptives to choose from at this point in time. Selecting a birth control method is an important decision in their lives. The contraceptive choices include both short-term and longer-acting options. This study arms physicians with strong evidence-based information about which types of birth control methods are more effective in preventing pregnancies over time and reinforces the efficacy of long-acting reversible contraceptive methods. Results of the study highlight the fact that contraceptive failure rates of long-acting reversible methods (0.27 per 100 participant years) are significantly lower compared to the pills, patch and ring (4.55 per 100 participant years). The results were particularly striking for women younger than 21 years of age, emphasizing the potential benefits of intrauterine devices (IUDs) and implants in this high-risk age group. IUDs are thus one of the preferred methods for young adults, contrary to the prevalent misconception that younger nulliparous woman should not be using them.

Any time a physician outlines contraception options to a patient, he or she should first be certain to speak with patients about their reproductive life goals and plans. It is a good idea to suggest the patient thinks about if, and when, she would like to get pregnant. Until then, physicians should encourage patients to choose a method suitable to their lifestyle. If the patient does not want to get pregnant in the next few years, long-acting reversible birth control methods such as IUDs and implants should be strongly encouraged. Short-term methods are appropriate if the patients are considering pregnancy in the next few months.

Are there patients who should not use longer-term contraceptive methods due to potential risks or consequences?

Not really. IUDs and implants are usually well tolerated by the majority of women. Placement of an IUD is not recommended if a woman has active infection of the uterus or cervix. Another rare example might be not recommending a hormonal IUD or implant to a patient who has breast cancer. Some women might also not be able to use an IUD if they have congenital anomalies of the uterus, which would make an IUD difficult to place.

A good resource for physicians looking at this issue is the Centers for Disease Control and Prevention guidelines2, U.S. Medical Eligibility Criteria for Contraceptive Use, 2010. This document, endorsed by the American Congress of Obstetrics and Gynecology, is a comprehensive guide to contraception, which can help providers understand the benefits and risks of using various contraceptive methods in patients with certain health conditions. Providers should take advantage of this resource to find appropriate birth control options for medically complicated patients.