By Irina Yacobson, MD and Markus Steiner, PhD
Contraceptive implants are matchstick-sized rods that contain a progestin hormone. Surgically implanted beneath the skin of a woman's upper arm, the implants provide contraception as the progestin is slowly released over 3 to 5 years.1 Contraceptive implants have been approved in more than 60 countries and are currently being used by millions of women around the world.2
How Implants Work
Implants prevent pregnancy by thickening cervical mucus (mechanically preventing the sperm from reaching the egg) and through hormonal effects that prevent ovulation in about half of menstrual cycles.3
Insertion of the implant requires a minor surgical procedure by a trained practitioner using appropriate aseptic techniques in a sterile surgical environment. The procedure usually takes just a few minutes and does not require stitches. After surgical insertion, implants do not require any action on the woman's part. The small rods are not biodegradable and should be removed when they are no longer active or when contraception is no longer desired.
Implant Types
In 1983, Norplant became the first commercially available implant. Consisting of six hormone-releasing rods, Norplant has been recently replaced by simpler systems. The new products -- Implanon, Jadelle, and Sino-Implant (II) -- are just as effective as Norplant, but they are easier to insert and remove because they consist of only one or two rods. Sino-Implant (II) is being introduced at lower cost in parts of the developing world.
- Implanon: 1 rod, provides contraception for 3 years, contains etonogestrel
- Jadelle: 2 rods, provides contraception for 5 years, contains levonorgestrel
- Sino-Implant (II): 2 rods, provides contraception for 4 years, contains levonorgestrel
- Norplant: 6 rods, provides contraception for 5-7 years (discontinued in 2008)
Effectiveness
Contraceptive implants are just as effective as sterilization, except that the implant's effects are completely reversible after the rods are removed.4 Although Sino-implant (II) is currently approved for four years, clinical studies indicate that it may be effective for at least five years.
Side Effects
As with other hormonal contraceptive methods, some women experience changes in their menstrual bleeding patterns, including irregular, lighter bleeding or the absence of bleeding. Other side effects include headaches, breast tenderness, mood changes, and nausea -- some of which might decrease over time.
Health Benefits
Unlike some other hormonal forms of contraception, implants do not contain estrogen, so women can safely breastfeed with an implant in place. Because implants may cause menstrual bleeding to be lighter, less frequent, or absent, some users may have a decreased risk of iron-deficiency anemia. Users also gain protection against health risks associated with pregnancy, pelvic inflammatory disease, and ectopic pregnancy. Implants have no effect on sexual function.
Who Can Use Implants?
In most cases, women with the following conditions should use a different form of contraception:
- Serious liver disease, such as most liver tumors or severe cirrhosis
- Current deep venous thrombosis or pulmonary embolus
- Unexplained or unusual vaginal bleeding that requires evaluation
- Breast cancer (currently or in the past)
- Rheumatic disease, such as systemic lupus erythematosus (unless the woman is on immunosuppressive treatment)
In most cases, breastfeeding women who want to use a contraceptive implant should wait until they are six weeks postpartum to have the implant inserted.
Unlike some other hormonal forms of contraception, implants can be used by cigarette smokers, women who have risk factors for cardiovascular disease (including high blood pressure), and women who are breastfeeding (after 6 weeks postpartum).
Disease Prevention
Implants provide no protection against sexually transmitted infections (STIs) and HIV/AIDS. A barrier method, such as a male or female condom, should be used to decrease the risk of acquiring HIV and other STIs. Women with HIV/AIDS can use implants, but they should also use a barrier method to decrease the risk of transmitting the virus to their partners.
References
- Raymond EG. 2007. "Contraceptive Implants." In Contraceptive Technology, ed. RA Hatcher et al., pp 145-156, New York: Ardent Media.
- Bongaarts J and Johansson E. Future Trends in Contraception in the Developing World: Prevalence and Method Mix. Policy Research Division Working Papers No. 141. Population Council: New York.
- Van den Bosch T, Donders GG, Riphagen I, et al. Ultrasonographic features of the endometrium and the ovaries in women on etonogestrel implant. Ultrasound Obstet Gynecol 2002;20:377-380.
- Steiner MJ. Contraceptive effectiveness: what should the counseling message be? JAMA 1999;282:1405-1407.
External Links
Last updated: 2009
