Counsel on efficacy of contraceptive implant
Clinician office phones might be ringing following news reports of women in the United Kingdom (UK) who experienced unintended pregnancies while using the contraceptive implant Implanon. How do you counsel women on this form of long-acting contraception?
Several women in the UK have taken legal action after they received the contraceptive implant and became pregnant. According to the UK Department of Health, 584 official reports of pregnancies among implant users have been recorded in the UK since the device was introduced in 1999. About 1.4 million UK women have used Implanon; at present, 800,000 women are estimated to be relying on the device for contraception.1
It is important to put the some 600 pregnancies into perspective, says Anita Nelson, MD, professor in the Obstetrics and Gynecology Department at the David Geffen School of Medicine at the University of California in Los Angeles. Implanon has the highest efficacy among available contraceptive methods.2 In an overview of the clinical data, zero pregnancies were recorded during 53,530 cycles (4,103 woman-years), resulting in a Pearl index of 0.0 (95% confidence interval, 0.00-0.09).2
Implanon is a highly effective method of birth control, states Abbey Berenson, MD, MMS, professor in the Department of Obstetrics and Gynecology and director of the Center for Interdisciplinary Research in Women's Health, both at University of Texas Medical Branch in Galveston. Its advantage lies in that it does not require the patient to remember to take a pill every day or come in to the clinic and get a shot every three months, she notes. Thus, the actual pregnancy rate is much lower with Implanon than most other contraceptive methods, Berenson states.
Check for insertion
There have been reports of problems with inserting and removing Implanon, according to the UK Department of Health.1 In some women who experienced an unintended pregnancy, Implanon was found not to have been inserted, the department states. These issues have been kept under close review by the agency.1
All healthcare providers must receive training before inserting or removing Implanon, according to the package insert. Prior to inserting the device, instructions call for the clinician to carefully remove the Implanon applicator from its blister pack, keep the shield on the needle, and look for the Implanon rod, seen as a white cylinder, inside the needle tip. If the Implanon rod is not visible, the clinician should tap the top of the needle shield against a firm surface to bring the implant into the needle tip.
Following visual confirmation, instructions state to lower the Implanon rod back into the needle by tapping it back into the needle tip, then remove the needle shield while holding the applicator upright. Because Implanon can fall out of the needle, clinicians should keep the applicator in the upright position after the needle shield is removed until the moment of insertion.3
Confirm that Implanon has been inserted by inspecting the needle tip for the absence of the Implanon rod and the visualization of the grooved obturator tip. Palpate the arm to check for the implant, and have the patient to do so as well.
New device under review
Insertion errors might be diminished with Nexplanon, an advanced generation of Implanon. Introduced in the UK in October 2010, Nexplanon contains the same amount of etonogestrel (68 mg) and is bioequivalent to Implanon. It also is indicated for three years of use and has similar removal instructions.
Nexplanon differs from Implanon in two ways. It features a new preloaded applicator, which is designed to reduce the risk of insertion errors. The device also is radio-opaque and can be located on an X-ray or CT scan if necessary.
The device is not available in the United States. However, it is now under review by the Food and Drug Administration as IMPLANON NXT, confirms Lee Davies, a spokesman for Merck & Co., the device manufacturer.
Review the options
In counseling women, it is important to note that no contraceptive is 100% effective, says Berenson. For women who can't remember to take the Pill everyday, don't want anything implanted in their uterus, and do want long-term contraception, Implanon is a good match, she states.
As with any contraceptive method, Implanon has advantages and disadvantages, according to A Pocket Guide for Managing Contraception. Implanon offers decreased menstrual and ovulatory cramping, and dysmenorrhea decreases by 48%. A disadvantage might lie in unpredictable or irregular menstrual bleeding. While such bleeding might persist, it usually is light and well-tolerated.4
"The spotting/bleeding is a real challenge, but many women really appreciate the true efficacy," says Nelson.
References
- National Health Services Knowledge Base. Implanon contraceptive implant examined. Accessed at http://www.nhs.uk/news/2011/01January/Pages/info-implanon-contraceptive-implant.aspx.
- Croxatto HB, Mäkäräinen L. The pharmacodynamics and efficacy of Implanon. An overview of the data. Contraception1998; 58(6 Suppl):91S-97S.
- Schering-Plough Corp. Implanon prescribing information. Accessed at http://www.spfiles.com/piimplanon.pd.pdf.
- Zieman M, Hatcher RA, Cwiak C, et al. A Pocket Guide for Managing Contraception. Tiger, GA: Bridging the Gap Foundation. 2010.
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