New review boosts knowledge of implants

Your next patient is a young mother of three who is looking for long-term, effective contraception. She says she is not ready to consider tubal sterilization. What methods can you offer her?

One option is the contraceptive implant Implanon (Organon USA; Roseland, NJ). A small, thin, hormonal contraceptive that is effective for up to three years, Implanon was approved in July 2006 by the U.S. Food and Drug Administration. The device, made of a soft medical polymer, contains 68 mg of the progestin etonogestrel. Implanted in the inner side of a woman's upper arm during an in-office procedure, the matchstick-sized device releases the drug in a low, steady dose.

A just-published review provides an overview of the effectiveness and tolerability of subdermal contraceptives.1 The review includes information on Implanon, as well as Jadelle, a two-rod implant developed by the Population Council in New York City, and Norplant, a six-rod implant formerly manufactured by Wyeth Pharmaceuticals in Madison, NJ. Norplant has been unavailable in the United States since 2000; Jadelle has not been introduced in the United States. (Wyeth Pharmaceuticals suspended shipment of Norplant implants in August 2000 when concerns arose about efficacy of suspect lots. While the lots were found effective in July 2002, the manufacturer chose not to reintroduce the product in the United States.)

What do implants offer?

The new review was designed to assess the effectiveness and tolerability of subdermal implantable contraceptives compared to other reversible methods of contraception. Researchers used database searches and reference lists, and they interviewed individuals and organizations working in the contraceptive field to identify all randomized and controlled trials comparing subdermal implants with other forms of reversible contraceptives.

The researchers found that all studied implants were good at preventing pregnancy. No one subdermal implant was found to be any more or less effective than the others in preventing unwanted pregnancies.1

Most women who use contraceptive implants chose to continue with the method long term, the new report states. More than 80% of women still were using the implant method at two years, researchers found. Women in developed country studies were less likely to continue with these methods when compared to women in developing country studies.1

Device removal was quicker for Implanon and Jadelle than for Norplant, according to the new report. Mean time for Implanon insertions was 1.1 minutes; removal time was 2.6 minutes.1 Insertion problems were rare with any of the implants; problems during removal were uncommon, but they were significantly more likely to occur in Norplant users than Implanon users.1

Counsel on bleeding

When counseling women about the advantages and risks of using Implanon, providers must educate prospective patients about bleeding issues, says Jo Power, MRCOG, MFFP, a researcher at Margaret Pyke Center in London and lead author of the review.

"I think it is important that women choosing this method understand that their bleeding patterns may be unpredictable," notes Power. "Bleeding patterns vary from woman to woman and may also change with time for any individual woman; patterns may include no bleeding, infrequent, frequent, or prolonged bleeding."

According to the Implanon patient package insert, the most common side effect of the method is a change in menstrual periods. Women should expect their menstrual periods to be irregular and unpredictable throughout the time they are using the method. Women may have more bleeding, less bleeding, or no bleeding, advises the insert. The time between periods may vary, and spotting may occur in between periods.

Menstrual bleeding patterns in Implanon were similar to Norplant in comparative trials; however, amenorrhea occurred more with Implanon, said Anita Nelson, MD, professor in the obstetrics and gynecology department at the University of California in Los Angeles (UCLA) and medical director of the women's health care programs at Harbor — UCLA Medical Center in Torrance.2 Normal menses returned within three months in almost all women following removal.3

References

  1. Power J, French R, Cowan F. Subdermal implantable contraceptives versus other forms of reversible contraceptives or other implants as effective methods of preventing pregnancy. Cochrane Database Syst Rev 2007 Jul 18; (3):CD001326.
  2. Nelson A. Our newest option: Single-rod implantable contraceptive. Presented at the Contraceptive Technology conference. San Francisco and Washington, DC; March 2007.
  3. Zheng SR, Zheng HM, Qian SZ, et al. A randomised multi-center study comparing the efficacy and bleeding pattern of a single-rod (Implanon™) and a six-capsule (Norplant™) hormonal contraceptive implant. Contraception 1999; 60:1-8.