(CBS) The U.S. Food and Drug Administration has approved a new "set-it-and-forget-it" birth control method for women, and The Early Show medical correspondent Dr. Emily Senay explained more about it on Thursday's program.

Implanon is the name of this implantable contraceptive. It's designed to prevent pregnancy for three full years after a doctor places it under the skin of a woman's arm. That means three years of not worrying about taking birth control pills daily, or changing Ortho-Evra patches weekly, or replacing Nuva-rings monthly.

The device is one-and-a-half inches long (about the size of a matchstick), and it's placed in the woman's forearm. A fertility expert who helped conduct the clinical trials on Implanon told Senay it takes about a minute for the doctor to use a simple instrument to insert it, after the woman receives a local anesthetic.

The device remains under the woman's skin for three years, or until the woman decides she wants to become pregnant and has it removed, which takes just a couple of minutes. Ovulation is supposed to resume the next menstrual cycle.

Implanon is seen as an improvement over Norplant, which went on the market in 1990. Instead of a single, implantable rod (like Implanon), Norplant consisted of six rods that sat under a woman's skin for as long as seven years.

But Norplant was a cruder technology. Rods were harder both to insert and to remove. Norplant also produced unpleasant side effects in some women, including skin problems. Norplant's manufacturer, Wyeth, pulled that product off the market in 2000, after a number of women filed lawsuits, either because of the side effects or because of injuries they suffered when the rods were removed.

So what makes the experts think that a woman's experience with Implanon will be smoother?

For one thing, says Senay, the FDA says doctors won't be allowed to prescribe and implant this product until they've received formal training in the procedures involved. Also, the product has a track record — 30 other countries have permitted the use of Implanon for as long as eight years, and the side effects associated with Norplant apparently have not occurred.

That does not mean that Implanon will be trouble free. Women who use the product are more prone to spotting at unpredictable times and they need to be prepared for that unpredictability. There also are the risks of side effects that come with any contraceptive, including blood clotting.

But, on the plus side, it's been found to be more than 99 percent effective at preventing pregnancy. It also is designed to maintain sufficient hormone levels to help preserve bone strength and the integrity of other organs, including the breasts. And, of course, if a woman is suited to this product, the convenience of it may be very appealing.

Doctor training for Implanon should begin in the next few months, and the manufacturer predicts this contraceptive will become widely available next year.

Source: CBS News