IUDs, implants advocated for birth control

By Amy Norton

NEW YORK (Reuters Health) - IUDs and contraceptive skin implants are the most effective type of reversible contraceptive, and should be offered as options to most women seeking birth control, according to the American College of Obstetricians and Gynecologists (ACOG).

IUDs, or intrauterine devices, are inserted into the uterus, where they release small amounts of either copper or the hormone progestin to prevent pregnancy. The contraceptive skin implant, about the size of a matchstick, is inserted under the skin of the arm, where it releases controlled amounts of progestin.

In the U.S., IUDs and implants are much less popular than birth control pills and condoms for contraception. In 2008, IUDs were the chosen method of 5.5 percent of women using contraceptives - up from 1.3 percent in 2002. Contraceptive skin implants were only approved in 2006, so there's little information tracking their use but "millions of women worldwide" have tried the implants, the authors claim.

These long-acting "reversible" contraceptive methods are highly effective, ACOG says, and more women should be aware of that.

"They're great," said Dr. Eve Espey, who helped write the new ACOG report, published in its journal Obstetrics & Gynecology.

"They're very effective, and they have a good safety profile," said Espey, a professor of obstetrics and gynecology at the University of New Mexico in Albuquerque.

IUDs and implants are so effective, Espey told Reuters Health, because they are essentially "no maintenance."

The hormonal IUD, sold under the brand-name Mirena, can prevent pregnancy for five years, while the copper version, sold as ParaGard, is effective for about 10 years. The contraceptive skin implant (Implanon) works for three years.

That's in contrast to birth control pills and other reversible forms of contraception, which require consistent and correct use.

According to ACOG, research has shown that IUDs and contraceptive implants are more effective.

A study earlier this year found that 0.8 percent of U.S. women using a copper IUD had an unplanned pregnancy within a year. The rate for those on the hormonal IUD was 0.2 percent.

Contraceptive skin implants, meanwhile, are even more effective - with a one-year pregnancy rate of 0.05 percent.

In contrast, about 9 out of every 100 women on birth control pills can expect to have an unintentional pregnancy in a year -- owing largely to imperfect use. With condoms, about 2 percent of women will become pregnant, but that's only if a couple uses them correctly, every time they have sex.

Both IUDs and skin implants can have side effects, ACOG points out. With the implant, irregular menstrual bleeding is most common; some women stop having their periods altogether. Acne and weight gain are also frequently reported with all kinds of hormonal contraceptives; mild insulin resistance has been seen with the contraceptive skin implant.

The Mirena IUD may also cause menstrual irregularities. But it generally makes periods lighter, which is why it is also approved as a treatment for heavy bleeding. The ParaGard IUD has the opposite effect: menstrual bleeding and cramping can increase, though that may subside over time.

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