Few U.S. women choose intrauterine devices, or IUDs, for contraception — a recent study found they rank No. 5 in use, behind oral contraceptives, tubal ligation, condoms and vasectomies.

But IUD use is much more common among one group of women: gynecologists. According to a poll released by the American College of Obstetricians and Gynecologists (ACOG), use of IUDs by female ob-gyns is three times greater than that of the general public.

If the women who are, presumably, the most knowledgeable about reproductive health are choosing IUDs more oftenthan the rest of us, then what is it our gynecologists know that most women don't?

Why gynecologists love IUDs

IUDs are an excellent birth control option because they are effective, safe and easy to use, said Dr. Sara Pentlicky, a gynecologist and family planning specialist at the University of Pennsylvania.

While some women can't use estrogen-containing birth control because of health issues, “there are very few women who can't use an IUD,” Pentlicky said. She estimated that 80 percent of the female doctors in her practice use IUDs for their own contraception.

IUDs have to be inserted by a doctor, but once in place, they are effective immediately and can protect against pregnancy for five to 12 years, depending on the type.

Unlike birth control pills, which require that users remember to take them on a daily basis, IUDs need little to no maintenance. They are nearly 99 percent effective, according to a study published in May in the New England Journal of Medicine.

IUDs also differ from birth control pills in that women have a greater chance of becoming pregnant immediately after stopping use.

In the U.S., there are two IUDs available — ParaGard, a copper, hormone-free device that can protect against pregnancy for up to 12 years, and Mirena, which releases small amounts of a synthetic progestin hormone and can be effective for up to 5 years.

“With ParaGard, you don't actually stop ovulating like you do with the pill, so when I take it out, you should be able to get pregnant the next month without any trouble,” Pentlicky said.

The misconceptions

Despite being highly regarded by experts in the field, IUDs have yet to gain popularity in the U.S. In 2008, 5.5 percent of women reported using them, while 28 percent reported using birth control pills, according to a 2010 report from the Centers for Disease Control and Prevention.

The low rate of IUD use may stem from the common misconception that IUDs cause infertility, and thus should only be used by women who do not want any more children, Pentlicky said.

This concern is rooted in real problems with IUDs that occurred in the 1970s, when the first device, called the Dalkon Shield, was found to be associated with pelvic inflammatory disease, which can cause infertility.

Further research, however, revealed that the association found between IUDs and pelvic inflammatory disease may not necessarily have been due to the device itself. There was a general increase in the prevalence of sexually transmitted infections around the time the Dalkon Shield was introduced, and that likely contributed to the rate of infections seen in women using the device, several studies concluded.

Women are now tested for infections before IUDs are put in, and much of the danger has been eliminated, Pentlicky said.

There is also some evidence that the braided string of the original Dalkon Shield, which was used to remove the device, essentially acted as a ladder, allowing bacteria in the vagina to move up into the uterus. Modern IUDs have a thin, monofilament string, similar in feel to fishing wire, to address this concern, Pentlicky said.

“We now know that the IUD doesn't cause infection, but there's still this perpetuated myth that the IUD can cause infertility, which is just untrue,” Pentlicky said. In fact, the hormonal IUD Mirena causes cervical mucus to thicken, which may actually decrease the risk of pelvic inflammatory disease by preventing bacteria from moving up through the cervix.

The percentage of women who develop pelvic inflammatory disease while using Mirena is less than 1 percent, according to the company's website.

But IUD use does carry risks. ParaGard has been associated with heavy bleeding, severe cramping and vaginal inflammation, while Mirena may be associated with hormonal side effects, such as acne, weight gain or mood changes. Neither device protects against sexually transmitted infections.

The devices cost between $500 and $1,000, and are not covered by all insurance plans, so there is often a higher up-front cost for IUDs than for other forms of contraception. But because they last for many years, IUDs are ultimately the more cost-effective option, according to the ACOG.

The future of contraception

The ACOG recommended in July 2011 that IUDs be offered as a first-line contraceptive for most women. Moreover, expanding access to long-acting reversible contraception for young women was declared a national priority by the Institute of Medicine.

Although experts agree that IUDs are still underutilized, one recent [s1] study found that the use of long-acting forms of contraception, including IUDs, has been steadily increasing.

So what does your gynecologist know about IUDs that you don’t?

“They take the stress of preventing pregnancy away, which is huge for a lot of women,” Pentlicky said.

Pass it on: Intrauterine devices are more commonly used by gynecologists than by other women.