Photo: Gluekit

You can’t tell a woman’s method of birth control by looking at her, but you’ll know if she’s using an IUD, or intrauterine device, because she won’t be able to shut up about it. My friends who have IUDs, not known to recommend so much as a hairdresser, extol the virtues of the device with the unsolicited but contagious conviction of the Avon lady. The difference is they’re not making a commission.

I mentioned this phenomenon to an acquaintance, Lisa, who said she, too, was getting it from all sides. Two out of three of her closest friends have IUDs, which once turned a dinner conversation into a two-on-two conversion mission. Meanwhile, a cousin tipped her off to a Planned Parenthood program that offers free IUDs to qualified women. Lisa wasn’t looking for a new form of birth control. But, like a line on a room in a rent-stabilized apartment or a too-good-to-be-true sample sale, the benefits of the IUD appear to be too great to keep to one’s self. “Women who have IUDs seem eager to defend them and argue in favor of switching to them,” she said.

They begin by explaining that the T-shaped device (“Smaller than a penny!”) is inserted by a doctor or nurse (“You’re in and out in fifteen minutes”) and remains in the uterus (“I’m part bionic”), preventing pregnancy for up to ten years with minimal side effects — other than the quasi-religious fervor.

My unscientific survey suggests that a vocal IUD enthusiast can convert (and will brag about converting) two women each year. Call it IUD evangelism; the voluntary mandate among users to spread the good news appears to be working. In 2002, IUDs made up 2 percent of Americans’ contraceptive use. Now combined use of the ParaGard copper IUD and Mirena hormonal IUD accounts for more than 10 percent, and the rate is expected to continue rising, thanks to inclusion in the Affordable Care Act’s contraception coverage mandate and the strange blend of word-of-mouth marketing and feminist consciousness-raising they inspire.

“I sound like a ParaGard commercial sometimes,” begins a comment in one of the more than 4,700 IUD-related threads on Mothering.com. Web searches reveal that getting an IUD is an occasion worth tweeting about. Jezebel writer and “part-time IUD evangelist” Jenna Sauers blogged her IUD insertion two years ago and recently proclaimed her enduring love for the device at a potluck brunch. She’s not sure how many women she’s converted over the years — boozy, late-night conversations about contraception don’t lend themselves to follow-up, she says — but confirmed the tribe exists. “IUDs inspire a sort of cultish loyalty,” she said, “in part because they’re so difficult to obtain.”

Photo: Gluekit

With up-front costs of up to $1,000 for the device and insertion and doctors who needlessly discourage young women from getting them, the IUD is in some ways the Birkin bag of birth control — expensive, exclusive, and European. Although it was once poised to be the pill’s sidekick in the sexual revolution, an aggressively marketed and fatally defective seventies model, the Dalkon Shield, waylaid the IUD’s popularity when it was recalled amid a highly publicized, asbestos-scale class-action lawsuit. Nonetheless, its reputation held in Europe, where about 20 percent of contraceptive-using women currently have one.

For those who came of age during the post-Dalkon blackout, learning about the IUD is like discovering that some benevolent God has been listening to your specific complaints about being a woman and will deal with them one at a time. Are you tired of refilling birth control prescriptions? Can’t remember where you left your pills? With the IUD, you’re baby-proof for up to ten years. (Doctors call it the “set it and forget it” method, like the rotisserie ovens sold on TV.) Do the hormones in birth control pills make you cry, as one IUD evangelist put it, “at the tiny hand in the March of Dimes commercial?” The copper IUD is hormone-free. Don’t trust him to pull out punctually? Sick of searching for the elusive Sponge? The IUD is as effective as sterilization until you take it out. (Although, as with tubal ligation, things happen.) As one IUD-using friend puts it in an e-mail she sends to potential converts, “it’s like being a man.”

Nellie, 28, first heard about the IUD in her early twenties, while visiting her mother, a physician who was stationed in West Africa. From USAID workers there, she learned that the IUD is among the most popular methods of birth control worldwide, favored in countries where men resist condom use. “I asked my mom, ‘Why didn’t I ever learn about it?’” Like many educators, her mother attributed the older generation’s IUD silence to lingering anxiety over Dalkon Shield with a dash of old-fashioned American Puritanism. One of Dalkon Shield’s disastrous side effects was pelvic inflammatory disease, a complication of gonorrhea and chlamydia that can cause infertility. Consequently, some doctors can be reluctant to prescribe IUDs to women who haven’t finished having children or sleeping around.

Nellie got her IUD easily and cheaply at Planned Parenthood and she’s since converted two friends, though one backed out mid-insertion. To a certain extent, the sisterhood of the IUD is forged in the stirrups: The device is inserted into the uterus is through the cervix, which can hurt. Women struggle to describe the brief but memorable discomfort.

“It’s a visceral kind of reaction,” said Allison, a 27-year-old M.B.A. candidate. On the recommendation of a friend, Allison switched to the IUD after having a bad reaction to the pill. “It’s unlike any other medical thing I’ve ever had done before.” But not bad enough to discourage her from talking it up to friends, one of whom is in the process of getting one.

The biggest upgrade to the IUD since the Dalkon Shield is in the one- to two-inch string threaded through the cervix to hang down into the vagina to ease removal, said Dr. Linda Prine, the medical director of Reproductive Health Access Project who trains family doctors in IUD insertion. In the past, the strings were made from a multifilament that “wicked” bacteria into the uterus. Now, Dr. Prine explained, the strings are made of monofilament that doesn’t facilitate the transfer of bacteria. The hormonal IUD, meanwhile, causes the body to produce — brace yourself — a cervical mucus that’s like a “plug” against infections. As long as you don’t have an STD at the time of insertion, the IUD comes with no additional risk of pelvic inflammatory disease. Monogamy is no longer required.

Accordingly, American College of Obstetricians and Gynecologists recommended IUDs “as a first-line contraceptive option” for sexually active teenagers this year, but it’s not likely they’ll know to ask for it. Reproductive rights group NARAL Pro-Choice New York recently found that about a third of 16- to 17-year-old women don’t know anything about the IUD, and one in five 18- to 25-year-olds had never heard of it either. Meanwhile, Mirena commercials feature a middle-age mom listing the things that bourgie white ladies can accomplish in five years if they don’t have another baby (Learn French! Go skiing!) and the Paragard commercials subtly suggest that the woman who chooses BGH-free milk might also choose hormone-free birth control.

“Imagine hearing that one in five women had never heard of the pill or the condom,” said NARAL Pro-Choice New York president Andrea Miller. “Your head would spin!” The organization co-sponsors the pink-and-black website Maybe the IUD? with the hopes of educating more young women.

Kathryn Scharton, 28, already knew the benefits of the IUD. She made a living recommending it and other birth-control methods to patients at the Philadelphia abortion clinic where she worked as a counselor. But she never seriously considered getting one for herself until her colleagues began to, recommending the best over-the-counter pain relievers to take prior to insertion.

“They celebrate their anniversaries with their IUDs,” she said.

But when Kathryn’s doctor only grudgingly agreed to give her an IUD if she insisted, Scharton realized that not all medical professionals share IUD user’s devotion to the device. “That ended the conversation. It shut the door with her.” Similarly, Jenna was turned away by several doctors, and Nellie ditched the gynecologist who said she never would have given her one.

“Many providers are not up to date on the research,” said Dr. Sophia Yen, an adolescent medicine specialist at Stanford’s Lucille Packard Children’s Hospital who thinks the IUD is an underrated strategy for preventing teen pregnancies. Others may simply be uncomfortable with insertion procedures. According to a March study from the Center for Disease Control, doctors who aren’t trained in IUD insertion are more likely to play up its safety risks. Dr. Yen thinks the IUD’s popularity will continue to grow as more young doctors switch to the IUD, which she says is popular among residents working long and irregular hours. But they might need to take a cue from their happy patients and proselytize. According to unpublished research, Dr. Yen said, if a provider feels comfortable personally disclosing that she uses an IUD, a young patient is more likely to use it.