The nurse slides open a drawer and pulls out a model of the cervix and uterus. Inside the uterus is a two-pronged, plastic object about the length of a pinkie finger. A nearly-invisible string extends out of its end and through the cervix. She tugs the string, and the object dislodges itself smoothly into the palm of her hand.

“This is an intrauterine device,” she says.

An intrauterine device, commonly called an IUD, is placed into the uterus to prevent unwanted pregnancies. The gynecologist inserts the device once, where it remains in place for five to seven or 10 to 12 years, depending on the type of IUD. Any human error that comes with remembering to take a pill or insert a diaphragm is eliminated. Only 0.2 to 0.8 percent of women with IUDs have unplanned pregnancies per year. The Pill, in comparison, comes in at around nine percent per year.

An IUD can reduce the length and heaviness of the woman’s period and can be removed at any time. It doesn’t have the side effects associated with The Pill, such as weight gain, mood swings and nausea.

Despite advantages over other forms of birth control, the IUD is still a mysterious entity to many women.

There are two types of IUDs: copper- or hormone-based.

The copper model, called Paraguard works by periodically releasing small doses of copper into the uterus. It spurs a brief inflammatory reaction, calling up troops of white blood cells. The blood cell fluid kills sperm instantly.

An IUD also can work as a morning after pill because the inflammation prevents a fertilized egg from settling in the uterus.

The hormone-based IUD, Mirena, prevents pregnancy just like oral contraception. It thickens mucus in the cervix to prevent sperm from getting through to the uterus and slows the growth of the uterine lining.

Emily*, a University of Florida student, was on The Pill for four years. She didn’t have any problems with it but wanted to switch to an IUD because she saw it as a better form of birth control. By choosing the copper form, she could avoid putting unnecessary hormones in her body.

“I wanted to see what my body was like in its natural state,” she said.

Emily wasn’t nervous until the day before the procedure. But for some women, fear of the insertion process prevents them from considering IUDs altogether. According to Karen Brown Williams, a specialist at the UF Women’s Health Clinic, the process is like getting a tooth filled.

“It’s not surgery, but it is a sterile procedure,” she said.

Before anything is inserted, the woman must pass a STD screening and a pregnancy test.

For the procedure, the woman returns to the clinic during her period, because this is when the cervix is slightly more relaxed and open. The woman settles in to the usual gynecologist-visit position: legs in the stirrups. The vagina is held open with a speculum, an instrument that widens the opening of the vagina, making the cervix is more easily visible and giving the nurse access the uterus. Then the nurse inserts the tenaculum, which is used to pinch the cervix and hold it steady.

The nurse loads the IUD into a tube about the size of a finger. It slides partially into the cervix with the IUD inside — the T-shaped arms are flattened — and pushes into the cervix. It settles into place and spreads its arms. The string hangs out slightly; the nurse will trim it so that it is not bothersome.

For Emily, the insertion process was three minutes of discomfort. She felt cramps immediately after, which is expected, but within fifteen minutes they subsided.

“It was nothing Ibuprofen couldn’t fix,” she said.

Although she was uncomfortable, she reminded herself about the long-term benefit: a decade of birth control without hormones.

* Last name omitted for privacy