How IUDs Work

Rittenhouse Women’s Wellness Center currently offers the following IUD’s: Liletta, Kyleena, and Paraguard

We also offer the birth control implant: Nexplanon

Read this article from to understand what an IUD is, how they work, and what is the same about all of them!

Let’s start by looking at what hormonal and non-hormonal IUDs have in common:

  • They work. Really, really well. Both IUDs are ranked among the most effective birth control methods you could use, up there with having your tubes tied.
  • They’re safe. Pretty much anyone who wants to prevent pregnancy could use an IUD. And, to be clear, “pretty much anyone” DOES include people who have never given birth. (Bedsider’s article IUDs are A-OK will tell you more about how IUDs are safe for most people with a uterus—whether they’ve had a baby or not.) And we can add that IUDs are often safe for people with medical conditions that rule out other types of birth control.
  • They’re small. All the IUDs on the U.S. market are T-shaped, and the T itself is about as thick as a tampon string. The different IUDs vary slightly in size, but all are smaller than an Apple Watch.
  • They are affordable, especially in the long run. At present, insurers are required to cover IUDs with no out-of-pocket costs, so if you have health insurance, you should be home free. If you have to pay for an IUD up-front, it can seem expensive, but if you use it for at least a year, it is actually cheaper than most other forms of birth control. A clinic may be able to help you pay for an IUD in installments.
  • They are easy to start using. You can usually have the IUD inserted at your first visit to your health care provider. In most cases, having an IUD inserted takes about 60 seconds total.
  • An IUD will work for a long time, but you can stop using it any time you like. All five IUDs are FDA-approved to use for at least 3 years. Sklya is approved for up to 3 years of use; Mirena Kyleena are approved for up to 5 years; LILETTA is approved for up to 6 years; and Paragard is approved for up to 10 years. In practice though, LILETTA and Mirena have been found to be effective for 7 years and Paragard for 12 to 20 years. If you want to have an IUD removed sooner though, you can. Your provider should remove it for you if you want it removed. And whenever you do have the IUD removed, your chance of getting pregnant goes back to what is normal for you right away.
  • IUDs DON’T prevent sexually transmitted infections (STIs). Condoms and internal condoms (as well as dental dams, depending on what kind of sex you’re having) are still the only game in town for that.

How are the hormonal IUDs different?

All the hormonal IUDs prevent pregnancy by releasing a very small amount of a progestin hormone called levonorgestrel each day. The progestin acts locally in the uterus to prevent pregnancy. Compared to folks using the pill and some other hormonal methods, those using hormonal IUDs have much less hormone in their blood. Hormonal IUDs don’t contain estrogen, so they typically have fewer hormonal side effects than methods that do contain estrogen.

Many people who start using a hormonal IUD have irregular bleeding for the first 3-6 months after placement. This bleeding is usually more like spotting—light and not painful. But you may not be able to predict your periods for the first several months, so wear black underwear! After 6 months, some hormonal IUD users get very light periods or no period at all. Because of the different amounts of hormone, a woman using each IUD has a different chance of her period going away after one year: 20% for Mirena, 12% for Kyleena, and 6% for Skyla. If not having a period every month would make you sick to your stomach worrying that you’re pregnant, you might prefer a non-hormonal IUD.


1632 Pine Street
Philadelphia, PA 19103
Phone: 215-735-7992
Fax: 215-735-7991


Monday – Friday:  8am – 8pm

Saturday: 9am – 2pm

Sunday: Closed

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