The In’s and Out’s of the Intrauterine Device (IUD)
The Intrauterine Device (IUD) of today is a far cry from the versions used in the 1960s and 1970s. While the IUD has a complicated history, it has become one of the most effective and widely used forms of reversible contraception. Here’s a brief history, an explanation of how they work, and what you need to know about this game-changing addition to women’s reproductive health.
A Complicated History:
In the early 1900s, the IUD was used as part of the eugenics movement, a strategy for controlling the population growth of certain ethnic and socio-economic groups. It was seen as a tool to promote patriarchal and white supremacist reproductive control. Fast forward to today, and the IUD is considered one of the safest, most effective methods of reversible contraception available. It has become synonymous with an individual’s ability to gain control over their reproductive health and a safe and effective tool for family planning.
The History:
The first experiments with IUDs began in the early 1900s, when various forms of silkworm gut, sometimes coated with metals like silver or copper, were tested. The design evolved, and by the 1960s, the first modern IUD, the Lippe’s loop, was introduced. This nylon-stringed “double S” shaped device was relatively safe, reducing infection risks by eliminating the wicking effect of previous materials. It reduced the cramping that was common with other devices that protruded through the cervix by sitting inside the uterine cavity so that only the string protruded into the vagina.
The success of this new design coincided with the sexual revolution and more modifications were made to this type of contraceptive. In 1969, a T-shaped device was developed, though it had a high failure rate. Around the same time, copper was found to have spermicidal properties, which led to the creation of the Copper T-200. The following year saw the invention of the Progestasert, a T-shaped IUD with a small dose of progesterone, however, it was only effective for one year. Perhaps the most infamous IUD from this era was the Dalkon Shield. Shaped like a crab to help stay in place, it was made of plastic and copper. Unfortunately the string that was used for its removal allowed bacteria to travel into the uterus, causing severe infections, infertility, and even death. IUD use declined sharply as a result of these complications.
However, in 1984, the Copper T-380A, marketed as Paragard, made a comeback, offering 10 years of contraception. In 2000, hormonal IUDs entered the scene with the introduction of the Mirena, a "Y" shaped device containing levonorgestrel (LNG). Followed by Liletta, they were initially approved for five years but recently the efficacy was extended to eight years. Smaller versions like Skyla and Kyleena soon followed, providing a range of options for contraception Mirena and Liletta have also received FDA approval for treatment of heavy menstrual bleeding.
How IUDs Work
There are two main types of IUDs: hormonal (like Mirena) and copper (like Paragard). Both are highly effective but work in different ways.
● Hormonal IUDs (e.g., Mirena, Liletta, Skyla): These release levonorgestrel, a synthetic progesterone. The hormone thickens cervical mucus to block sperm, reduces sperm survival, and alters the lining of the uterus. This can result in lighter or absent periods.
● Copper IUDs (e.g., Paragard): These work by disrupting sperm transport and fertilization. Copper also causes inflammation in the uterine lining, which can make periods heavier and more painful. Importantly, copper IUDs do not affect ovulation or hormone production.
Risks, Complications, and Side Effects
Like any medical device, IUDs carry some risks. These include:
● Infection: Since the IUD is inserted into the uterus, there’s a risk of infection during or after insertion.
● Perforation: There’s a small risk that the IUD could puncture the uterus resulting in the full or partial protrusion of the IUD into the abdomen. This compilation occurs more frequently in the first six weeks after pregnancy or in breastfeeding/ chestfeeding individuals.
● Expulsion: In some cases, the IUD may be expelled from the uterus, eliminating its contraceptive effectiveness.
● Menstrual Changes: The most common side effect is changes in menstruation, including irregular bleeding, cramping, or pelvic pain, especially in the first few months. Some users may also experience vaginal discharge, acne, or benign ovarian cysts (more common with hormonal IUDs like Mirena). The copper IUD may cause more noticeable cramping and heavier periods.
Insertion:
The insertion of an IUD can vary in discomfort, with some individuals experiencing minimal pain and others reporting more intense cramping. Insertion is generally more comfortable and there is less chance of infection when done during menstruation.
Here’s what typically happens during insertion:
1. Consent and Preparation: Your healthcare provider will review the risks, benefits, and alternatives before obtaining your consent.
2. Cervical Visualization: A speculum (the same device used for a pap smear) will be placed in the vagina and the cervix (the lowest part of the uterus that sits in the vagina) will be visualized. The speculum is sometimes metal and sometimes plastic.
3. Cleaning: The cervix is cleaned with betadine to decrease infection risk.
4. Cervical Stabilization: The cervix may need to be stabilized with a device that when attached to the cervix can cause cramping.
5. Cervical Dilation and Measurement of the Uterine Cavity: If necessary, a dilator is used to gently open the cervix followed by a long thin stick like instrument that measures the length of the uterus. A cramp may be felt as the measuring stick touches the uterus.
6. IUD Insertion: The IUD is then inserted through a thin tube (the introducer) into the uterus, which will cause another cramp.
7. Final Steps: The IUD strings are trimmed to about 1-2 cm from the cervix, and the
speculum is removed. To reduce discomfort, pain-relieving medications like ibuprofen or naproxen are recommended before and after the procedure. Some providers may prescribe misoprostol to soften the cervix, and research is ongoing into the use of local anesthetics to numb the cervix.
What to Expect After Insertion
After insertion, cramping usually decreases, but some discomfort may persist for days or even weeks. It’s normal to experience irregular bleeding, particularly with hormonal IUDs, which may continue for weeks or months. This bleeding typically gets lighter over time, except during menstruation when it may temporarily increase.
You should avoid unprotected sex for at least two weeks post-insertion. If you experience increased pain, fever, or unusual discharge, it’s important to contact your healthcare provider, as these could be signs of infection or other complications.
Gender Inclusivity Notice
While this post uses the term "women" to refer to cisgender women, it’s important to recognize that many individuals of various genders can have uteri and may use IUDs. The terminology used in some studies and reports reflects this historical bias, but we acknowledge the full spectrum of people who benefit from reproductive health options like IUDs.
Works Cited
1. Bayer Pharmaceutical Companies. Mirena (levonorgestrel-releasing intrauterine
syster) 52 mg U.S. Food and Drug Administration website
https://www.mirenahcp.com/about-mirena/efficacy Modified: 08/2024. Accessed
1/25/2025. .
2. Lippes loop and the first IUDs: lessons from a bygone era Peipert, Jeffrey F.
American Journal of Obstetrics & Gynecology, Volume 219, Issue 2, 127 - 128
3. CooperSurgical. Paragard. U.S. Food and Drug Administration. Website -
https://hcp.paragard.com/wp-content/uploads/2018/09/PARAGARD-PI.pdf iss.
7/2021. Accessed January 25, 2025
4. Corbett, Megan, and Brandy Bautista. “Reproductive Health Access Project | A
History:The IUD
5. Reproductive Health Access Project.” Reproductive Health Access Project |, 20
March 2024, https://www.reproductiveaccess.org/2024/03/a-history-the-iud/.
Accessed January 10, 2025.