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How Does an IUD Work?

An intrauterine device (IUD) is a small, T-shaped device that is inserted into the uterus to prevent pregnancy. IUDs are one of the most effective forms of birth control available. The likelihood of pregnancy with a copper IUD is < 1% and with a levonorgestrel IUD is < 0.2%. Once an IUD is inserted, it is effective until it is removed – no more worrying about missing a pill, patch, or injection dose! If you are interested in learning more about how an IUD works, then this blog will give you the information you need.

In addition to pregnancy prevention, there are many other benefits to using an IUD. Levonorgestrel IUDs can help to regulate your menstrual cycle and reduce your risk of endometrial cancer. For women who do not yet have an IUD, an IUD can be used as emergency contraception if inserted within 5 days of unprotected sex. IUDs provide a readily reversible contraceptive method: once women remove the IUD there is an immediate return to fertility, compared with a potential delay of several months when using a combined hormonal contraceptive that inhibits ovulation.

Who can use IUD?

IUDs can be used by women of all ages, including teenagers and women who have never been pregnant. In fact, IUDs are often recommended for teenagers and women who are not yet ready to have children but who want a long acting, highly effective form of birth control.

IUDs are also a good option for women who cannot take estrogen or who want an effective contraceptive method that does not involve hormones. There are two types of IUDs available in the United States: the copper IUD and the levonorgestrel (progesterone) IUD.

How do IUDs work?

Both IUDs inhibit fertilization by affecting sperm movement or viability.

The copper IUD is a T shaped device that is wrapped with copper wire. The copper wire creates a sterile (noninfectious) inflammation that is toxic to sperm, preventing egg fertilization. The copper IUD can be used for up to 10 years and is over 99% effective at preventing pregnancy. The most common side effects are cramping and heavy menstrual bleeding.

The levonorgestrel IUD is a T shaped device that releases progesterone slowly over time. The progesterone thickens the cervical mucus, making it difficult for sperm to reach the egg. The hormonal IUD can be used for up to 8 years and is over 99% effective at preventing pregnancy. Common side effects in less than 10% of users include headaches, nausea, breast tenderness, mood changes, acne, and ovarian cyst formation.

Both types of IUDs are safe and effective for most women. However, IUDs do not protect against sexually transmitted infections (STIs), such as chlamydia, gonorrhea, trichomonas, or HIV. If you are at risk for STIs, it is important to use condoms in addition to an IUD.

How is an IUD Inserted?

The IUD is inserted during an office visit. It is best to take ibuprofen or Tylenol prior to the visit to help with cramping during the procedure. Sometimes your provider may recommend a dose of misoprostol prior to insertion. Your health care provider will start with a bimanual examination to feel the shape of the uterus. Most women have an anteverted (forward tilting) uterus, and some will have a retroverted (backwards tilting) uterus. Both are normal positions but should be assessed prior to insertion to help ensure the IUD is placed correctly. Next, a speculum is placed into the vagina and opened to visualize the cervix. Sterile soap, usually betadine, is placed on the cervix to reduce the risk of infection. The uterus is then measured with a thin stick called a sound, which will evaluate the length of the uterus in centimeters. The IUD insertion device is then inserted through the cervix and the IUD is released into the uterus. This part can feel crampy. Once the IUD is in place, the insertion device is removed, and the strings are trimmed so that they can be seen just outside the cervix. The strings help your provider check to ensure the IUD is in place and are used to remove the IUD when treatment is complete.

What are the risks of an IUD insertion?

Overall, complications with IUDs are rare and include expulsion, method failure, and perforation. The expulsion rate is between 2% and 10% during the first year of use. Women who have an expulsion often experience heavy cramps and bleeding before the IUD is expelled, so women experiencing these side effects should call their provider for evaluation. Perforation is rare, occurring in approximately 1 in 1000 IUD insertions. Women who have an IUD should have regular checkups with their gynecologic provider, who can check the strings and ensure the IUD is in the correct position.

Final Words

If you are thinking of getting an IUD or considering any other forms of birth control, contact Essex County OB/GYN Associates to speak to a women’s health care professional who can help choose the best option for you.

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