What Is an IUD?
An intrauterine device (IUD) is a small, T-shaped contraceptive device inserted into the uterus by a healthcare provider. IUDs are among the most effective forms of reversible contraception available, with failure rates of less than 1% per year — comparable to permanent sterilization. They are also among the most cost-effective long-term contraceptive options, as a single device can provide protection for 3-10 years.
IUDs have experienced a significant resurgence in popularity over the past decade. In the United States, IUD use among contraceptive users increased from approximately 5% in 2002 to over 14% by 2017, driven by growing evidence of their safety, effectiveness, and convenience.
Types of IUDs
There are two main categories of IUDs: hormonal and non-hormonal (copper).
Hormonal IUDs
Hormonal IUDs release a small amount of levonorgestrel (a progestin) locally into the uterus. Available brands include:
Mirena: 52mg levonorgestrel, effective for up to 8 years. Typically causes very light periods or no periods at all.
Kyleena: 19.5mg levonorgestrel, effective for up to 5 years. Designed for women who have not had children. Smaller than Mirena.
Liletta: 52mg levonorgestrel, effective for up to 8 years. Similar to Mirena but often lower cost.
Skyla: 13.5mg levonorgestrel, effective for up to 3 years. The smallest hormonal IUD, designed for women who have not had children.
How Hormonal IUDs Work:
- Thicken cervical mucus, preventing sperm from reaching the egg
- Thin the uterine lining, reducing implantation likelihood
- In some cases, suppress ovulation (though this is not the primary mechanism)
Copper IUD (Paragard)
The copper IUD is the only non-hormonal long-acting reversible contraceptive available. Paragard is effective for up to 10-12 years.
How the Copper IUD Works:
- Copper ions are toxic to sperm, impairing motility and fertilization
- Creates a local inflammatory reaction in the uterus that is hostile to fertilization
- Can also be used as emergency contraception if inserted within 5 days of unprotected sex (99%+ effective)
Who Is a Good Candidate for an IUD?
IUDs are appropriate for most women, including:
- Women who want long-term, highly effective contraception without daily action
- Women who have completed their families but are not ready for permanent sterilization
- Women who cannot use estrogen-containing contraceptives
- Breastfeeding mothers (hormonal IUDs are safe postpartum)
- Adolescents (IUDs are appropriate for teenagers and women who have not had children)
- Women with heavy, painful periods (hormonal IUDs significantly reduce menstrual bleeding)
IUDs may not be appropriate for women with:
- Unexplained vaginal bleeding
- Current STI or pelvic inflammatory disease (PID)
- Uterine abnormalities that distort the uterine cavity
- Copper allergy or Wilson's disease (for copper IUD)
The Insertion Procedure
IUD insertion is an outpatient procedure performed in a healthcare provider's office, typically taking 5-10 minutes. The process involves:
- A pelvic examination to assess uterine position and size
- Insertion of a speculum
- Measurement of the uterine depth with a thin instrument (uterine sound)
- Insertion of the IUD through the cervix into the uterus
- Trimming of the IUD strings to an appropriate length
Pain Management: Insertion can cause cramping ranging from mild to significant. Taking ibuprofen 1-2 hours before the procedure can help. Some providers offer local cervical anesthesia. Pain typically subsides within a few hours.
Timing: IUDs can be inserted at any point in the menstrual cycle, though insertion during menstruation may be slightly easier as the cervix is naturally more open.
What to Expect After Insertion
First Few Days: Cramping and spotting are common and typically resolve within 1-2 days. Avoid tampons, sexual intercourse, and swimming for 24 hours.
First 3-6 Months (Copper IUD): Periods may be heavier, longer, and more painful, particularly in the first 3-6 months. This typically improves over time.
First 3-6 Months (Hormonal IUD): Irregular spotting is common as the body adjusts. Periods typically become lighter over time.
Ongoing: Check IUD strings monthly (particularly in the first year) to confirm the device is in place. See your provider if you cannot feel the strings or feel the hard plastic of the device.
Effectiveness and Failure
IUDs have a failure rate of less than 1% per year, making them among the most effective reversible contraceptives available. In the rare event of IUD failure resulting in pregnancy, there is an increased risk of ectopic pregnancy, which requires immediate medical attention.
Removal and Return to Fertility
IUD removal is typically quick and straightforward. Fertility returns almost immediately after removal of hormonal IUDs, and within one menstrual cycle for copper IUDs.
Frequently Asked Questions
Does an IUD protect against STIs? No. IUDs provide no protection against sexually transmitted infections. Use condoms for STI protection.
Can I use tampons with an IUD? Yes, tampons are safe to use with an IUD.
Will I feel the IUD during sex? You should not feel the IUD itself. Your partner may occasionally feel the strings, which can be trimmed shorter if needed.
Can an IUD fall out? IUD expulsion occurs in approximately 2-10% of users, most commonly in the first year. This is why monthly string checks are recommended.
Always consult a healthcare provider to determine if an IUD is appropriate for your individual health needs.