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What to know about IUDs, the most effective method of birth control

This tiny device can protect your uterus for up to 12 years.

Contraceptive IUD inserts. Credit: Reviewed / Getty Images / bortonia

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For effective, long-lasting birth control, it’s hard to beat an IUD, a.k.a. “intrauterine device,” for foolproof pregnancy protection. An IUD can live in your uterus for up to 12 years, protecting you from unwanted pregnancy with more than 99% effectiveness. IUDs are safe and reliable, but is there a catch? We talked to OB-GYNs about how this semi-mysterious method of birth control works, and what you should be aware of before having one put in your body.

What is an IUD?

Person holding IUD insert in palm of hand.
Credit: Reviewed / Getty Images / flocu

This T-shaped contraceptive method is inserted directly into the uterus so there's no need for timely phone reminders or painful injections.

Made of plastic and/or copper, IUDs are semi-flexible, T-shaped devices no bigger than the size of a small sugar packet. They’re inserted by a gynecologist and have two short strings attached at the bottom, which makes removal less arduous when it comes time to do so. The FDA currently approves of five devices: Paragard, Mirena, Kyleena, Liletta, and Skyla.

There are two types of IUDs you can get: hormonal and non-hormonal. Mirena, Kyleena, Liletta, and Skyla are hormonal IUDs, while Paragard is hormone-free. Both hormonal and non-hormonal IUDs prevent pregnancy by damaging or killing sperm, making it more difficult for them to swim to and fertilize an egg.

It’s important to note that IUDs don’t protect against sexually transmitted infections (STIs), so you should still use condoms to protect yourself and your partner during intercourse.

How does an IUD work?

Depending on the type you get, IUDs prevent pregnancy in one of two ways. The hormone-free Paragard IUD uses a small amount of copper—approximately 176 mg, per the FDA—to weaken sperm by creating an inhospitable environment in your uterus that isn’t sperm-friendly. Conversely, hormone-based Mirena, Kyleena, Liletta, and Skyla use progestin, an artificial hormone similar to progesterone, to thicken cervical mucus and even prevent ovulation, or the releasing of an egg from the ovary. Thicker mucus can block or trap sperm to prevent it from fertilizing an egg, and preventing ovulation means there’s no egg to fertilize to begin with.

Though Paragard, Mirena, and Liletta start working right away, you’ll want to wait at least 24 hours before having sex or inserting objects, such as tampons or sex toys, into your body. The same applies with Skyla and Kyleena, which take one week to become fully effective, unless insertion happens during the week following your period. (So remember to use a backup method of birth control for those seven days.) The copper Paragard can also be used as emergency contraception and is 99% effective at preventing unwanted pregnancy if implanted up to five days after having unprotected sex.

“The benefits of either type of IUD are that they are long-acting, reversible contraception and can be left in place for several years,” says Dr. Carolyn Ross, MD, OB-GYN, and Stix medical advisor.

What are the pros and cons of a hormonal IUD?

Two different IUD inserts.
Credit: Reviewed / Getty Images / Lalocracio

Both non-hormonal and hormonal IUDs contribute to pregnancy prevention within the uterus.

Hormonal IUDs are smaller than the copper option, making insertion somewhat easier. It’s typical to experience spotting for a few months after insertion, but after that, a hormonal IUD often makes periods lighter and less painful, and can even stop you from getting your period altogether, which could be beneficial for those who suffer from heavy, painful periods.

Like other methods of hormone-based birth control, hormonal IUD side effects may include acne, headaches, irregular bleeding, mood changes, and cramping. And because the progestin is localized to your uterus, any positive side effects, such as clearer skin or reduced unwanted hair growth, from previous birth control methods like the pill may subside.

What are the pros and cons of a copper IUD?

If you’ve had negative experiences with the pill or other types of hormonal contraception, the appeal of a copper IUD is almost undeniable. Effective for 12 years, it lasts the longest—a great bang for your pregnancy-prevention buck.

However, the extended protection might be overkill for anyone in the 40-plus crowd, and a progestin-emitting option may be more cost-effective for anyone (depending on your insurance), so chat with your OB-GYN about your family-planning options.

One of the biggest cons, though? Your monthly flow may be heavier and steadier. Copper IUDs can cause heavy periods and cramping, especially in the first six months. Though that typically improves with time—and periods may eventually end entirely while the IUD is in place—this can be a deal-breaker for new IUD users. If the intense side effects from a copper IUD don’t subside after six months, call your doctor to talk about your options.

Can you get pregnant with an IUD?

Yes, but the chances are extremely slim—less than 1%, to be exact. And because it’s a “set it and forget it” method of birth control, there’s no risk of using it incorrectly—no more having to set alarms to remember to take your birth control pill at the same time every day.

How long does an IUD last?

An IUD remains effective from three to 12 years, depending on the makeup or dose of hormone used. With an effectiveness of 12 years, Paragard lasts the longest, while Mirena and Liletta work for seven, Kyleena for five, and Skyla for three.

While even three years might seem like an eternity for anyone who suspects their desire to get pregnant may change, you don’t need to leave yours in the entire time to make it worth your while. And your ability to conceive returns almost immediately with removal.

How much do IUDs cost?

Depending on your insurance or lack thereof, the price of an IUD can range anywhere from $0 to $1,300, but usually there is no cost, thanks to the Affordable Care Act’s birth control mandate. Most insurance plans cover all forms of birth control, including IUDs, but they may only cover certain brands, so check with your insurance provider to see what options are available. If you don’t have insurance, you won’t automatically pay over a grand—visiting a Title X clinic such as Planned Parenthood can help reduce the cost.

What is the IUD insertion and removal process like?

Animated graphic of uterus.
Credit: Reviewed / Getty Images / Uffoow

Normal sensations after IUD insertion are cramping, slight lower back pain, and even some light bleeding.

Unlike most other forms of birth control, you must get your IUD placed and removed at your doctor’s office. During the insertion, your doctor or nurse will use a speculum to open your cervix and place the IUD in your uterus. You may receive medicine to help soften your cervix and be advised to take over-the-counter painkillers like ibuprofen ahead of your appointment. The process usually takes less than five minutes, and patients typically report cramping during the procedure, the severity of which can vary from person to person, according to Dr. Ross.

If you’re nervous about feeling lightheaded or dizzy after insertion, ask your partner or a trusted friend or family member to come with you so they may drive you home. It’s normal to experience cramping throughout the day following an IUD insertion—a good heating pad and some ibuprofen can help alleviate this.

After getting your IUD placed, you’ll be able to feel the strings poking out of your cervix into the top of your vagina with your fingers. Your doctor may recommend feeling for—but not pulling on—those strings once a month to make sure the IUD hasn’t slipped or moved. This is a rare occurrence, but can happen during the first three months following insertion.

The removal process is significantly easier. Your doctor will use forceps to clasp and pull on the IUD strings. As the IUD comes up against the cervix, the “arms” of the T-shaped device will fold up, and the IUD will slide out through the cervix and vagina. Patients may experience spotting after getting an IUD removed, and it may take a few months for your period to return to “normal”—but because your ability to get pregnant can return immediately, be aware that you’ll need to use another form of birth control right away if you’re not quite ready to conceive.

What are the general risks and side effects of having an IUD?

If you get pregnant with an IUD, you’re at higher risk for having an ectopic pregnancy, in which the fertilized egg attaches outside of the uterus, typically in the fallopian tube. However, because IUDs are so effective at preventing pregnancy, those with IUDs are at less risk for this than those who are sexually active but don’t use contraception.

Infection is possible from the insertion procedure, but rare. It’s also possible your body will reject your IUD and expel it—this is why it’s important to check on those IUD strings to make sure they haven’t moved. Expulsion is more likely if you’ve never been pregnant, have heavy or prolonged periods, have previously expelled an IUD, are younger than 20, or had your IUD inserted immediately after childbirth.

Additionally, because the IUD’s strings extend into the vagina, it can be risky to use most menstrual cups for period protection, as they can create a suction against the cervix, which could dislodge the IUD when the cup is removed. (Disc-style cups, like the Nixit, can be used instead, as they don’t suction in place.) The strings can also make sex uncomfortable for your partner initially, as they’re stiff after insertion but soften over time. If that doesn’t happen, schedule a follow-up visit with your doctor, who can trim the strings to make intercourse more comfortable.

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