Also known as the "set and forget" birth control method, intrauterine devices (IUDs) are T-shaped devices inserted into your uterus to prevent pregnancy. They do this with nearly 99% effectiveness.

IUDs come in two different types: hormonal and non-hormonal. Depending on the type of IUD, they can last anywhere from three to 10 years.

Northwestern Medicine OB-GYN Kristen Rose Venuti, MD, answers frequently asked questions about IUDs.

Does it hurt to get an IUD?

Because the IUD is inserted into your uterus through your cervix, which is narrow and contracted, you may experience discomfort or even pain during the procedure. However, the procedure is quick. Your clinician may be able to insert as quickly as you can cough. There are various methods that can help with the pain. For example, your clinician may provide you with a cervical softener prior to insertion to help the muscles around your cervix relax for easier implantation. Your clinician may also recommend taking over-the-counter pain medication before you arrive at the office.

How do hormonal IUDs work?

Hormonal IUDs are plastic devices inserted into your uterus that release levonorgestrel, a hormone that prevents pregnancy by:

• Thickening the mucus of the cervix, which stops sperm from travelling into the uterus
• Thinning the lining of the uterus so an egg can't implant on it
• Sometimes reducing the monthly release of an egg, called ovulation

Hormonal IUDs can last up to eight years, depending on which type you choose. Different types have different amounts of hormones in them.

How do non-hormonal IUDs work?

Non-hormonal IUDs are made of copper, which is toxic to sperm. Copper IUDs can last up to 10 years and there is only one type currently available.

Will I still get my period on an IUD?

Hormonal IUDs can drastically reduce your period. Some people may not get a period at all while on hormonal IUDs, which is why they may be prescribed for menorrhagia (heavy menstrual bleeding) or dysmenorrhea (painful periods).

Typically, you will still get your period if you have a non-hormonal IUD. Three to six months after getting a non-hormonal IUD, you may have a heavier period, but it will typically return to your pre-IUD normal."

Can you use IUDs for emergency contraception?

Yes. If you get one within five days after having unprotected sex, both types of IUDs work as emergency contraception.

Can you feel your IUD inside of you?

Some people may report feeling their IUD during sexual intercourse, but typically you will not notice or feel it.

How do you know if your IUD moved?

Your IUD has strings on the end. You will not notice or feel these strings, but if you do a self-examination of your cervix, you can typically feel for the strings. A clinician can check for these too, and they typically will at your yearly OB-GYN visit.

Your clinician will ask you to come back a few weeks after the insertion to ensure that your IUD is in the correct place. They may do check this with a pelvic exam or through an intrauterine ultrasound.

It is very uncommon (1 in 1,000) for your IUD to cause perforation, or tearing of your uterus. It is also very uncommon for your IUD to become embedded (grow into) the lining of your uterus.

Do IUDs cause infertility?

IUDs do not cause infertility. While it may take a bit of time to get pregnant after you stop taking birth control pills, you can get pregnant as soon as your IUD is removed.

Which option is right for me?