When it comes to choosing a form birth control, there are lots of options to think about. There's the much buzzed about IUD (copper, hormonal); the permanent surgical kind (tube tying, vasectomy); the STD-safe latex kind (condoms); the "feels like it belongs in a different era" kind (diaphragm, cap, sponge); and of course there's the Pill and all its longer-lasting cousins (patch, rod, ring, shot). It's enough to make you want to lie down — and not in a sexy way!

Unfortunately, we don't have enough writers to dive into the pros and cons of each one. But, if you want to know more about those IUDs — aka intrauterine devices — we've got you covered. We sat down with Dr. Lexanne Mauney, Houston Methodist OB/GYN, to find out everything we ever wanted to know about IUDs. (Weirdly, a lot.) Here's what she had to say:

Q: What exactly is an IUD?

It's a small, plastic, T-shaped device that an OB/GYN provider places into your uterus to prevent pregnancy. It is approximately 1 inch in size, and it has thin wire strings that stay outside the uterus that allow us to easily remove it when the time comes. There are four hormonal kinds (Mirena, Skyla, Kileena, Liletta) and one copper kind (Paragard).

Q: How do they work?

All IUDs work by preventing sperm from reaching an egg, but the mechanism of action for the copper and hormonal devices are different. Paragard has copper wire coiled all around it. There are no hormones or medicines in it. The copper produces an inflammatory reaction that is toxic to sperm and eggs, preventing pregnancy for as long as it's in, which is up to 12 years.

Hormonal IUDs release a small amount of the hormone progestin. About 45% of women with hormonal IUDs won't get their period for months to years at a time. The remaining 55% of women will typically experience a lighter and shorter period while they have the device. Hormonal IUDs thicken the cervical mucus, which blocks and traps the sperm, preventing it from reaching an egg. In short, it turns the uterus into an environment that is not at all friendly for sperm. Mirena and Liletta are currently approved to work for seven years, Kileena for five and Skyla for three.

Q: How effective are they?

Incredibly. Hormonal IUDs are 99.8% effective and copper IUDs are 99.2% effective, whereas the Pill is somewhere around 91%-94% effective, depending on the study. IUDs (alongside subcutaneous birth control implants) are by far the most effective forms of reversible birth control on the market. You can "set it and forget it" for years, which is why the American College of Obstetrics and Gynecology recommends them as the first-choice contraception for women seeking birth control.

The 0.2% and 0.8% chance of pregnancy for hormonal and copper IUDS, respectively, comes from the small chance that the device might be expelled from your body. This happens in approximately 1% of patients, typically during the first six weeks after placement. Most people will notice that it has come out, but since it is so small and period-like clots are normal during that early adjustment period, theoretically it could come out without the patient realizing it. I ask all my patients to come in for a six-week check to ensure it has remained in place.

Q: How safe are they?

Again, incredibly. Expulsions are not health risks, only pregnancy risks. There is an extremely rare risk that the IUD could perforate the lining of the uterus. And while this is dangerous, especially if left untreated, it is much rarer than expulsion. The rate was less than 0.1% in a study of over 60,000 women. Otherwise, there are no known long-term health complications from IUDs.

Q: What are the benefits of hormonal IUDs?

As I mentioned, they can make your period lighter, shorter, less painful or even make it go away entirely. Most patients see that as a major benefit. It is an FDA-approved treatment for heavy menstrual bleeding.

It has also been shown to help prevent endometrial cancers and is actually used as a treatment for early-stage endometrial cancer, especially in women who would like to avoid hysterectomy in order to keep childbearing options open. Some other interesting studies have come out lately that show there may be a protective benefit against colon and ovarian cancers as well.

Another benefit is that you only need a small dose of hormone in order for the device to work. That's because it's placed locally, right in the uterus; it doesn't have to go through the digestive tract or blood stream like the birth control pill, shot or rod. This reduces the risks classically associated with hormonal birth control, including blood clots, breast lumps, mood effects and weight gain. Also, IUDs use progestin only, not estrogen, like most birth control pills. This makes them safer for breastfeeding moms to use because estrogen can affect breast milk supply.

Q: What are the benefits of copper IUDs?

Women who have had a hormone-mediated cancer and women who are prone to blood clots may do better without any hormones. A copper version gives them the effectiveness without any hormones. Another benefit of copper is that it lasts up to 12 years, making it by far the longest reversible option. They can be used as emergency contraception as well.

Q: Are there any negatives about IUDs?

The copper IUD can make your periods heavier and cause cramping, especially in the first six months. Some of my patients on hormonal IUDs complain of breast tenderness or mood effects, though this is fairly unusual.

For both types of IUDs, you may feel the device in the beginning. There will be some cramping and spotting for up to three months, and you may feel a twinge if you move or twist your core too suddenly. Some women have reported that their partner can feel the strings during sex, but the strings soften and curl in after a few months.

The experience of inserting the IUD can vary widely. Some women say they hardly feel it; others say it is very painful. This is probably because women's bodies, reproductive organs and pain tolerances aren't all the same. We like to place the device right after menstruation because the uterus is typically more open then and it goes in a little more easily. I tell my patients to take 800 mg of ibuprofen, unless they have a contraindication, and I've found that works really well. If you are worried about it, talk to your doctor about your concerns and your pain relief options. I recommend not letting the first minute of an IUD prevent you from enjoying the benefits for many years.

Q: Is it recommended for everyone? Does it matter if you've had kids or not, or want to have more kids?

It is for all women seeking birth control, no matter what stage of the reproductive journey they're in. There used to be an old-school belief that IUDs weren't for young women, or virgins, or women who want to have kids eventually. This has gone out the window. There are no lasting effects on your body or fertility; you can get pregnant immediately after removing the device. You can have it in between babies. You can have it if you never plan on having babies. As a woman and as an OB/GYN, hormonal IUDs are my No. 1 recommendation for birth control, because they're foolproof, make periods easier and have additional protective health benefits as well.