13 Things You Need To Know About How Birth Control Works

You pop a birth control pill daily and then don’t think about it. Or, maybe you have an IUD inserted that you only spare a thought for when you silently thank it after amazing sex for keeping you child-free. But there’s so much to know about birth control—here’s what you should know.

1. Hormonal IUDs are pretty clever. They basically prevent sperm from reaching the egg by releasing levonorgestrel. This hormone also prevents ovaries from releasing eggs, but that’s not all. Hormonal IUDs also make cervical mucus thicker so sperm can’t get to the egg.
2. There are various types of IUDs available. We’re not just talking about different brand names here. Some hormonal IUDs release more or hormones than others. For example, Kyleena is an IUD that releases 17 micrograms of hormones daily, while Mirena releases 20.
3. IUDs aren’t one size fits all. Did you know that different IUDs have different sizes? If you’re worried about comfort, there are IUDs that are made with narrower inserters. These include brands like Skyla and Kyleena. This makes the process of getting an IUD much more comfortable.
4. All IUDs mess with your period. You can expect lighter, shorter periods when you have an IUD inserted. Or, you might stop getting periods altogether.
5. There’s also a copper IUD. This is basically an IUD that releases copper ions into your cervix instead of hormones (yay!). Copper is great at preventing pregnancy because it makes the cervix produce a thick mucus that sperm just can’t get through.
6. What about side effects? Hormonal IUDs can lead to irregular bleeding and PMS symptoms such as nausea, headaches, and pimples. Copper IUDs tend to have fewer symptoms because they don’t have hormones. That said, some women experience symptoms such as cramping and heavier or longer periods, which is especially a concern during the first few months of using the copper IUD.
7. Oral contraception is complicated too. You have many options available to you, such as the combined pill or progestin-only pill. The combined pill has both progestin and estrogen in it. It works by preventing ovulation hormones from forming. These are follicle-stimulating hormones and luteinizing hormones. The progestin pill, or mini pill, works by making cervical mucus thicker to prevent sperm from getting into the uterus.
8. Oral contraception has some important side effects. These include but are not limited to, nausea, breast tenderness, spotting between periods, weight gain, mood swings, and headaches.
9. There are other options if you forget to take your pills. If you’re the type of person who forgets, or simply doesn’t want, to take their birth control pills daily (which is obviously super important to prevent pregnancy), there are other options that work in the same way as oral contraception.
10. The birth control shot exists. This injection puts enough progestin in your body so that you’re protected against pregnancy for three months. It’s considered to be slightly more effective than the pill, but it can lead to more intense side effects.
11. Not into injections? You can get a birth control implant that releases progestin into your body for three years! It’s basically a thin rod that gets implanted underneath the skin of your upper arm. While it carries the same risk of side effects as other types of birth control mentioned above, its most common symptom is irregular bleeding, and this tends to happen within the first six to 12 months of use.
12. Some medication can tamper with how birth control works. If you’re taking birth control pills, St. John’s Wort can make it less effective. An antibiotic known as rifampin can also, but there are many other meds that can decrease how effective your birth control is. Interestingly, sometimes hormonal birth control can be the bad guy by interfering with other meds you’re taking, such as anti-seizure meds. This is why you need to chat to your doctor about any meds you’re on when you get prescribed hormonal birth control of any kind.
13. Other things can also get in the way of your birth control pill. Of course, missing a pill or taking it late is always something to avoid as it can prevent you staying child-free. But there are other things that can interfere with your body’s absorption of birth control. For example, if you have health conditions such as IBD or Crohn’s disease, this can prevent your body from correctly absorbing the pill (and any oral medication you take, FYI). And, if you’re having a bout of vomiting or diarrhea for two days or longer, it’s basically the same thing as missing a pill.