BIRTH CONTROL first (because I have to be a little less careful about how I explain everything):
From the beginning - birth control is anything that is designed to prevent a pregnancy. Some also prevent STIs (sexually transmitted infections), some do not. To see a full list of birth control options available in the US and some of the pros/cons, check out the CDC website. If you are considering a particular type of birth control, I'd definitely talk to your doctor about the pros/cons of each type and how that fits with your life.
Some factors to consider when choosing a form of birth control:
1. how much do you not want to be pregnant? as in, how good does your birth control method need to be? For example, if you are not willing to make some decisions about an actual pregnancy, the withdrawal method (where the penis is removed before ejaculation) is not a good method for you, because it's not very effective. On the other hand, IUDs are more effective than tubal ligation.
2. would you rather use something only at the time of sexual intercourse? OR
3. how good are you at remembering something consistently? If taken correctly, birth control pills are 98% effective, if taken incorrectly (like missing them, taking them at different times, taking other medications that interfere with them), they are only about 80% effective, meaning 1 in 5 women who takes them incorrectly gets pregnant.
4. how much money are you willing to spend on birth control? Many people like the hormonal ring because it can be put in for the whole month but is otherwise much like the birth control pill, but it's pretty expensive. On the other hand, condom charges can add up pretty fast. An IUD is expensive up front, but then you don't have to pay anything for the next 5-10 years.
5. is there any reason why you shouldn't use a particular type of birth control? do you have a clotting disorder in your family or a family history of breast cancer? then maybe birth control involving estrogen is not the best for you. If you have a male partner who refuses to wear condoms, well - THAT's not going to work (also, probably worth a conversation about why)
6. Is there an added benefit to using any type of birth control? for example, estrogen-containing pills often also help clear up skin, the progesterone-secreting IUD can make your periods lighter.
7. Do you need to get period every month? Or do you NOT want to get a period every month? depending on your own neuroses, it might be important that you see "proof" that you're not pregnant every month. On the other hand, menstruation might really interfere with your day to day life. Hormonal methods like the pill, the patch, and the ring allow for you to choose if you want to have a withdrawal (of progesterone) bleed, whereas with the progesterone IUD (the Mirena), 1/5 of women stop bleeding altogether.
8. What kind of access do you have? If your job takes you traveling all over the world, you might not be able to get your pills refilled every month. Depending on where you are, it's easier or harder to undergo any procedural birth control like tubal ligation (tubes tied), vasectomy (where the male vas deferens or the tube the sperm swim from the testes to the penis in, gets cut), or even IUD placement (though this is much more widely available).
9. What do you like? If you really don't like the feeling of anything in your vagina, the ring might not be the best option for you. If you're not into condoms, chances are, you won't use them or they'll make sex less enjoyable. If you hate trying to remember your pills, they aren't the best option for you.
10. What does your partner like (or rather, not mind)? male condoms definitely require some male partner consent, especially if he's going to be buying them. There are also those wonderful male partners that help pay for birth control pills or IUDs because he knows he's benefiting too. But there are also male partners who can feel the IUD strings so are less wild about those. Definitely a factor to consider, but I put it last for a reason. YOU are the person who should feel comfortable with your birth control because you are the one who will be pregnant if it doesn't work out.
My one plug is that recently a lot of my classmates have gotten IUDs because with night call and 24 hour shifts and generally unpredictable schedules, not to mention moving around, it became harder to remember any type of birth control (pills, patches, rings). Generally, people are very satisfied - less bleeding, no estrogen meaning no water weight but also no acne control, and best of all: no having to think about it.
The most important thing about a birth control option is that it works for your lifestyle because none are good if not actually used.
"Birth control is a woman's right to decide when she is ready to be a mother"
"I got a pocket full of rubbers and my homeboys do too"
-Snoop Dogg, in his song Gin and Juice
promoting the use of safe birth control methods