context: If you're thinking about using emergency contraception, you may wonder: What will I feel like afterward? The pill forms are safe. That's why you can buy some of them without a prescription. They contain the same hormones that are in birth control pills, which women have been using for decades. The copper- T IUD (intrauterine device) is also a very effective, safe way to prevent a pregnancy after sex. Research shows that Plan B One- Step starts to lose its effectiveness in women heavier than 165 pounds. It's not recommend for anyone over this weight -- instead, a copper- T IUD is the suggested option. Most women don't have any side effects after they use emergency contraception. But if you do, they should be mild and go away quickly. There are no long-term effects either. Different pills are available -- brands as well as generics. There are 3 types of emergency contraception in pill form that are sold both with and without a prescription. You need to be 17 to buy them if a prescription is needed. Depending on the brand and dose, you might get 1 pill or 2. Pills containing a hormone called levonorgestrel: My Way (over-the-counter) Plan B One- Step (over-the-counter) Preventeza (over-the-counter) Take Action (over-the-counter) Birth control pills can also be used as emergency contraception, but you have to take more than one pill at a time to keep from getting pregnant. This approach works, but it is less effective and more likely to cause nausea than levonorgestrel. Birth control pills require a prescription. Talk to your doctor or nurse to make sure you are taking the correct pills and dose. A third kind of emergency contraception pill is called ulipristal (ella, ella One). You need a prescription to get it. The side effects for these medications are similar and usually last a day or two at most. They may include: Belly pain and cramping Breast tenderness Dizziness Feeling tired Headache Upset stomach and vomiting Later, you may have a few others: Spotting. Within the next week, you might have some spotting. Your next period may also be lighter or heavier than you're used to. It's common and not something to worry about. But if you're concerned or the bleeding seems very heavy, call your doctor. Changes to your cycle. Emergency contraception can cause your next period to come a bit early or a bit late. That's normal. But if you're more than a week late, you should take a pregnancy test. If you have severe belly pain, you should call your doctor right away. This could be a sign of a tubal, or ectopic, pregnancy. This is a medical emergency. If you have other symptoms that concern you, call a doctor or pharmacist to be safe. The copper- T IUD ( Para Gard) is a small T-shaped piece of plastic and copper that can be used as both emergency contraception and as ongoing birth control. To use it for emergency contraception, a doctor or other health professional needs to insert it in your uterus within 5 days of when you had sex. The procedure may feel like a Pap smear. It will be uncomfortable -- like mild cramps -- but it takes only a few minutes. Once it's in, you won't be able to feel it. Your doctor will show you how to check that it's still in position once a month. You just have to feel for a string that extends into your vagina. After you have the IUD, you may have heavier periods with more cramping than before. Other side effects are uncommon. Rarely, the device may fall out of position. IUDs also pose a very small risk of infections or damaging your uterus. The copper IUD is the most effective form of emergency contraception. If you have a headache or are cramping, try a nonprescription painkiller like ibuprofen or naproxen for a day or two. The most common side effect of the pill forms is upset stomach. About 1 out of 5 women taking Ella, Plan B One- Step, and generics -- such as My Way -- feel queasy. Some throw up. Higher doses of regular birth control pills, which some doctors also use for emergency contraception, are the most likely to upset your stomach. What can you do for nausea? Eat smaller but more frequent meals. It might help to suck on sugar-free hard candy, too. If your nausea or vomiting is severe, call your doctor. Taking medicine to calm your stomach for a day or two could help. If you throw up within a couple of hours of taking the pill, you should take another dose. You probably need to take anti-nausea medicine first. Check with your doctor. If you have any side effects, they should be gone in a day or two. You don't have to call a doctor after using emergency contraception, but if you have questions or anything worries you, go ahead. You don't need any routine follow-up exam or tests. If your next period is more than a week late, you should take a pregnancy test. The copper- T IUD works as regular, ongoing birth control. Many women who use it for emergency contraception keep it in. It can prevent pregnancy for up to 10 years. If you decide you want to get pregnant, a doctor will remove it. After it's out, the IUD will have no lasting effects.