Plan B, also known as the morning after pill, is an emergency contraceptive that can help prevent pregnancy after unprotected sex or birth control failure. It is most effective when taken within 72 hours of unprotected sex.
It works by preventing ovulation so that an egg can’t be fertilized by sperm. It can also affect the timing of your period, though many people don’t experience any symptoms.
What is Plan B?
Plan B is a pill that’s taken orally to prevent pregnancy. It contains the hormone levonorgestrel and is also known as the morning-after pill or emergency contraceptive. It’s FDA-approved and is available over the counter with no age restrictions. It’s best used within 72 hours after unprotected sex or when other forms of birth control fail.
It works by temporarily stopping your body from ovulating (releasing an egg). That means no fertilized eggs can implant in the uterus, so pregnancy is impossible. Plan B and other emergency contraceptives don’t protect against sexually transmitted infections, so it’s not a replacement for primary methods of birth control like condoms, rings, or pills.
The medication starts working soon after you take it. Peak levels of the drug in your bloodstream occur about 1.7 hours after you take it. If you’re near ovulation or are heavier than about 155 pounds, it may not work as well for you. It’s also less effective if you have unprotected sex right after taking it.
Some women who regularly use EC experience irregular periods, as it can affect the timing of their menstrual cycle. So, if you’re planning on using Plan B for a long period of time, it’s a good idea to switch to a regular method of birth control later on. That way, you’ll always have a reliable form of protection to fall back on in case something happens unexpectedly.
How does Plan B work?
Plan B (levonorgestrel) is a morning-after pill that can help prevent pregnancy when used within 72 hours after unprotected sex or birth control failure, like if a condom breaks or a missed dose of your regular birth control. It works by temporarily delaying ovulation, so that if an egg is released before Plan B is taken, it’s unlikely to be fertilized. The emergency contraceptive can also make it more difficult for sperm to reach and fertilize an egg, and may even stop the fertilized egg from attaching to the uterus.
Having sex shortly after taking Plan B can still lead to pregnancy, though, because the levonorgestrel is likely to leave your system in a week or so, Gariepy says. Plus, it’s not effective if you take it after ovulation has already happened, and certain medications, like seizure medicines, can interfere with how well it works.
Another thing to keep in mind is that Plan B doesn’t protect against sexually transmitted infections, including HIV/AIDS and genital herpes. So, if you’re thinking of having sex after using the medication, it’s best to use a condom or diaphragm instead. And if you end up throwing up after taking Plan B, that’s a sign that your body hasn’t absorbed all the medicine, so it’s important to get it back into your system as soon as possible.
What are the side effects of Plan B?
There are a few side effects that are pretty common when taking Plan B, including pelvic pain and changes to your menstrual cycle. However, these shouldn’t be extreme or severe. It’s also important to note that Plan B does not protect against sexually transmitted infections, so if you want protection for HIV/AIDS, genital herpes, chlamydia, or hepatitis, use latex condoms and practice abstinence.
It’s a good idea to keep Plan B in your medicine cabinet so you can grab it if the occasion arises. And, as always, be sure to check the labels of any nonprescription or prescription medicines you’re taking, because some can affect how well Plan B works.
The sooner you take Plan B after unprotected sex, the better. The pill works by thinning the uterine lining, so it’s less effective if you wait longer than 72 hours. And, remember that it’s not as effective for people who are near ovulation or who have a higher body mass index (BMI).
Plan B doesn’t interact with most medications, but if you’re taking certain ones—including antibiotics, antifungals like griseofulvin and St. John’s wort, some HIV medicines, and some anti-seizure drugs—it can reduce how well it works. And, as with any medication, it’s best to talk to your doctor if you have any questions or concerns. They can advise you on the right dosage and timing for you.
Can I get pregnant while taking Plan B?
Using Plan B does not affect future fertility, according to the World Health Organization. This is because the hormones that make it work leave the body in a few days. This means that women can become pregnant from any sexual contact in the future. However, a woman should not use Plan B as her primary form of birth control because it isn’t as effective as other methods.
When used correctly, the pill is up to 97% effective in preventing pregnancy. It works by temporarily delaying ovulation, so the egg isn’t there to meet sperm. However, it is less effective the longer you wait to take it. If you want to be sure that it is going to work, it’s best to take it within three days of unprotected sex.
It is important to note that using Plan B does not protect against sexually transmitted diseases like hepatitis, herpes, or chlamydia. These diseases can only be prevented by using a primary method of birth control, such as the pill, IUDs, implants, shots, condoms, or latex condoms.
It’s also important to remember that Plan B is only 89% effective if it’s taken within 72 hours of unprotected sex. If you’re close to ovulation, or taking certain medications (like seizure drugs), it may not be as effective. Additionally, if your period is more than a week late after taking Plan B, you should consider a home pregnancy test.