Plan B: How often can you take it & can you take it too much?

How often can you take Plan B?

Ever wondered, “how many Plan B can you take in a year”? Medical guidance suggests it’s safe to take Plan B as emergency contraception as often as you need too, even more than once per menstrual cycle. At the same time, Plan B isn’t considered as effective in preventing pregnancy compared to other certified birth control methods. Some women can also experience more side effects from emergency contraception, like Plan B, that are different from those associated with other hormonal birth control methods. These side effects are temporary, and current research shows no evidence of any serious complications or side effects associated with Plan B. [2]

If you find that you’re having to take Plan B frequently, it might be a sign that the birth control method you’re using isn’t a good fit for you. Or you might not currently be using any form of birth control. Using emergency contraception can be stressful, not only because you need to hurry and take it soon after sex, but also because of the wait to make sure it worked. Finding a birth control method that will work for you in the long term can better protect you from pregnancy. It can be helpful to speak with a nurse, doctors, or other healthcare professional to learn more about your options, aside from emergency contraception, and find one that suits you.

How effective is Plan B?

With emergency contraception, timing is important. Plan B, like other types of morning after pills, can prevent pregnancy but needs to be taken soon after unprotected sex (ideally within three days) [2,3]. If you’re worried about becoming pregnant, for example if a condom has broken or slipped off, or you’ve skipped a dose or two of your oral contraception, taking Plan B as soon as possible after having sex is the best way to maximize its effectiveness.

It’s important to note that Plan B isn’t 100% effective and it’s estimated that around 1-3% of women still get pregnant after taking an emergency contraceptive pill like Plan B. Plan B also isn’t designed to be used as a long term contraceptive, so it’s important to find a hormonal or non-hormonal alternative that you are happy using to make sure you’re properly protected. There’s also some research to suggest that being overweight or obese can impact the effectiveness of a pill like Plan B, so using another form of emergency contraception, like a copper IUD, might be recommended by your doctor [2].

How long does it take Plan B to work?

Plan B works by delaying your body from ovulating, thus preventing pregnancy. Plan B contains a synthetic (man-made) version of the hormone progesterone called levonorgestrel, which prevents the surge of luteinizing hormone that happens before you ovulate. If this LH surge has already happened, then Plan B might not work for you, which is why doctors advise taking Plan B as soon as possible after unprotected sex. Pills containing levonorgestrel, like Plan B, are most effective when taken within three days of sex, but in some instances can work up to five days. Ulipristal acetate can be taken up to five days after sex. [2,3,4] 

If you’ve had unprotected sex and are worried about the risk of pregnancy, it can be an anxious time as you work out what to do and in the waiting time before you get your period. It might be helpful to take a friend with you to the pharmacy or clinic to talk through your options and answer any questions. A pharmacist, nurse, or doctor can talk you through what to expect after taking emergency contraception and recommend any follow-up steps. Knowing all your options can help you decide the right outcome for you. 

Side effects of taking Plan B 

Generally speaking, Plan B and other emergency birth control pills are considered safe with no known serious complications or side effects even with repeated or longer-term use [2,3]. That said, they can cause short term side effects like [2]:

• Headache
• Nausea and/or vomiting
• Breast tenderness
• Abdominal pain
• Dizziness
• Fatigue

One of the most common side effects of taking Plan B is disruption to your regular menstrual cycle, which can change the length of your cycle or cause irregular bleeding or spotting for weeks or sometimes months [2,4]. It’s also important to note that if you throw up within two or three hours of taking Plan B, some medical professionals recommend repeating the dose [4].

Other things to consider when using Plan B frequently

Plan B, and other ECPs, can safely and reliably prevent pregnancy in emergency situations when you don’t use protection or if you’re worried another form of birth control (like a condom) failed. Levonorgestrel pills, like Plan B, are also accessible – they are available from most pharmacies and can be purchased or given without a prescription. At the same time, Plan B is not designed to be used long-term as birth control, and it's important to consider things like cost, menstrual cycle changes, and the effectiveness of other birth control methods if you’re taking Plan B frequently. 

Cost

Not only are there more effective forms of birth control, but also methods that are far more cost-effective than frequently taking Plan B. In the United States, Plan B can cost an average of $48 [4], while in Europe, the cost can range from $7 to $25 [5]. In the U.S., you might have to check your insurance coverage or check with an insurance provider if a prescription is needed. These considerations can make Plan B less available and less accessible for some women. 

Changes to your menstrual cycle

Menstrual cycle changes are the most common side effect of Plan B, and other forms of emergency contraception. These changes, and how long they last, can vary from person to person. They can also depend on when during your cycle you took Plan B. For example, some studies have shown that taking Plan B early in your cycle can shorten cycle length, while taking Plan B later in your cycle might have no impact on cycle length or might make your cycles longer. Plan B can also cause spotting or irregular bleeding between periods. [4]

Not as effective as some other emergency methods

While Plan B might be one of the more familiar types of emergency birth control, it’s actually not considered the most effective one out there. The other type of emergency contraceptive pill, ulipristal acetate, is considered more effective than Plan B, with pregnancy rates ranging from 0.9-2.1% (compared to 0.6-3.1% for levonorgestrel ECPs like Plan B). While Plan B doesn’t work if the luteinizing hormone surge has already begun, ulipristal acetate can still disrupt ovulation even after luteinizing hormone levels have begun rising. The copper IUD is also considered more effective as emergency birth control than pills, but it requires a doctor’s appointment. [3,4]

Plan B vs other types of emergency contraception

If you are looking to take emergency contraception to prevent pregnancy, it’s important to know that you have options. You can choose between taking a pill and getting the copper IUD fitted. If you opt for the pill option, there are two different types of pills: levonorgestrel and ulipristal acetate. Plan B is a common brand name of levonorgestrel, while ellaOne is a common brand of ulipristal acetate. In the U.S., brand name or generic levonorgestrel is generally available over-the-counter, while ulipristal acetate requires a prescription. Copper IUDs, on the other hand, are widely considered the most effective emergency contraception — and a great long term birth control option — but require visiting a clinician. [2,3,4]

Levonorgestrel and ulipristal acetate contain different active ingredients. Levonorgestrel contains a man-made hormone that acts like progesterone, known as progestin, while ulipristal acetate has an ingredient that blocks the effects of progesterone in your body. This is why ulipristal acetate can continue to prevent ovulation after the luteinizing hormone surge has started, but Plan B cannot delay ovulation once this process has already started. [4]

Recommendations on when to take levonorgestrel and ulipristal acetate are also slightly different. To be most effective, levonorgestrel pills like Plan B must be taken within three days of having unprotected sex, while ulipristal acetate can be taken within five days. The copper coil IUD is the most effective form of emergency contraception, up to 10 times more effective than emergency pills, and can also be fitted up to five days after having unprotected sex [3,4]. As emergency contraception, the copper IUD must be left in for three weeks, or it can be left in for up to 10 years if you wish to start using it as longer-term birth control. [2,3]

When to see a doctor

There aren’t any tests or checks needed after taking Plan B, but doctors generally advise taking a pregnancy test if you have not had your period within a week of when you would normally expect to get it. If you find out you are pregnant, it’s important to talk to your healthcare provider as soon as possible. They’ll be able to walk you through your options and advise on next steps. You might find it helpful to know that if you were already pregnant when you took Plan B, or became pregnant despite taking it, it hasn't been shown to impact the development of a pregnancy. Talk to your doctor to learn more. [2]

If you have taken Plan B or any other emergency contraception, do contact a healthcare provider if [3]: 

• You’re worried about any symptoms or side effects you’re experiencing 
• You might be pregnant, or have a positive result on a pregnancy test
• Your period is more than a week late
• You get your period, but it's shorter or lighter than what is normal for you, which can be a sign of pregnancy 
• You experience sudden or unexpected abdominal pain 

Know your non-fertile days and prevent pregnancy with Natural Cycles 

Did you know that there are only around six days each cycle when you can get pregnant? This is known as your fertile window, and knowing your fertile days is key to planning for or preventing pregnancy. This is where Natural Cycles comes in. Natural Cycles is the first FDA-cleared birth control app of its kind. It uses your biomarkers and cycle data to predict what days you are fertile each cycle. Each day, you’ll get a daily fertility status: Red or Green, letting you know when you need to use protection in order to avoid pregnancy and when you’re not fertile, so you don’t need to. Hormone-free, 93% effective with typical use,  find out how Natural Cycles can support you today.