How Often Can You Take Plan B?

Plan B is often used as a term for a back-up plan, something you turn to when your initial idea doesn’t quite work out. However, Plan B is also widely known as the name of an over-the-counter emergency contraceptive.

Designed to be taken within three days of unprotected or under-protected intercourse, Plan B and (most) other emergency contraceptives utilize a high dose of a progestin hormone (called levonorgestrel) to prevent any sperm from fertilizing an egg. “Essentially, that dose of progestin signals to your body that you’re pregnant,” explains women’s health specialist Sophia Yen, M.D.,a clinical associate professor at the Teen and Young Adult Clinic at Stanford Children’s Health in Sunnyvale, CA. This, in turn, prevents ovulation from taking place, she explains, which keeps an egg from releasing from the ovaries to the fallopian tubes if it has not already.

The levonorgestrel dose in the morning after pill also increases the viscosity of the mucus in the cervix, which slows down sperm and also decreases the likelihood that an already-fertilized egg implants in the uterus (thus preventing pregnancy), she explains.

While Plan B is not birth control and should not be utilized as such, it is safe to take as many times as you need within a single menstrual cycle, as well as over the course of your life, says Dr. Yen. That’s right: There are no major long- or short-term consequences to using Plan B or any other form of emergency contraceptive multiple times. Get the details, below.

“There is no specific limit on the number of times Plan B can be taken,” says obstetrician and gynecologist Tiffany Pham, M.D., an OB/GYN at John Muir Health in Orinda, CA, and medical advisor at fertility and ovulation tracking app Flo Health. Plan B is a synthetic form of progesterone, which has multiple medical applications including hormone therapy, contraception, and abnormal uterine bleeding. To date, no long-term health consequences have been identified as being associated with taking emergency contraceptive multiple times. Meaning, people can take it as often as they need to prevent unwanted pregnancy following unprotected or under-protected intercourse.

Still, healthcare experts advise against using emergency contraceptives like Plan B as a regular form of birth control. “It should only be used as a secondary prevention measure in the event of failure of a primary prevention measure,” says Dr. Pham. For example: After a condom breaks, a failed pull-out attempt, or upon realizing you weren’t consistent with your birth control pill ingestion, she says. In other words, it is back-up birth control, not birth control itself. There are a few reasons why.

First, taking Plan B after unprotected intercourse is actually less effective at preventing unwanted pregnancy than other forms of contraceptive. “Depending on where you are in your menstrual cycle and how soon you take it following intercourse, Plan B is 58% to 95% effective at preventing pregnancy,” says Dr. Yen. Meanwhile, birth control methods like the birth control pill, hormonal or non-hormonal intrauterine device (IUD), implant, shot, ring, and patch are all up to 99% effective when administered correctly. (Don’t NOT use Plan B though: If taken in the 24 hours after intercourse, it is 95% effective, which is about the same as your birth control pill.)

Second, Plan B floods the body with a high-dose progestin that keeps the body from ovulating, which is an essential phase in the natural menstrual cycle. Missing ovulation a few times over the course of your life as a result of Plan B ingestion is no big deal. But regular ingestion will mess up your body’s natural monthly rhythm.

Your menstrual cycle and changes to your menstrual cycle can help identify other health concerns such as STIs, hormone imbalances, thyroid issues, and more, says Dr. Yen. By regularly taking Plan B, you “turn off” this vital sign, and interfere with your ability to read and interpret what your natural menstrual cycle is telling you.

Plan B is a single-dose tablet that contains 1.5mg of levonorgestrel. Similar brand name emergency contraceptives—like Take Action, My Way, Option 2, Preventeza, AfterPill, My Choice, Aftera, and EContra—also contain the same amount of levonorgestrel (1.5mg).

If you are taking emergency contraceptives, you should only take one dose of the medication at a time. Taking more than the recommended dose at once can disrupt your hormonal balance and cause adverse effects.

Something to keep in mind: Plan B and other emergency contraceptives containing levonorgestrel work best for individuals with a body mass index (BMI) of 25 or below. They are not effective for those with BMIs higher than 30, says Dr. Yen. What about doubling the dose? A 2022 study published in the journal Obstetrics & Gynecology found that doubling the dosage of Plan B (or its generic versions) did not make it any more effective for individuals with higher BMIs.

If you have a higher BMI, Dr. Yen suggests considering an alternative emergency contraceptive called Ella. Each prescription tablet contains 30 milligrams of ulipristal acetate, which is an ingredient that postpones ovulation, and remains effective for individuals with a BMI of up to 35.

Another highly effective option for folks of any BMI is to have a copper IUD (ParaGard) implanted, says Kara McElligott. M.D., an obstetrician-gynecologist in Durham, NC. “When placed in the uterus within five days of penis-in-vagina sex, it can reduce the chance of pregnancy by up to 99%,” she says. Once inserted, the copper ions in the IUD impair the vitality and function of any sperm inside the reproductive tract. Meanwhile, “the IUD makes the endometrial lining unreceptive to implantation, therefore reducing the risk of pregnancy after intercourse,” she explains.

No matter what emergency contraceptive you opt for, it’s important to follow the instructions on the product label, or those given to you specifically by your healthcare provider.

Plan B has not been linked with any long term or serious side effect, according to research published in Clinical Obstetrics and Gynecology.

However, taking Plan B may result in any of the following short-term side effects, and taking too much Plan B can amplify these side effects:

• breast tenderness

• cramps, stomach

• dizziness

• fatigue

• headache

• irregular bleeding

• vomiting

The most common side effect of taking Plan B is an out-of-whack menstrual cycle, says Dr. Yen. “After you take Plan B, your period might come on time, late, or early,” she says. This might also involve heavier or lighter bleeding or spotting between periods. If you don’t get a regular period within four weeks of taking Plan B, she recommends taking a pregnancy test.

The side effects of taking Plan B are both mild and short-term. Typically, the side effects will resolve within a couple of days of taking it, says Dr. Yen. Irregular bleeding can last up to a couple of weeks.

If you are experiencing the side effects for longer than that, she recommends consulting with a health care provider, as the side effects of Plan B—like fatigue and vomiting—are similar to the symptoms of early pregnancy.

“Yes, you can take a levonorgestrel emergency contraceptive twice in the same menstrual cycle,” says Mary Jane Minkin, M.D., an obstetrician and gynecologist at Yale-New Haven Hospital in New Haven, CT. It is also safe to take it during back-to-back months, she says. “There is no limit to how many times you can take it.”

That said, taking additional doses of Plan B after the initial dose will not decrease your risk of getting pregnant any more than taking a single dose will. The only reason to take Plan B a second (or third) time is because you have had intercourse without using a form of contraception for a second (or third) time.

In the event that you need to take emergency contraception for a second time during a menstrual cycle, Kameelah Phillips, M.D., a board-certified obstetrician/gynecologist at Calla Women’s Health in New York City, recommends consulting with your healthcare provider to come-up with an ongoing plan for contraception. That’s because the consequence of exclusively relying on Plan B to prevent unwanted pregnancy multiple times is that you are more likely to become pregnant than you would if you were regularly using contraceptives, she says. (Again, preventing unwanted pregnancy is most effective when you regularly use long-lasting birth control, like the intrauterine system (IUS), IUD, or contraceptive implant).

Worth mentioning: If you don’t currently have a long-lasting hormonal birth control implant, are not taking another form of birth control, and do not plan to use a barrier in days after you took Plan B the first time, you should consider getting an IUD inserted, says Cristin Hackel, MSN, a registered nurse practitioner in Bethesda, MD, and the medical director at Nurx, a telemedicine company that offers birth control, emergency contraception, and other sexual health treatments and tests.

“When inserted within five days of unprotected intercourse, the copper IUD lowers your chances of getting pregnant by more than 99.9%,” she says. Plus, it acts as a long-acting form of birth control that, upon insertion, immediately protects you against unwanted pregnancy in the future. (Other forms of birth control, like the pill, patch, ring, and injection can take up to 30 days to be effective, says Dr. McElligott).

Birth control and emergency contraceptives may both work to help you prevent unwanted pregnancy, but they are not interchangeable and have different utilities. While birth control is proactively used or taken ahead of intercourse to prevent unwanted pregnancy, Plan B is taken retroactively as soon as possible after intercourse to help prevent fertilization and implantation following intercourse, explains Dr. Pham.

When should you opt for one over the other? As an emergency contraceptive, Plan B is made to be taken during, well, emergencies, says Dr. Yen. You might take Plan B, for example, if you forgot to use a barrier method, there was a user error or mishap (like breakage), or during extenuating circumstances, such as sexual assault, she says. You might also take emergency contraceptives if, prior to sex, you did not properly take your birth control method, according to Dr. Phillips. For example, if you forget to take several birth control pills that month, or are late on re-upping your birth control shop, she says.

If, however, you are looking for a regular and/or long-term pregnancy prevention option, you’d be wise to consider birth control over emergency contraceptives, says Dr. Yen, as birth control is more effective at protecting against unwanted pregnancy.

There is a wide array of birth control options available including hormonal and non-hormonal, short-acting and long-acting, as well as temporary and permanent options, says Dr. Phillips. Here’s a look at some of these birth control options.

Birth Control Pill

Birth control pills work by releasing some dose of estrogen, progesterone, or a combination of both into the body following oral ingestion. “There are dozens of birth control pill options on the market, but they all need to be taken every day to work well,” says Dr. Minkin. Thus, it’s important to be realistic about whether or not you can commit to taking a pill at the same time every day prior to selecting this option.

• Effectiveness: Up to 93%

• Prescription needed: Sometimes

• Available over the counter: Sometimes

• Available online: Yes

• When effective: After 30 days

IUD

An IUD is a long-acting reversible contraceptive (LARC) that gets surgically inserted into the uterus by a healthcare provider, where it effectively prevents unwanted pregnancy for three to 10 years depending on the type. Or, until it is removed. There are two types of IUD: hormonal and copper. Which you opt for will depend on comfort with using hormonal options, as well as whether or not you are also using it as an immediate emergency contraceptive.

Given that the effectiveness of other methods like the birth control pill vary based on how consistently and correctly the method is used. Dr. Phillips recommends an IUD for those who suspect they will be prone to miss the pill or are otherwise seeking a form of contraception that they don’t have to take or insert often.

• Effectiveness: Up to 99%

• Prescription needed: Yes

• Available over the counter: No

• Available online: No

• When effective: Immediately

Birth Control Implant

Another form of long-lasting reversible contraceptive, the birth control implant involves getting a small, thin rod (the Nexplanon or Implanon) surgically inserted into the upper arm. There, the rod slowly releases a small dose of synthetic progesterone into the bloodstream which thickens the cervical mucus in such a way that sperm cannot travel through to the uterus. This option will work for three years prior to needing replacement.

• Effectiveness: Up to 99%

• Prescription needed: Yes

• Available over the counter: No

• Available online: No

• When effective: Depends, but usually after one week

Birth Control Shot

The birth control shot, also known as a Depo-Provera shot, involves receiving a progestin injection into the arm or buttocks by a healthcare provider every three months. In order to be effective, you need to commit to getting it on schedule, says Dr. McElligott who recommends considering whether or not that is logistically possible for you prior to selecting this option.

• Effectiveness: Up to 96%

• Prescription needed: Yes

• Available over the counter: No

• Available online: No

• When effective: Depends, but usually after seven to 10 days

Birth Control Patch

Using the birth control patch involves wearing a transdermal patch on the stomach, back, or arm, where it goes to work releasing a low-dose of estrogen and progestin, which prevent ovulation, through the skin and into your bloodstream to prevent pregnancy, explains Dr. Pham.

The patch requires some user-diligence, as a new patch needs to be applied each week. Plus, users need to check daily to make sure that the entire patch is sticking to their skin and not peeling away.

• Effectiveness: Up to 93%

• Prescription needed: Yes

• Available over the counter: No

• Available online: Yes

• When effective: Depends, but usually after one week

Vaginal Ring

The vaginal ring, which is also known by its brand name the NuvaRing, is a small, flexible ring that is manually inserted into the far back of the vaginal canal. There, it releases hormones (estrogen and progesterone) that prevent pregnancy.

Each ring is designed to be inserted and left for three weeks, before it gets removed and thrown out. Users remain ring-free for seven days, during which they will often have a period, prior to inserting a brand-new ring.

• Effectiveness: Up to 93%

• Prescription needed: Yes

• Available over the counter: No

• Available online: Yes

• When effective: Depends, but usually after one week

Condoms

Condoms are a barrier-based birth control method that create a thin barrier between the penis and vagina during intercourse, which ultimately keeps sperm from entering the vagina altogether.

There are external condoms (also known as male condoms) that are worn by the person with the penis, as well as internal condoms (also known as female condoms) which are inserted into the vaginal canal ahead of play.

• Effectiveness: Up to 95% with proper use

• Prescription needed: No

• Available over the counter: Yes

• Available online: Yes

• When effective: Immediately

Fertility Awareness Methods

Fertility Awareness Methods (FAMs) involve tracking the menstrual cycle in order to predict when the ovulation window (aka fertile window) is through a paper calendar or app, or through tracking vaginal mucus or basal body temperature. The idea is that individuals who do not wish to become pregnant can avoid intercourse altogether during their fertility window, or opt for another form of birth control (like condoms) during that time. These methods are generally far less effective than other birth control methods highlighted above.

• Effectiveness: Up to 76% to 88%

• Prescription needed: No

• Available over the counter: N/A

• Available online: N/A

• When effective: Depends, but usually after 3 months of tracking

Other Non-hormonal Birth Control Methods

• Effectiveness: Up to 71% to 95%

• Prescription needed: Sometimes

• Available over the counter: Usually, yes

• Available online: Yes

• When effective: Immediately

The copper IUD may be one non-hormonal method, but it is not your only non-hormonal birth control option.

These options include:

• Diaphragm (like Caya)

• Cervical cap

• Sponge

• Spermicidal gel

• Phexxi birth control gel

• Internal condom

• External condom

• Fertility awareness methods

The exact mechanism these birth control methods use to prevent pregnancy vary product-to-product. Some, like the diaphragm, and internal and external condom, create a physical barrier between the sperm and the (potential) egg. Meanwhile, contraceptive and spermicidal gels create an inhospitable environment for the sperm.

With so many forms of birth control available, figuring out which is best for you can be overwhelming. When selecting a type of contraception, Dr. Phillips suggests considering your life stage (aka how soon you’ll want to become pregnant, if at all) and personal health background. “You should also think about what they want out of a birth control option, including effectiveness, safety profile, availability, cost, and frequency of administration, among other things,” she says. It is also important to note that some formulations containing estrogen will not be recommend for certain conditions (such as migraines with aura, smoking, high blood pressure, breast cancer) due to higher stroke risk.

Your gynecological or other healthcare practitioner can help you weed through the options and select the one that makes the most sense for you and your body, says Dr. Minkin. If you don’t have a PCP, she suggests going to your nearest Planned Parenthood for guidance.

Over-the-counter Plan B, when taken as prescribed, is an effective way to reduce your risk of unwanted pregnancy. Its effectiveness remains no matter how many times you have it, and it comes with very few unwanted short-term side effects, and no long-term risks.

However, since taking Plan B retroactively (or after having sex) is less effective at preventing unwanted pregnancy than taking birth control proactively (before sex), Dr. Yen recommends talking to your doctor for personalized guidance and information on all the various contraception options available.