Does Plan B One Step work during ovulation?

No, Plan B One Step won’t work if you have already started ovulating because it works by temporarily stopping ovulation (when your ovary releases an egg for fertilization from sperm). Emergency contraception must be used before a pregnancy occurs. Plan B One Step will not end a pregnancy that has already started when a fertilized egg has implanted on the uterus.

It’s best to use the emergency contraception pill as soon as possible, but within 3 days (72 hours) of having unprotected sex. It works best when used as soon as possible, so do not delay.

Emergency contraception like Plan B One Step (levonorgestrel 1.5 mg) is safe and has been used over 30 years. There have been no reports of serious complications. It won’t impact your ability to get pregnant in the future.

Intrauterine devices (IUDs) and ulipristal (Ella) are other emergency contraception options.

• The copper IUD is the most effective form of emergency contraception and can be used up to 5 days after unprotected sex. It is inserted by a doctor and is up to 99% effective. It is more expensive than the morning after pill but can be left in place for up to 10 years as long-term birth control.
• Ella (ulipristal) is another type of emergency contraceptive pill that can be taken up to 5 days after unprotected sex, but it requires a prescription.

How can I tell if I am ovulating?

Determining exactly when you are ovulating can be difficult, and regular birth control is the most reliable way to prevent pregnancy on a month to month basis. Some people may track their ovulation in order to help increase their changes for fertilization and pregnancy. Using ovulation as a method of birth control is not very reliable.

You can estimate the time period during which you may be ovulating in several ways. Using a combination of these methods may be most effective.

• If your cycle, ovulation typically occurs 12 to 16 days before your period starts. The menstrual cycle is the time from the first day of your period to the day before your next period. You can track your menstrual cycle and estimate the days that you may be ovulating. The length of a menstrual cycle can vary, but on average are 28 days long, but can range from 23 to 35 days. You may find it helpful to track your cycle on paper or on an app on your phone for several months.
• You can monitor your basal body temperature (BBT) with a basal or digital thermometer. Your body temperature drops slightly right before an egg is released from the ovary, and rises 24 hours after the egg is released and stays elevated for several days. Before ovulation, your basal body temperature averages between 97 °F and 97.5 °F (36.1 °C to 36.4 °C). After ovulation, it rises to between 97.6 °F to 98.6 °F (36.4 °C to 37 °C).
• An ovulation predictor kit, which can be bought at most pharmacies, can also be used to track ovulation.
• You may notice that your cervical mucus may change in consistency (more wet or clear around the time of ovulation).

Sperm typically live for up to 5 days in the reproductive tract and an egg is usually viable for 12 to 24 hours after it’s released. If an egg is not fertilized in this time frame, it will be reabsorbed by the body and no pregnancy will occur.

Learn More: Video: How does ovulation occur?

What is Plan B One Step?

Plan B One Step (levonorgestrel 1.5 mg) is an emergency contraception pill. It can be used if your primary method of birth control did not work (for example, you missed birth control pills, a condom broke or fell off, or you forgot to use any birth control). It is available over-the-counter without prescription.

Plan B is used to help prevent pregnancy after sex and must be taken within 72‑hours after unprotected sex or if your primary birth control failed. The sooner you take it, the better it will work. It is not meant to be used as a regular form of birth control.

Plan-B One Step is often referred to as the "morning-after pill", but it works best the sooner you take it. Plan B One-Step is one single tablet that contains a higher dose of levonorgestrel (1.5 mg) than birth control pills, but it works in a similar way to prevent pregnancy.

Plan B One Step and other forms of emergency contraception won’t work if you’re already pregnant, and it won’t harm an existing pregnancy. It is not an abortion pill. However, emergency contraception does not prevent HIV or other sexually transmitted infections (like gonorrhea or chlamydia). Use a condom to prevent sexually transmitted diseases.

Where can I get Plan B One-Step right now?

• In the U.S. Plan B One Step (levonorgestrel 1.5 mg) and its equivalents are available without a prescription or an identification card at pharmacies or other retail shops (for example: CVS, Rite Aid, Walmart, Target, Walgreens).
• You or someone else can go to the store and buy it, order online from many pharmacies or stores, and even have same day delivery or pick up from a store.
• Emergency contraceptives like Plan B One Step are legal in all 50 states.
• If you do not see it on the shelf, ask the pharmacist in case it is kept behind the counter. Some pharmacies may be open 24 hours, 7-days a week in your neighborhood, but call to be sure.

Other names for the single dose levonorgestrel emergency contraceptive pill include:

• Athentia Next
• Fallback Solo
• Her Style
• Next Choice One Dose
• Opcicon One Step
• levonorgestrel 1.5 mg (generic)

Generics and store brands will be less expensive, so ask your pharmacist about cost-savings. Some emergency contraceptive pills cost as low as $10 using an online discount coupon.

Plan B One Step and its equivalents are meant as a backup method to help prevent pregnancy and should not be used as a regular form of birth control. Talk with your doctor or healthcare professional about the many forms of reliable birth control available.

Plan B (not Plan B One Step) was the original brand of emergency contraceptive which contained two levonorgestrel 0.75 mg tablets, but it is now discontinued from the U.S. market.

You must do the following to use hormonal emergency contraceptives (like Plan B One Step) properly:

• Use hormonal emergency contraception exactly as directed. Read and follow the instructions on the package you receive.
• Use condoms for the rest of your cycle. You can still get pregnant if you ovulate later than you usually do.
• Follow up with your healthcare provider to talk about the best long-term birth control method for you.

How well does Plan B One Step work?

Plan B One Step and other levonorgestrel 1.5 mg EC pills have a pregnancy rate of about 1% to 7% percent (1 to 7 out of 100 people will get pregnant, even if they use Plan B One Step correctly).

How well Plan B One Step works depends on a few things, including how quickly you take the pill after having intercourse, your weight, and where you are in your cycle. You may still get pregnant after using emergency contraception, but your chances are greatly reduced.

In general, the sooner you take emergency contraceptive pills (EC) after sex, the better they work. Because of this, it’s usually better to have purchased the EC beforehand in case you need it.

The best emergency contraceptive is the copper intrauterine device (IUD) that must be inserted by a healthcare provider. The copper IUD (Paragard) can be expensive if you don't have insurance, but it can last for up to 10 years. It should be inserted within 5 days of unprotected sex.

If you find that your normal method of birth control fails frequently (for example: the condom breaks, you forget to take your birth control pill or use other form of birth control), it may be better to use birth control you don't have to remember (such as an IUD, implant, or shot). Speak to your healthcare provider about other reliable birth control options that do not require a daily schedule.

Learn more: Missed your birth control pill? Here's what to do

What are the side effects of Plan B One Step?

Emergency contraceptive pills are normally well-tolerated by most people and side effects tend to be mild. The most common side effects of hormonal contraception include:

• Nausea
• Vomiting
• Spotting, irregular or heavy bleeding, delayed or early period
• Breast tenderness
• Dizziness
• Fatigue, feeling tired
• Headache
• Stomach cramps or pain

If you feel sick to your stomach or vomit, ask your doctor for medication to help with nausea. If you vomit within 2 hours of taking a levonorgestrel-containing emergency contraceptive pill or within 3 hours of ulipristal (Ella), contact your doctor as a repeat dose may be needed.

What types of emergency contraception are available?

Intrauterine Device (IUD)

The copper IUD (Paragard) is the best form of emergency contraception to help prevent a pregnancy. It should be inserted within 5 days of unprotected sex and requires a doctor visit for insertion.

The copper in the IUD helps to slow down sperm motility, therefore the sperm have a more difficult time getting to the egg to fertilize it. IUDs for emergency contraception are effective in women of any weight.

The copper IUD (Paragard) can be expensive if you don't have insurance, but it can be left in for long-term birth control as it can last for up to 10 years. It should be inserted within 5 days of unprotected sex.

Ella (ulipristal)

Ella (ulipristal) is an emergency contraceptive pill that may be used for up to 5 days after unprotected sex or a contraceptive failure, but it requires a prescription from a doctor.

In some U.S. states, Ella is available directly from the pharmacist (Alaska, California, Hawaii, Maine, Massachusetts, New Hampshire, New Mexico, Vermont, Washington.) Ella is not intended for routine use as a contraceptive.

After use of Ella, a reliable barrier method of contraception (such as a condom) should be used with sexual intercourse that occurs in that same menstrual cycle.

Ella should not be used more than once in the same menstrual cycle. Do not take Ella with levonorgestrel-containing emergency contraceptive pills (like Plan B One Step) because it may lower the effectiveness. Other hormonal contraception (such as the pill which is taken daily) should not be taken for at least five days after taking Ella (ulipristal). Instead, a barrier contraception (such as condoms) should be used until menstruation occurs.

Plan B One Step (and generic equivalents)

You can use a levonorgestrel emergency contraceptive (EC) pill such as Plan B One Step, Next Choice One Dose, EContra One Step, or similar products for up to 72 hours (3 days) after unprotected sex, but it works better the sooner you take it, so do not delay in getting it.

These products are available over-the-counter (OTC) without a prescription in the U.S., but speak to your pharmacist if you cannot find it on the shelves. In the U.S., these are available without age restrictions to women and men and no ID is required. You can get EC pills ahead of time so that you always have them if needed.

Being overweight or obese may lower how well emergency contraceptive pills work to prevent pregnancy. If you are overweight or obese, you may want to consider having an intrauterine device (IUD) inserted. IUDs for emergency contraception are very effective in women of any weight.

Birth Control Pills (higher doses)

Higher doses of hormonal birth control pills containing both estrogen and progestin can be used as an emergency contraceptive, taken as two doses 12 hours apart. However, the number of pills you would take will depend upon the brand you are taking.

A doctor, clinic nurse, or pharmacist can tell you how many pills you should take based on the type and brand of oral birth control that you use. Call your healthcare provider as soon as possible.

Related: Emergency Contraception: What You Need to Know

This is not all the information you need to know about Plan B One Step (levonorgestrel 1.5 mg) for safe and effective use and does not take the place of your doctor’s directions. Review the full product information and discuss this information and any questions you have with your doctor or other health care provider.