Plan B

Primary Indications

Plan B is used as emergency contraception to reduce the risk of pregnancy after a single episode of unprotected sex. It is intended for backup use and is most effective when taken as soon as possible.

Common Situations for Use

This medication is typically used in the following circumstances:

• Unprotected sexual intercourse.
• Failure of a primary birth control method, such as a condom breaking or slipping.
• Missing one or more doses of regular birth control pills.
• Being late for a scheduled contraceptive injection.
• Displacement of a diaphragm or cervical cap.
• Sexual assault.

Important Considerations

Plan B is not intended for routine use as a primary method of birth control. It does not provide long-term protection against pregnancy and does not protect against HIV infection or other sexually transmitted diseases. Additionally, this medication will not work if you are already pregnant and is not used to terminate an existing pregnancy.

How Plan B Prevents Pregnancy

Plan B contains levonorgestrel, a synthetic version of the hormone progesterone. It is designed to prevent pregnancy before it starts by interfering with the normal reproductive cycle. It works in the following ways:

• Delaying Ovulation: The primary way this medication works is by stopping or delaying the release of an egg from the ovary. If there is no egg available for sperm to fertilize, pregnancy cannot occur.
• Preventing Fertilization: It may also work by preventing sperm from reaching and fertilizing an egg that has already been released.
• Altering the Uterine Lining: It may change the lining of the uterus to prevent a fertilized egg from attaching (implanting), although its main effect is believed to occur before fertilization.

Plan B is an emergency contraceptive and is not the same as an abortion pill. It will not work if a person is already pregnant, and it cannot end or disrupt an established pregnancy. Because it works by preventing the start of a pregnancy, it is most effective when taken as soon as possible after unprotected intercourse.

Common Side Effects

Most side effects from Plan B are mild and usually resolve within a few days. Common symptoms include:

• Nausea and vomiting
• Stomach pain or cramping
• Fatigue
• Dizziness
• Headache
• Breast tenderness

Menstrual Changes

Plan B can affect your next menstrual cycle. You may notice:

• Your period starting earlier or later than expected
• Heavier or lighter bleeding than usual
• Spotting before your next period

If your period is delayed by more than one week, it is recommended to take a pregnancy test.

Serious Side Effects

Seek medical help immediately if you experience severe pain in the lower abdomen or side. This could indicate an ectopic pregnancy, which is a medical emergency that occurs when a fertilized egg implants outside the uterus.

General Precautions

Plan B is intended for emergency use only and is not a substitute for regular methods of birth control. It does not provide protection against HIV infection (AIDS) or other sexually transmitted diseases (STDs).

Existing Pregnancy

This medication is not effective if a pregnancy has already occurred. It is not an abortifacient and will not terminate an existing pregnancy. If the next menstrual period is more than one week late, a pregnancy test should be performed to rule out pregnancy.

Ectopic Pregnancy

Severe abdominal pain may indicate an ectopic pregnancy, which is a pregnancy that develops outside the uterus. This is a serious medical condition that requires immediate evaluation by a healthcare professional, regardless of emergency contraceptive use.

Menstrual Changes

The timing and flow of the next menstrual period may be affected. The period may occur earlier or later than expected, and bleeding may be heavier or lighter than usual. Spotting between periods may also occur.

Vomiting

If vomiting occurs within two hours of taking the medication, the dose may not have been fully absorbed. In such cases, a healthcare provider should be consulted to determine if a repeat dose is necessary.

Allergies

Plan B should not be used by individuals with a known hypersensitivity or allergy to levonorgestrel or any of the inactive ingredients in the tablet.

Pregnancy

Plan B is intended for emergency contraception and should not be taken if you are already pregnant. It is not an abortion pill and will not end a pregnancy that has already begun. If you accidentally take this medication while pregnant, evidence suggests it will not harm the developing fetus or affect the pregnancy.

Breastfeeding

Levonorgestrel, the active ingredient in Plan B, can pass into breast milk. Most healthcare experts consider it safe to use while breastfeeding. To minimize the amount of medication the baby receives, you may choose to take the pill immediately after a nursing session.

If you have questions about the timing or safety of emergency contraception, speak with a healthcare provider.

Available Forms

Plan B is provided in the following form:

• Oral Tablet: This medication is a tablet designed to be taken by mouth.

The medication is intended for use as soon as possible after unprotected intercourse or a known contraceptive failure.

FDA Approval and Availability

The U.S. Food and Drug Administration (FDA) approved Plan B One-Step (1.5 mg levonorgestrel) as an emergency contraceptive. It is available over-the-counter (OTC) without a prescription, and there are no age requirements or identification needed for its purchase.

Approved Indications

The medication is indicated for the prevention of pregnancy following unprotected sexual intercourse or the known failure of a contraceptive method, such as a condom break or missed birth control pills. It is not intended for routine use as a primary form of birth control.

Regulatory Labeling Updates

The FDA has updated the labeling for levonorgestrel emergency contraceptives to clarify the medication's mechanism of action. The updated information specifies that the drug works by preventing or delaying the release of an egg from the ovary (ovulation). According to the FDA, current evidence indicates that the medication does not prevent a fertilized egg from implanting in the uterus and does not terminate an existing pregnancy.

Safety and Warnings

There are no Boxed Warnings or Risk Evaluation and Mitigation Strategies (REMS) associated with this medication. The FDA has determined that the medication is not an abortifacient because it works before pregnancy is established.

Timing and Success Rates

Plan B is intended for use as emergency contraception following unprotected intercourse or birth control failure. Its effectiveness is highly dependent on how quickly it is taken. While it is labeled for use up to 72 hours (3 days) after the event, it is most effective when taken within the first 24 hours. Research indicates that Plan B can reduce the risk of pregnancy by approximately 75% to 89% if taken within the 72-hour window.

Factors Influencing Effectiveness

• Time Elapsed: The probability of pregnancy increases the longer a person waits to take the medication.
• Ovulation: Plan B works primarily by delaying or preventing the release of an egg (ovulation). If ovulation has already occurred before the pill is taken, it may not be effective in preventing pregnancy.
• Existing Pregnancy: Plan B is not an abortion pill and will not end an established pregnancy. It is only effective if taken before a pregnancy has begun.
• Body Weight: Some studies suggest that emergency contraceptive pills containing levonorgestrel may be less effective in individuals with a higher body mass index (BMI).

Plan B is significantly less effective at preventing pregnancy than regular, long-term birth control methods such as daily oral contraceptives, intrauterine devices (IUDs), or implants. It is not intended for routine use as a primary form of contraception.