Plan B One-Step is an emergency contraception pill that people can take in some instances to prevent pregnancy. This pill is effective if people forget to take their birth control pill and have unprotected sex or if another birth control method fails.

It is essential that people who decide to use the Plan B pill continue to take their birth control pills as usual unless a doctor advises otherwise. Taking both types of pill can provide a more lasting form of contraception.

The Plan B pill usually contains higher doses of hormones than birth control pills so taking both pills can cause some side effects.

According to the manufacturers of Plan B One-Step, people should resume taking birth control pills immediately after taking the Plan B pill.

Taking birth control pills after taking the Plan B pill can help to prevent unwanted pregnancy going forward.

Does it affect the next period?

Plan B Levonorgestrel morning after pill.Share on Pinterest
A person should continue to use birth control while taking the Plan B pill.

Taking the Plan B pill in addition to continuing to take birth control pills may result in the next period being slightly different than usual.

For example, periods may:

  • be earlier or later than expected
  • be heavier or lighter than usual
  • cause more symptoms, such as nausea or cramping

If a person’s period is more than a week later than expected after taking Plan B, they should take a pregnancy test to rule out pregnancy. Anyone who has concerns about taking birth control pills or the Plan B pill should talk to a doctor.

It is possible to take the Plan B pill up to 3 days after unprotected sex, even though many people call it the “morning-after” pill. However, the sooner a person takes Plan B following unprotected intercourse, the more effective it is in preventing pregnancy.

The Plan B pill contains 1.5 milligrams (mg) of the hormone levonorgestrel. Levonorgestrel is a synthetic chemical that mimics the natural hormone progesterone. It triggers several responses in the body that prevent pregnancy.

Levonorgestrel ensures that the body is:

  • Preventing ovulation, the process by which the ovary releases an egg. If there is no egg to fertilize, pregnancy is not possible.
  • Thickening the mucus in the cervix, which helps prevent sperm from reaching the uterus and combining with an egg.
  • Thinning the uterine lining, which reduces the likelihood of a fertilized egg attaching to the uterus.

There are many misconceptions regarding how the Plan B pill works. The pill is not an abortion pill as it does not destroy or damage a fetus. Instead, it prevents a pregnancy from occurring in the first place. Once an embryo has implanted in the uterus, Plan B will not disrupt it or cause an abortion.

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A person who is already pregnant should not take Plan B.

Anyone who has had unprotected sex or failure of their birth control method can take the Plan B pill. This pill is available without a prescription and has no age restrictions.

Some people should avoid taking Plan B, including those who are:

  • already pregnant
  • allergic to levonorgestrel or any other ingredients present in the Plan B pill
  • trying to use it as an alternative to regular birth control (Plan B is effective in one-time doses, but is not suitable for routine pregnancy prevention)
  • male, as the hormone is not effective in preventing a male from getting females pregnant

There are some potential side effects of taking the Plan B pill. Side effects are usually most significant in the 1–2 days after taking the pill and should subside after that.

A primary consequence of taking the pill is that the next period may be different regarding timing, flow, and side effects.

If a person’s period is more than a week late, they should take a pregnancy test to ensure that they are not pregnant.

It is essential to understand that taking the Plan B pill does not protect people from sexually transmitted infections (STIs).

Taking Plan B can cause side effects in some people due to the elevated hormone levels in the body.

Typical side effects may include:

  • breast tenderness
  • dizziness
  • a headache
  • irregular bleeding
  • nausea
  • vomiting

Some people may find that taking anti-nausea medications, such as Dramamine, or taking Plan B on a full stomach makes them less likely to experience stomach-related side effects.

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Some medications can make Plan B less effective.

The Plan B pill contains larger amounts of the hormones that are present in birth control pills.

Taking this emergency contraceptive causes a boost in the body’s hormone levels, which increases the likelihood of preventing pregnancy.

However, there are medications and herbal supplements that could affect the way the Plan B pill works.

Medications that may make Plan B less effective include:

  • barbiturates
  • carbamazepine
  • felbamate
  • griseofulvin
  • oxcarbazepine
  • phenytoin
  • rifampin
  • St. John’s wort
  • topiramate

People should always ask a doctor or pharmacist about any medications they may be taking and how they could impact the effectiveness of Plan B medication.

People should continue taking birth control pills as usual even after taking the Plan B pill.

The Plan B pill is only intended to be an emergency medication, not a regular method of contraception.

If someone has difficulty maintaining a regular birth control pill schedule, they should talk to their doctor about other birth control methods, such as intrauterine devices (IUDs).