Plan B Explained

What is Plan B?

What is Plan B?

Plan B, also known as the morning-after pill, is an emergency contraceptive that women can take when they’ve had unprotected sex or the form of birth control used during sex has failed[1][2]. 

Plan B contains either levonorgestrel (Plan B One-Step) or ulipristal acetate (ella)[1][2]. 

How does it work?

The purpose of Plan B is to prevent or delay ovulation. Ovulation is a regular part of a woman’s menstrual cycle where the ovaries release an egg which can then be fertilized by sperm, leading to the fetal development process. It’s not possible to become pregnant without ovulation. Plan B will not prevent pregnancy if you have already ovulated[2].

The morning-after pill is taken as soon as possible after unprotected sex. Plan B One-Step may be taken up to 72 hours after sex, and ella may be taken up to 120 hours after sex.

Plan B is not the abortion pill. The abortion pill terminates an already existing pregnancy where the fertilized egg has implanted in the uterus and has begun to develop[1]. The morning-after pill does not prevent a pregnancy once the embryo has already implanted in the uterus[1][2]. 

The morning-after pill is not to be used as a regular form of birth control. It has the potential to fail and does not protect against sexually transmitted infections (STIs). It may be less effective if you are overweight with a high BMI[1][2]. 

Common side-effects of Plan B

All medication can come with some side effects. For Plan B, these can include:

  • Changes to your normal period (could be later or earlier than usual)
  • Spotting
  • Nausea and vomiting
  • Fatigue
  • Headaches
  • Dizziness
  • Breast tenderness
  • Lower abdominal pain[1][2]
    • If you have severe abdominal pain 3-5 weeks after using Plan B, see a doctor immediately. This could be a sign of ectopic pregnancy

What if I still haven’t gotten my period after taking Plan B?

The morning-after pill is most effective if taken as soon as possible, but it still doesn’t always work. If you’ve taken Plan B and your period is more than one week late, take a pregnancy test[2]. 

If you think you could be pregnant, we offer free and confidential medical grade pregnancy test verifications and limited obstetric ultrasounds to confirm pregnancy. 

During these appointments, you’ll have the opportunity to speak one-on-one with Care Clinic’s registered nurse, ask her all the questions you might have, and talk with someone through all your options.

*Care Pregnancy Resource Center and Care Clinic do not perform or refer out for abortions. We also do not provide the morning-after pill. All medical services are provided through referral relationship with onsite Care Clinic. Care Clinic is staffed by licensed medical professionals.


  1. Mayo Clinic. (2022, June 3). Morning-after pill. Retrieved from
  2. Cleveland Clinic. (2022. July 1). Morning-After Pill. Retrieved from