If you’re sexually active, there’s always a chance that you could get pregnant, even if you’re using protection. Perhaps you’re thinking about taking Plan B to avoid an unexpected pregnancy. However, Plan B isn’t a simple fix and it’s not without risk. It’s important to be aware of how Plan B could affect your body and know what to do if it fails.


Today, we’re discussing Plan B—including how it works, the potential risks and side effects, and what to do if you still get pregnant after taking it. Keep reading to learn more!

How Does Plan B Work?

Plan B is a form of emergency contraception (also known as emergency birth control) that aims to lower the risk of pregnancy by delaying or preventing ovulation[1]. It’s important to know that Plan B (and all other forms of emergency contraception) should not be used in place of regular birth control[1]. It should also be noted that Plan B tends to be less effective for women who weigh 165 pounds or more[2]

Is Plan B the Same as the Abortion Pill? Can Plan B Cause Miscarriage?

They may seem similar, but Plan B and the abortion pill aren’t considered the same things. The difference is that the goal of Plan B is to delay or prevent ovulation, while the abortion pill ends a pregnancy that has already begun[1]


That being said, in rare cases, Plan B can prevent a fertilized egg from implanting into the uterus[3]. The embryo is never able to develop into a viable pregnancy and is eventually miscarried.  

What are the Side Effects of Plan B?

It’s important to be aware of the potential side effects of Plan B so you can protect your health and make a fully informed decision! Common side effects of Plan B include[1]:


  • Irregular periods
  • Dizziness
  • Headaches
  • Fatigue
  • Cramps or abdominal pain 
  • Nausea or vomiting
  • Breast tenderness
  • Allergic reaction to levonorgestrel (a hormone found in Plan B)

Can Plan B Cause Irregular Periods?

As mentioned above, Plan B can cause irregular periods, which can be alarming if you’re concerned that you might be pregnant. After taking Plan B, your period could be delayed for up to a week[1]. You may experience bleeding between periods and a heavier flow during your next period[1].


Contact your doctor immediately if you experience bleeding or spotting for longer than a week or severe abdominal pain three to five weeks after taking Plan B. These symptoms can indicate that you became pregnant, but a miscarriage or ectopic pregnancy occurred[1].

What to Do if Plan B Fails

If period is delayed for more than three to four weeks after taking Plan B, it may be a sign that it failed[1]. The next step is to determine whether or not you’re pregnant. We understand how scary this next step can be, but you don’t have to take it alone! Consider scheduling a free pregnancy test and free ultrasound at Richland Pregnancy Center! 


If your results come back positive, don’t panic. Our compassionate client advocates and mentors are here to help you explore all of your pregnancy options so that you can make an informed and empowered decision! We will do everything we can to equip you to make your next move with confidence!


Don’t wait to get the care you deserve! Give us a call at (419) 522-8862 or schedule your appointment online today!



  1. Mayo Foundation for Medical Education and Research. (2022, June 3). Morning-after pill. Mayo Clinic. Retrieved from https://www.mayoclinic.org/tests-procedures/morning-after-pill/about/pac-20394730#  
  2. Cleland, K., Raymond, E. G., Westley, E., & Trussell, J. (2014, December). Emergency contraception review: Evidence-based recommendations for clinicians. Clinical Obstetrics and Gynecology. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4216625/  
  3. Embryocidal Potential of Modern Contraceptives. AAPLOG. (2020, January 15). Retrieved from https://aaplog.org/wp-content/uploads/2020/01/FINAL-CO-7-Embryocidal-Potential-of-Modern-Contraception-1.20.20.pdf

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