What symptoms could be felt after taking a levonorgestrel (Plan B) tablet?

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Last updated: April 10, 2025View editorial policy

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From the Guidelines

Levonorgestrel tablets can cause side effects such as nausea, abdominal pain, fatigue, headache, dizziness, breast tenderness, and changes in menstrual bleeding patterns after taking them. These side effects are generally mild and temporary, resolving on their own within a day or two 1. Some women may experience irregular spotting or bleeding before their next period, or their next period might come earlier or later than expected. Less common side effects include vomiting, diarrhea, and back pain. It's worth noting that the levonorgestrel regimen is associated with significantly less nausea than combined estrogen and progestin ECPs, according to a systematic review 1. If you experience severe abdominal pain, extremely heavy bleeding, or if side effects persist beyond a few days, you should contact a healthcare provider. These side effects occur because levonorgestrel is a synthetic hormone that temporarily alters your body's natural hormone levels to prevent pregnancy. Drinking plenty of fluids and taking over-the-counter pain relievers like ibuprofen may help manage some of these symptoms. Key points to consider include:

  • Nausea and vomiting are less common with levonorgestrel compared to combined estrogen and progestin ECPs 1
  • Antiemetics can be effective in reducing nausea and vomiting, but their use should be considered on a case-by-case basis 1
  • Most side effects are temporary and resolve within a day or two 1

From the FDA Drug Label

some women may have changes in their period, such as a period that is heavier or lighter or a period that is early or late. Side effects may include changes in your period, nausea, lower stomach (abdominal) pain, tiredness, headache, dizziness, and breast tenderness When using this product you may have menstrual changes tiredness dizziness nausea headache breast pain lower stomach (abdominal) pain vomiting

The possible side effects that could be felt after taking levonorgestrel tablet include:

  • Menstrual changes: heavier or lighter period, early or late period
  • Nausea
  • Lower stomach (abdominal) pain
  • Tiredness
  • Headache
  • Dizziness
  • Breast tenderness
  • Vomiting 2 2

From the Research

Side Effects of Levonorgestrel

The provided studies do not directly address the side effects of levonorgestrel tablets. However, they discuss the efficacy and usage of levonorgestrel for emergency contraception.

Efficacy of Levonorgestrel

  • The studies suggest that levonorgestrel is an effective form of emergency contraception when taken before ovulation 3.
  • The efficacy of levonorgestrel may be affected by body weight, with some studies suggesting that it may be less effective in women with a higher body mass index (BMI) 4, 5.
  • However, other studies have found that the overall pregnancy rate is low (1-2%) and that there is no direct evidence that lower levonorgestrel plasma levels contribute to an increased pregnancy rate in obese women 5.

Usage of Levonorgestrel

  • Levonorgestrel can be taken orally, and it is available over the counter for women of all ages 4.
  • It can also be administered vaginally, but this method may not cause significant changes in endometrial receptivity 6.
  • Some studies have explored the use of levonorgestrel in combination with other forms of contraception, such as the copper intrauterine device (IUD) 7.

Potential Symptoms

Although the studies do not directly address the side effects of levonorgestrel, other sources may indicate that common side effects include:

  • Nausea and vomiting
  • Abdominal pain
  • Fatigue
  • Headache
  • Dizziness
  • Breast tenderness

It is essential to consult the packaging or a healthcare professional for more information on potential side effects.

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Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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