What are the side effects of emergency contraceptive pills?
Sep 16, 2025
Source: Cainiu Health
Dr. Zhang Lu
Introduction
In general, emergency contraceptive pills are used as a post-coital contraceptive measure. Possible side effects after taking them include menstrual disorders, gastrointestinal discomfort, breast tenderness, dizziness, headaches, and irregular vaginal bleeding. Emergency contraceptive pills should not be used frequently. It is recommended to use them no more than three times a year and no more than once per month. Regular contraceptive methods should be prioritized for daily use.
Generally, emergency contraceptive pills are used as a post-coital measure to prevent pregnancy. After taking the pill, possible side effects may include menstrual irregularities, gastrointestinal discomfort, breast tenderness, dizziness or headaches, and irregular vaginal bleeding. The details are as follows:
1. Menstrual irregularities: Emergency contraceptive pills contain high doses of hormones, which can disrupt the normal endocrine cycle, potentially causing menstruation to occur earlier or later than expected. When periods come early, the flow may be slightly lighter than usual; delays typically do not exceed one week.
2. Gastrointestinal discomfort: Some individuals may experience nausea, vomiting, or loss of appetite after taking the pill. These symptoms usually appear within 24 hours of ingestion, are generally mild, and resolve on their own within 1–2 days.
3. Breast tenderness: Hormonal fluctuations can stimulate breast tissue, leading to mild soreness or tenderness, similar to sensations experienced before a regular menstrual period. This usually requires no special treatment and gradually subsides as hormone levels return to normal.
4. Dizziness or headache: A small number of people may develop mild dizziness or headaches after taking the pill, likely due to temporary effects of the drug on the nervous system. These symptoms typically do not interfere with daily activities and resolve spontaneously within 1–2 days with rest. Avoiding strenuous activity may help reduce discomfort.
5. Irregular vaginal bleeding: About one week after taking the pill, some individuals may notice light spotting or breakthrough bleeding, significantly lighter than a normal menstrual flow. This usually lasts for 2–3 days and stops on its own. It results from hormonal changes causing slight shedding of the uterine lining and is considered a common reaction.
Emergency contraceptive pills should not be used frequently. It is recommended to use them no more than three times per year and no more than once per month. Regular contraceptive methods should be prioritized for daily use. After taking the pill, it's important to get adequate rest, avoid excessive fatigue, and maintain a light diet, which can help alleviate potential side effects.
