Are there any side effects after taking emergency contraceptive pills?
Jun 23, 2025
Source: Cainiu Health
Dr. Zhang Lu
Introduction
In general, taking emergency contraceptive pills after intercourse may be accompanied by side effects such as nausea, vomiting, breast tenderness, headache, and fatigue. After taking emergency contraceptive pills, one should closely monitor any physical reactions and seek medical attention promptly if any discomfort occurs. Meanwhile, it is recommended that women adopt safer and more effective contraceptive methods in daily life, such as using condoms or taking short-term oral contraceptives.
Generally, taking emergency contraceptive pills after intercourse may be accompanied by side effects such as nausea, vomiting, breast tenderness, headache, and fatigue. Detailed explanations are as follows:
1. Nausea
Emergency contraceptive pills contain high-dose hormones, such as levonorgestrel. These hormones interfere with the normal physiological environment and hormonal regulation mechanisms of the gastrointestinal tract after entering the body. The gastrointestinal mucosa is sensitive to hormonal changes, and the sudden increase in hormone levels may stimulate gastrointestinal nerves, causing nausea. Moreover, hormones may also affect the rhythmic peristalsis of the gastrointestinal tract, leading to gastrointestinal dysfunction and further exacerbating nausea.
2. Vomiting
Vomiting is a further progression of nausea. When nausea is severe, the stomach muscles are stimulated and contract strongly, expelling stomach contents through the esophagus and out of the mouth. The strong stimulation of the gastrointestinal tract by the hormonal components in emergency contraceptive pills, along with possible gastrointestinal spasms, can trigger vomiting. Additionally, individual differences in drug tolerance mean that people sensitive to hormones are more likely to experience vomiting.
3. Breast Tenderness
The hormones in emergency contraceptive pills interfere with a woman's natural estrogen and progesterone levels. Breast tissue is highly sensitive to hormonal changes, and fluctuations in hormone levels can cause breast tissue congestion, edema, and ductal dilation, resulting in breast tenderness. This sensation may resemble premenstrual breast tenderness but may be more pronounced. It typically occurs within a few days after taking the pill and gradually subsides as the body adapts to the hormonal changes.
4. Headache
Rapid changes in hormone levels can affect the vasomotor function of cerebral blood vessels. Hormones in emergency contraceptive pills may cause vasodilation or vasoconstriction of cerebral vessels, altering intracranial pressure and triggering headaches. Furthermore, hormones may affect the balance of neurotransmitters, leading to nervous system dysregulation and worsening headache symptoms. Headache severity and characteristics vary among individuals, ranging from mild dull pain to severe throbbing or pulsating pain.
5. Fatigue
The hormones in emergency contraceptive pills significantly affect the body's endocrine system, disrupting normal physiological metabolic processes. The body must expend additional energy to adapt to these hormonal changes, resulting in feelings of fatigue. Hormonal fluctuations may also affect sleep quality, making it difficult to achieve deep sleep at night, which can lead to daytime drowsiness and fatigue.
Therefore, after taking emergency contraceptive pills, it is important to closely monitor physical reactions, and seek medical attention promptly if any discomfort occurs. It is also recommended that women adopt safer and more effective contraceptive methods in daily life, such as using condoms or taking short-acting oral contraceptives.
