What are the side effects of emergency contraceptive pills?

Generally, common emergency contraceptive pills include levonorgestrel tablets, enteric-coated levonorgestrel tablets, and mifepristone tablets. Side effects of emergency contraceptives may include menstrual disorders, nausea and vomiting, dizziness and fatigue, breast tenderness, and changes in mental status. It is recommended to use these medications as directed by a physician. Detailed explanations are as follows:

1. Menstrual Disorders

Emergency contraceptive pills usually contain high doses of progestin, which can affect the hypothalamic-pituitary-ovarian axis after intake, disrupting normal hormone secretion and feedback mechanisms. This may lead to early or delayed menstruation, and menstrual flow may increase or decrease.

2. Nausea and Vomiting

Due to the high levels of hormones in emergency contraceptives, these hormones may irritate the gastrointestinal tract, causing symptoms such as nausea, vomiting, diarrhea, or abdominal pain. These symptoms typically resolve naturally within a day after taking the medication.

3. Dizziness and Fatigue

The hormones in emergency contraceptives may affect nervous system function and energy metabolism. Hormonal interference with neurotransmitter balance can disrupt nerve conduction, leading to dizziness. The drug's impact on metabolism may result in relatively insufficient energy supply to the body, causing a feeling of fatigue that can affect daily activities and work efficiency.

4. Breast Tenderness

The progestin in emergency contraceptives can promote the proliferation of mammary ducts and alveoli, altering the physiological state within the breasts and causing breast tenderness or pain upon touch. These symptoms typically appear within a few days after taking the medication. As the body adapts to the hormonal changes, symptoms gradually subside.

5. Changes in Mental Status

Emergency contraceptives affect hormone levels in the body, which are closely related to the nervous system. The medication may interfere with the normal secretion and metabolism of neurotransmitters such as serotonin and dopamine. Serotonin plays a crucial role in regulating mood and sleep; its imbalance can lead to mood swings, anxiety, depression, and other changes in mental status.

Emergency contraceptives have numerous side effects and a certain failure rate, so frequent use should be avoided as much as possible. If pregnancy is not desired, other more reliable contraceptive methods should be adopted, such as intrauterine device placement or condom use.