Misuse of emergency contraceptive pills may result in nausea, vomiting, irregular vaginal bleeding and menstrual disorders, induced miscarriage and abnormal embryo development. 1. Non-pregnant adult females: Some females may have no obvious abnormality after taking the pill. Some of them may experience nausea, vomiting, irregular vaginal bleeding and menstrual disorders after taking the drug, which generally do not require treatment. 2. Pregnant women: taking emergency contraceptive pills after pregnancy may induce miscarriage and abnormal embryonic development, resulting in fetal malformation. If pregnant women mistakenly take emergency contraceptive pills, it is best to go to the hospital under the guidance of a doctor to determine the size of the chances of adverse effects on the fetus according to the gestational week, and take appropriate measures. 3. Underage female children: If the dose is very small, there may be no obvious symptoms. If the dose is large, it may cause symptoms such as pseudo-development of breasts and vaginal bleeding in female children. If you take emergency contraceptive pills by mistake, it is recommended that you seek medical advice and treatment under the guidance of a doctor.