The first time you take yutin, the damage is not very big. Yutin belongs to levonorgestrel, a fully synthetic potent progestin that acts on the hypothalamus and pituitary gland to inhibit ovulation, make the endometrium thinner, prevent fertilized eggs from coming to bed, while making the cervical mucus sticky and preventing sperm from penetrating and playing a remedial role. The most common adverse effects of the emergency contraceptive pill are nausea, vomiting, and irregular vaginal bleeding, which can affect normal endocrine hormone levels and lead to late menstrual irregularities. Generally, it should not be used more than three times a year, and at most once a month. Occasionally, the effect of taking Yutin is not great, but it should never be used more than once. The emergency contraceptive pill can only be used as a remedial measure, not as a common method of contraception. If used repeatedly, it may lead to an increase in the probability of infertility later in life.