What is the harm of taking contraceptives twice a year?

Contraceptives include long-acting contraceptives, short-acting contraceptives, and emergency contraceptives. Contraceptives are mostly made up of estrogen and progesterone, mainly through different links that affect the reproductive process, so as to achieve the purpose of anti-fertility. Although contraceptives are used for contraception, but also can not be taken frequently, for emergency contraceptives, do not take more than 3 times a year, take emergency contraceptives twice a year harm is not particularly large, some women taking emergency contraceptives may show lack of appetite, nausea, vomiting, fatigue, dizziness, menstrual changes and other performance, some women may also show secondary infertility. Suggest female friends after taking contraceptives, show any discomfort, must go to the regular hospital in time for examination.