The emergency drug is used to prevent pregnancy after an un-protected sex, it is usually taken within 72-120 hours after sex activities, and it can be taken for no more than 3 times a year, otherwise will lead to habitual abortion.
While there are some side effects may appear after taking morning after pill, such as nausea, vomiting, irregular uterine bleeding, the change of menstruation and ovulatory period. The spotting after taking the emergency pill is also clinically called withdrawal bleeding. While, if the pill is taken in the former part of your menstruation cycle, which will make a greater interference like vaginal bleeding. If in the later period, which cause a less influence for women, even you could treat it as the menstruation bleeding if the amount of bleeding is equal to your normal flow, you could, and don't need to worry too much, that will restore automatically. However, if you take too many times in a short time, that will cause disorder menstruation and a lower success rate of contraception.
What's more, some people are forbidden to take morning after pill, especially the women with the gynecological tumor or breast diseases, which may aggravate their symptoms. And don't take it for a long time.