If you are taking the emergency contraceptive pill and have withdrawal bleeding for about a week, the probability of pregnancy is about 15%, which means that the success rate of remedy is about 85%. Retreat bleeding does not necessarily mean that the contraceptive is successful, it has nothing to do with the success of the contraceptive. It is generally recommended to come to the hospital for a blood draw or a pregnancy test more than 12 days after intercourse. The blood draw is the gold standard for ruling out pregnancy, and withdrawal bleeding is only a reaction to the stimulation of the local lining by progesterone, and has nothing to do with pregnancy, or with the success of contraception. Therefore, if you experience a delay in menstruation for more than a week or have early pregnancy reactions such as nausea, vomiting or dizziness, come to the hospital as soon as possible to confirm whether you are pregnant or not.