The main function of the emergency contraceptive pill is to prevent pregnancy. If you do not take proper contraceptive measures after having intercourse during ovulation, the possibility of pregnancy is very high. The main effects of taking emergency contraceptive pills during ovulation include: 1. delaying or inhibiting the ovulation function of the ovaries, so that the eggs can not be discharged normally and play a contraceptive role; 2. although the eggs have been discharged, emergency contraceptive pills can change the nature of the mucus in the cervix, so that sperm can not pass through the cervix into the uterine cavity, and naturally can not fertilize the eggs; 3. if a fertilized egg has been formed, emergency contraceptive pills 3. If a fertilized egg has been formed, the emergency contraceptive pill can change the nature of the endometrium, so that the fertilized egg cannot be laid normally and play a contraceptive role.