If you use an emergency tablet, you can still get pregnant. There are no data that could confirm the effectiveness of this form of contraception. However, specialists agree that the sooner a tablet is taken, the greater its effectiveness in preventing pregnancy . Both types of tablets – used for 72 or 120 hours, can cause nausea, dizziness and headache, fatigue. Pain may occur – breast pain and stomach ache. Using this form of contraception may alter your menstrual cycle. If you vomit within two hours of taking a ’72 hour’ tablet, or three hours of taking a pill that can be taken up to 120 hours after intercourse, seek medical advice. As a result of vomiting and the likelihood that the agent has not absorbed into the blood, you may need to take an extra dose. Less than 1% of women using an IUD as a method of emergency contraception become pregnant, while pregnancy is not uncommon after using a contraceptive pill. Emergency contraception is not associated with serious side effects. Emergency contraception does not cause abortion. Emergency tablet and pregnancy prevention The emergency tablet is not taken preventively. The tablet that should be taken up to 72 hours after intercourse contains a synthetic equivalent of progesterone (a naturally occurring hormone). Progesterone plays a role in ovulation and preparing the uterus to accept a fertilized egg. The tablet prevents or delays ovulation.