If you use a condom, the chances of pregnancy are greatly reduced, but there is no guarantee that you will not get pregnant 100% of the time. The main reason is that during intercourse, the condom may break or leak due to the quality of the condom or the roughness of the action. Once the condom is broken, a small amount of sperm may enter the vagina and an unwanted pregnancy may occur. To prevent this, you can check the condom before and after intercourse. Before intercourse, you can check the condom by blowing on it and after sex, you can check the condom by filling it with water. If no breakage is found in both checks, no unwanted pregnancy will occur. If the condom is found to be broken after intercourse, you can take the emergency contraceptive pill within 72 hours or place a copper-containing active birth control device within 72 hours, both of which are useful for emergency contraception.