Birth Control Pills

Levonorgestrel is used by women to prevent pregnancy after birth control failure (such as a broken condom) or unprotected sex. This medication is an emergency contraceptive and should not be used as a regular form of birth control. ... This effect can result in pregnancy.

Yaz is a combination birth control pill containing female hormones that prevent ovulation (the release of an egg from an ovary). Yaz also causes changes in your cervical mucus and uterine lining, making it harder for sperm to reach the uterus and harder for a fertilized egg to attach to the uterus