Upostelle is a form of emergency contraception, commonly referred to as the morning-after pill. It is designed to prevent pregnancy after unprotected sex or if a contraceptive method has failed. The active ingredient in Upostelle is levonorgestrel, a synthetic hormone that works primarily by stopping the release of an egg from the ovary (ovulation). It may also prevent fertilization of an egg (the uniting of sperm with the egg) or prevent a fertilized egg from attaching to the womb (implantation). Upostelle is most effective when taken as soon as possible after unprotected intercourse, ideally within 12 to 24 hours and no later than 72 hours (3 days). It is a single-dose tablet, which makes it convenient to use. However, it's important to note that Upostelle is not intended as a regular method of contraception and does not protect against sexually transmitted infections (STIs).