How does emergency contraception reduce the risk of pregnancy?

Emergency contraception reduces the risk of pregnancy because it delays the movement of the tubes, which is where the egg goes from the ovary to the uterus against the sperm.

Explanation:

Emergency contraception may inhibit or only delay ovulation. This is because this type of contraceptive contains a high concentration of progesterone. This hormone delays the movement of the tubes, which is where the egg goes from the ovary to the uterus against the sperm - and the sperm comes from the uterus through the tube to meet the egg. This also makes it difficult for sperm to penetrate the cervical mucus, as progesterone alters the consistency of the mucus, making the environment hostile to sperm.