Please provide examples of emergency contraceptives and their pharmacological effects.

1. Levonorgestrel (Plan B): Levonorgestrel is a progestin hormone that works by preventing ovulation and fertilization. It may also prevent implantation of a fertilized egg in the uterus.

2. Ulipristal acetate (ella): Ulipristal acetate is a selective progesterone receptor modulator that works by delaying or inhibiting ovulation. It may also prevent fertilization and implantation of a fertilized egg.

3. Copper Intrauterine Device (IUD): The copper IUD works by creating a hostile environment for sperm, preventing fertilization. It may also prevent implantation of a fertilized egg.

4. Combined oral contraceptives: Some combined oral contraceptives can be used as emergency contraceptives by taking a higher dose than usual. They work by preventing ovulation and thickening cervical mucus to prevent sperm from reaching the egg.

5. Ethinyl estradiol and levonorgestrel (Yuzpe method): This method involves taking two doses of combined oral contraceptives containing ethinyl estradiol and levonorgestrel 12 hours apart. It works by preventing ovulation and thickening cervical mucus to prevent sperm from reaching the egg.