State the pharmacological effects of progestin-only contraceptives.

1. Inhibition of ovulation: Progestin-only contraceptives work by suppressing the release of an egg from the ovary, preventing fertilization.

2. Thickening of cervical mucus: Progestin-only contraceptives can make the cervical mucus thicker, making it more difficult for sperm to reach the egg.

3. Changes in the endometrium: Progestin-only contraceptives can alter the lining of the uterus, making it less hospitable for a fertilized egg to implant and grow.

4. Inhibition of sperm transport: Progestin-only contraceptives can slow down the movement of sperm through the fallopian tubes, reducing the chances of fertilization.

5. Reduction in menstrual bleeding: Progestin-only contraceptives can lead to lighter periods or even stop menstruation altogether in some women.

6. Regulation of menstrual cycles: Progestin-only contraceptives can help regulate irregular menstrual cycles and reduce symptoms of premenstrual syndrome (PMS).

7. Decreased risk of certain cancers: Progestin-only contraceptives have been associated with a reduced risk of endometrial and ovarian cancers.

8. Treatment of certain medical conditions: Progestin-only contraceptives can be used to treat conditions such as endometriosis, polycystic ovary syndrome (PCOS), and menstrual disorders.