Question

Consider the hormonal regulation of oogenesis and ovulation, as well as hormonal feedback mechanisms onto the hypothalamus and pituitary gland. Please explain the hormonal action and feedback mechanisms that underlie how the birth control pill works as a hormonal contraceptive.

Answer 1

• Progesterone hormone is primarlly responsible for preventing pregnancy.
• The main mechanism of action include prevention of ovulation , they inhibit follicular development and prevent ovulation.
• Negative feedback of progesterone work at hypothalamus to decrease the pulse frequency of gonadotrophin releasing hormone, which in turn decrease in the secretion of FSH (follicle- stimulating hormone ) and luteinizing hormone (LH).
• If development of folicle is decreased , there will be decrease in estradiol level .
• The progesterone negative feed back and lack of estrogen positive  feedback on LH secretion stop on mid cycle LH surge.Absence of development of follicle and LH surge to release the follicle,leads to prevention of ovulation.
• Estrogen also has some effect with inhibiting follicular development because of its negative feedback on the anterior pituitary gland with slows FSH (follicle- stimulating hormone ) secretion;
• Another mechanism include progestrone inhibit the penetration of sperm into cervix and upper genital tract by cervical mucous thick.