Answer:
Oral contraceptives inhibit the secretion of gonadotropins by inhibiting the secretion of GnRH through a negative feedback mechanism.
Step-by-step explanation:
Most oral contraceptive pills have combined dosages of estrogen and progesterone or one of these hormones. The estrogen and progesterone are involved in negative feedback inhibition of gonadotropin-releasing hormone (GnRH). Presence of small dosages of estrogen and progesterone inhibit the secretion of GnRH and thereby, prevents the secretion of gonadotropins (LH and FSH).
FSH (Follicle-Stimulating Hormone) is required for maturation of follicles while LH (Luteinizing Hormone) is required for ovulation of mature follicle.
Hence, hormonal contraceptives prevent conception by preventing follicle development and ovulation due to the absence of gonadotropins (FSH and LH).