Final answer:
Oral contraceptive pills (OCPs) decrease the risk of ovarian cancer by inhibiting ovulation, reducing the number of menstrual cycles in which the ovarian epithelium is disrupted, thereby lowering the cumulative exposure to potential cell damage and mutation.
Step-by-step explanation:
OCPs, or oral contraceptive pills, are known to decrease the risk of ovarian cancer. This protective effect is primarily due to the inhibition of ovulation. Typically, OCPs contain a combination of estrogen and progesterone, which provides a constant hormone level that exerts negative feedback on the hypothalamus and pituitary gland. This feedback prevents the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH), hormones necessary for the maturation of follicles and the ovulatory surge, respectively. Without these events, ovulation does not occur.
Reduced lifetime ovulatory events are associated with a lower risk of ovarian cancer. In each menstrual cycle where ovulation occurs, the ovarian epithelium is disrupted and undergoes repair processes, which can increase the chance of aberrant cell growth and mutation. By reducing the frequency of these events with the use of birth control pills, OCPs reduce the cumulative exposure of the ovaries to this potential damage, thus decreasing the risk of cancer development.