<prompt> Main mechanism of combined OCP?Feedback inhibition of pituitary causing of LH surgeChange in camicalmuesDecreased motility and secretion of the fallopian tubePrevent amputation  <response>: Ans. A. Feedback inhibition of pituitary causing of LH surgeThe estrogen provides a negative feedback on the release of FSH and LH by the pituitary. The progestin inhibits LH release. Both synergize to inhibit MID cycle LH surge. As a result, ovulation does not occur. Interference with ovulation is the most common pharmacologic mechanism for preventing pregnancy 