What do oral contraceptive pills contain?
Generally, oral contraceptive pills contain progestin with or without estrogen. Progesterone and estrogen are naturally produced in the body, however, pills contain lab-made versions of them. Despite being synthetic, the hormones in the pills have the same effect as naturally-made progesterone and estrogen.
OCPs that only contain a version of progesterone are referred to as the “mini-pill.” Progesterone increases the thickness of the cervical mucus and thins the uterine lining. Thick mucus blocks sperm from entering the uterus, thus reducing the chances of fertilizing an egg. It can also prevent ovulation, or the release of an egg, further reducing the chances of pregnancy. On top of that, a thin uterine lining makes it harder for a fertilized egg to become implanted.
On the other hand, estrogen-containing pills offer additional effects. Estrogen is present in both sexes, albeit, in much higher amounts in women. It has positive effects on skin elasticity, bone health, and cholesterol levels. In women, estrogen plays a role in the development of secondary sex characteristics (e.g. breast development, body hair pattern) and the start of menstruation.
As part of OCPs, estrogen and progestin halt ovulation. Due to negative feedback mechanisms, luteinizing hormone (LH) and follicle-stimulating hormone (FSH) do not get released from the brain when there is enough estrogen and progesterone in the body. Without FSH and LH, the ovaries will not release a mature egg that can be fertilized.
How can oral contraceptives prevent ovarian and endometrial cancer?
As mentioned above, estrogen and progesterone influence various bodily functions in a woman’s body throughout her lifetime. Increased estrogen levels suppress the hormone FSH while progesterone suppresses the hormone LH. Essentially, without FSH and LH to stimulate the ovaries and endometrium, cell division is not sped up– which is one of the characteristics of cancer cells.