Final answer:
Progesterone and synthetic progestins are used in birth control to prevent ovulation and modify cervical mucus, making them effective contraceptives. Oral pills, injections, and implantable devices like Implanon are common delivery methods. There is a slight risk increase for blood clots with combined pills but not with progesterone-only pills.
Step-by-step explanation:
Progesterone is a female sex hormone primarily secreted by the ovaries, which plays a crucial role in maintaining a successful pregnancy. In the context of contraception, high concentrations of progesterone or synthetic progestins are used in birth control methods due to their ability to inhibit ovulation. This is often achieved through daily oral contraceptive pills, which deliver synthetic progestins that prevent the release of eggs from the ovaries and cause changes to the cervical mucus, making it less conducive for sperm to join an egg. Hormonal contraception can also involve other delivery methods such as injections, patches, or implantable devices like the Implanon rod, which releases progestin to prevent pregnancy.
Due to these contraceptive methods, particularly the combined pill containing both estrogen and progesterone, there is a slightly increased risk of blood clots, with a reduced risk of ovarian and endometrial cancers. The progesterone-only pill, however, does not increase the risk of blood clots, but may lead to irregular menstrual periods. It's important to note that hormonal methods are only available for individuals with a uterus and ovaries, and there are considerations for when to start these methods postpartum to avoid increased risk of clots.
Moreover, hormonal contraceptives are contrasted with humoral stimuli, which involve bodily fluids, while hormonal stimuli pertain to the hormones secreted directly into the bloodstream having a systemic effect.