Hormones in human reproduction - EdexcelHormonal methods of contraception
Hormones regulate the menstrual cycle. This involves the monthly release of an egg from the ovary and the build-up and breakdown of the lining of the uterus.
Human fertilityThe ability to reproduce. is controlled by hormoneChemical messenger produced in glands and carried by the blood to specific organs in the body., so fertility can be controlled using hormonal forms of contraception.
The oral contraceptive, which is known as the pill, contains oestrogenA female sex hormone produced in the ovaries, which is responsible for puberty in girls and the regulation of the menstrual cycle. or progesteroneSex hormone produced by the ovaries and placenta. or a combination of both hormones. These hormones inhibit the production of FSHFollicle Stimulating Hormone. It stimulates oestrogen production and the growth of follicles (egg-sacs) in the ovary. It is secreted by the pituitary gland., and eggs cannot mature.
Oestrogen at low levels stimulates the release of eggs. However at high doses, oestrogen will inhibit FSH production. After taking the pill for a while, egg development and release will stop completely. If there is no egg available, there can be no baby. This is why contraceptive pills are so effective.
Benefits and risks
Oral contraceptives are more than 99% effective if taken correctly and can reduce the risk of certain cancers.
However, there are possible side effects, such as changes in weight, mood and blood pressure due to high levels of oestrogen. Modern pills contain much less oestrogen.
Contraceptive injections, implants or skin patches contain slow release progesterone to inhibit the maturation and release of eggs.