How does birth control work?
There are many different types of birth control: INTRAUTERINE DEVICE (IUD) A small device inserted into the uterus to prevent conception. It prevents implantation into the side of the uterus. IUDs have a failure rate of between 1 and 6 pregnancies per 100 women. BARRIER METHODS (condoms, diaphragm and the cap) The male condom is a penile sheath, and acts by catching and collecting the semen so it doesn’t get into the vagina. The female condom is a thin silicone membrane which partly or completely covers the outside of the female genitals, acting as a barrier. Diaphragms and caps are placed inside the vagina to cover the entrance to the uterus and stop sperm getting into the womb. They must be fitted to the user by a trained health professional. HORMONAL CONTRACEPTIVES (the pill) Involves taking an oral contraceptive pill regularly and diligently. Combination pills contain estrogen and progesterone, mini-pills contain progesterone only.
There are various methods of birth control, and they work in different ways. Some methods provide physical barriers that prevent sperm from reaching eggs. Others use hormones to prevent conception. A woman can have her tubes tied (tubal ligation) which will prevent sperm from reaching an egg, but that is a permanent form of sterilization. A man can have a vasectomy which prevents ejaculation of sperm during intercourse, and that can be reversed depending on the procedure used when the vasectomy is performed. Probably the least reliable method is to abstain from intercourse when the female is ovulating (releasing an egg each month). That is the the only time a woman can conceive, but timing is everything with that method, and we can’t always count on that being absolutely precise.
When you’re pregnant, your body releases certain hormones to prevent ovulation. This is important because if say you are carrying a 3-month old fetus, and you ovulate and the ovum is fertilized. It would be extremely dangerous to carry multiple fetuses at different gestations, especially during birth of the oldest fetus. This is a very effective mechanism. The hormones in oral contraceptives are analogous and work the same way as the hormones released during pregnancy. This is why birth control pills are so effective when taken correctly. This is also why you will have lighter, more regular periods. For more information, check out the link.
