Fertilization occurs when a man's sperm penetrates a woman's egg, as a result of sexual intercourse. Afterwards, if conditions are favorable, the fertilized egg will implant itself in the uterus with a resultant pregnancy. Contraception is designed to prevent sperm from meeting the egg, to prevent the fertilized egg from implanting itself and, ultimately, to prevent pregnancy.
Condoms, diaphragms, contraceptive sponges and cervical caps are some of the most popular barrier methods of contraception. They work by creating a barrier, preventing the sperm from even reaching the egg.
Condoms are made from a variety of materials including latex, polyurethane and animal tissue. Apart from those made from animal tissue, condoms protect against sexually transmitted diseases. They are very accessible and inexpensive.
As for the diaphragm, sponge and contraceptive cap, they must be used with spermicide. To be effective, they must be inserted before intercourse and must remain in the vagina for several hours after intercourse. Furthermore, women should refrain from washing the vaginal area immediately after intercourse to allow the spermicide sufficient time to destroy all the sperm. The diaphragm must be properly fitted and adjusted to the size of the cervix by a health care professional during a gynecological examination.
This method is based on tracking fertility signs (ex. cervical mucus monitoring) and taking daily basal body temperature readings. By being in tune with her menstrual cycle, hormonal changes and ovulation time, women and their partners can choose whether or not they wish to conceive. Since no hormones or potentially irritating products (ex.: latex, spermicide) are used, this method is free of adverse effects. Furthermore, it does not interfere with breastfeeding. It does, however, require a great deal of discipline.
This method of contraception provides effective protection if, and only if, each of the following conditions are met:
Once one of the conditions is no longer true, protection decreases. If the woman does not wish to become pregnant, she should, at this point, choose another method of contraception.
In this category are oral contraceptives, also known as birth control pills or "the pill". Oral contraceptives contain two types of hormones, namely estrogen and progestin, that prevent ovulation. In addition to being very effective, hormonal contraception offers many other advantages:
If there is an intolerance or contraindication to estrogen, a progestin-only pill does exist (mini-pill). This contraceptive is also used by women who are breastfeeding, since it does not affect milk production as much as estrogen.
For those who find it too bothersome to take an oral contraceptive on a daily basis, there are other choices that are just as effective. These include the transdermal contraceptive patch - changed once a week, the contraceptive vaginal ring - changed every month and the injectable progestin contraceptive - administered every 3 months.
Medications such as certain anticonvulsants, antituberculotics, antidiabetics and antibiotics can reduce the effectiveness of hormonal contraceptives. It is therefore important to use additional contraception or change your method of contraception when using any of these medications.
There are two types of IUDs: copper and progestin. Both hinder sperm mobility and make the uterus an unfavourable area for implantation. The progestin IUD can, in some women, prevent ovulation. IUDs must be inserted in the uterus by a healthcare provider. They are more commonly used by women who have already had a child.
This type of contraception is used when another method has failed. These include the emergency contraceptive pill (ECP), known as the "morning after pill" (taken orally) or the copper intrauterine devices (IUD). The ECP may be used up to 5 days after unprotected intercourse. It is more effective when taken as soon as possible - ideally 0 to 72 hours after having had unprotected intercourse. It can be obtained after consultation with a pharmacist or physician. This treatment may cause nausea and vomiting. If needed, drugs to prevent vomiting can be taken before the ECP. If vomiting occurs within the first 2 hours after taking the ECP, it is important to take another dose. The ECP reduces the likelihood of pregnancy by approximately 75 to 90%. In some women, it can precipitate or somewhat delay menstruation. It does not interfere with an established pregnancy and does not harm the fetus.
The intrauterine device can be useful as an emergency contraception method up to five days after unprotected sexual intercourse or within five days after the expected date of ovulation. It is even more effective at reducing the risk of pregnancy than the ECP. The IUD must be inserted by a physician and can be removed immediately following the end of the next menstrual period or left in place as a form of contraception.
Emergency contraception must not replace normal contraception since it is not as effective as the other methods, when used properly.
For more information:
The Society of Obstetricians and Gynecologists of Canada
Sex and U
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