Barrier Methods of Birth Control (cont.)

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Barrier methods of contraception

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Barrier methods of contraception work by creating a physical barrier between sperm and egg cells so that fertilization cannot occur. The most common forms of barrier contraception are condoms (male and female), diaphragm, cervical cap, and contraceptive sponge.

Spermicides, a form of chemical contraceptive that work by killing sperm, are often combined with barrier methods of contraception for greater effectiveness.

While barrier methods of contraception generally do not have the side effects of hormonal contraceptives, some forms of barrier contraception (contraceptive sponges and condoms) may be obtained without a prescription and easily purchased over the counter at pharmacies.

The only medical contraindication to the use of barrier contraception is latex allergy (when using latex condoms). However, with the exception of male and female condoms that can provide protection against infection with sexually-transmitted diseases (STDs), most methods of barrier contraception are not effective in preventing STDs.

Spermicides

During sexual intercourse, hundreds of millions of sperm are normally released into a woman's vagina. The large majority of these sperm die. They die because of the vagina's unfriendly environment, which is acidic, and because the mucus in the cervix above the vagina acts as a selective filter for the sperm. Only about 1% of all the sperm released in an ejaculation successfully pass through the woman's vagina and cervix to reach the uterus (the womb). However, it only takes one sperm to fertilize the ovum (the egg) and to achieve conception.

Spermicides are a type of contraceptive agent that work by killing sperm.

Spermicides need to be in place in a woman's vagina before intercourse if they are to prevent viable sperm from reaching her uterus. Spermicides come in a wide variety of forms, including jellies, creams, foams, films, and suppositories. The active ingredient in essentially all spermicides is Nonoxynol-9. This is a detergent-like chemical that kills sperm.

Once placed inside the vagina, the spermicide melts into a liquid that coats the vagina in order to set up a chemical barrier between the sperm and the cervix. Spermicidal foams are more effective than creams or jellies. Not only is it possible to achieve a better distribution with foam, but foam adheres better to the vaginal walls and cervix.

Suppositories are solid or semi-solid and need to be inserted in the vagina 15 minutes before intercourse in order to liquefy with vaginal moisture.

Vaginal contraceptive film needs to be in place in the vagina about 5 minutes prior to sexual intercourse in order to liquefy and become effective.

Spermicides are like all other methods of birth control in that they must be used properly in order to prevent pregnancy. Each type of spermicide has a unique method of use. For example, spermicidal creams, gels, and foam need to be deposited high up in the vagina near the cervix. Spermicidal suppositories must be unwrapped and inserted in the vagina. Squares of spermicidal film should be inserted into the vagina with a woman's finger. It is important to follow the package's exact instructions.

A spermicide should be placed in the vagina prior to the man's penis getting anywhere near the vagina. It is a common mistake for a couple to wait too long before using the spermicide.

There are two basic concerns with any given spermicide. 1) How long the spermicide stays in the desired place; and 2) how long the spermicide is active in killing sperm. Therefore, the timing of spermicide use must take into account both of these factors.

In general, spermicides tend to be effective soon after their application. They can be inserted 15 minutes or more before intercourse. However, if there is a significant delay before intercourse (for example an hour), more spermicide must be added.

A fresh application of spermicide must also be used for each act of intercourse.

Douching should be avoided for at least 8 hours after the last intercourse.

The effectiveness of spermicides in preventing pregnancy varies from 70 to 90%. This depends on the amount of spermicide and how it is used, the timing of use prior to intercourse, and how well the instructions on the package are followed.

Spermicides should not be used as protection for the woman or man against sexually transmitted infections (sexually transmitted diseases, or STDs). While spermicides may be partially protective against certain organisms that cause sexually transmitted infections, including chlamydia and gonorrhea, they also do not protect against the human Immunodeficiency virus (HIV) infection.

The main objection voiced about spermicides is that they are "messy." A small percent (2% to 4%) of people may have an adverse reaction to Nonoxynol-9, which is experienced as an irritation or a burning sensation.

Spermicides, however, have some positive features. They are relatively inexpensive and they are available over-the- counter (OTC) without a prescription.

Note that some lubricating jellies also available over-the-counter do not contain spermicide and are not meant to be used as a form of birth control. It is important to check the information on the package to be sure that the product contains spermicide or that the word "contraceptive" appears on the label.

Medically Reviewed by a Doctor on 2/27/2014

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