A woman must use some method of birth control (contraception) if she is sexually active, fertile and physically able to become pregnant, and if she does not want to become pregnant. No method available today is considered to be 100% effective and offers perfect protection against sexually transmitted infections (sexually transmitted diseases, or STDs), except abstinence.
Barrier methods of contraception prevent pregnancy by physically preventing sperm from entering the uterus.
The most common forms of barrier contraception are:
- Condoms (male and female)
- Contraceptive sponge
- Diaphragm
- Cervical cap
The male condoms are one type of birth control that prevents pregnancy but also prevent the spread of sexually transmitted diseases (STDs) by preventing the infected area from coming into contact with the partner.
The female condom is a lubricated polyurethane (plastic) tube that has a flexible ring at each end with one end closed. The women insert the condom into her vagina before sexual activity begins so that the closed end of the tube covers the cervix, and the other end slightly covers the labia (lips on the outside of the vagina) so the condom blocks sperm from entering the womb.
The contraceptive sponge is a doughnut-shaped sponge, made of polyurethane foam and impregnated with the spermicide Nonoxynol-9. A woman before intercourse pushes the sponge up into her vagina (like a tampon) and the sponge then acts as a barrier in order to prevent sperm from reaching the cervix.
After intercourse, the sponge must remain in the vagina for at least 6 hours but never for more than a total of 30 hours because of the risk of toxic shock syndrome (caused by a type of bacteria when certain types of products, such as tampons, are left in place for excessive periods of time). Each sponge can be used only once and then thrown away.
The effectiveness of the sponge is 64% to 82%, and it can provide some protection against chlamydia and gonorrhea because of the spermicides, but the degree is unknown. Some women can experience irritation and allergic reactions.
The diaphragm is a soft flexible rubber cup shaped like a dome which is inserted into the vagina to blocks access to the cervix so that sperm cannot pass from the vagina into the uterus. It is only available with a prescription so a woman must see a health care practitioner to have a diaphragm properly fitted (they come in a range of sizes), and to learn proper insertion techniques.
A woman must insert the diaphragm no more than 4 hours prior to intercourse and prior to insertion cover the both sides and especially around its rim with spermicidal jelly, cream, or foam in order to form a tight seal around the diaphragm.
After intercourse, women must check that the diaphragm has not been dislodged and is still in the correct position and leave it in place for at least 6-8 hours after intercourse; after this time it should be removed. Each time intercourse is repeated, fresh spermicidal jelly or foam must be used.
The effectiveness of the diaphragm is 82%. Spermicides give a partial protection against Chlamydia and gonorrhea, but a diaphragm does not protect a woman from sexually transmitted infections.
There is an increased risk of urinary tract infections when a diaphragm is used because it increased pressure on the urethra. Also, some women may find spermicides to be irritating, but changing brands of spermicides may help.
The cervical cap is a small (1-1/2 inches or about 3 cm.), a thimble-shaped dome made of latex or silicone rubber (it is much smaller than a diaphragm). One small application of spermicide is placed inside the cap and a woman pushes the cervical cap up her vagina and into position over her cervix but unlike the diaphragm, it does not require fresh spermicidal jelly or foam before every intercourse as long is correctly positioned over the cervix. The cervical cap can remain in place for up to 48 hours.
Like a diaphragm, a cervical cap requires a prescription because a health care practitioner must determine the correct size and ensure that woman knows proper insertion techniques.
The effectiveness of the cervical cap is 80%. Spermicides give a partial protection against chlamydia and gonorrhea but a cervical cap does not protect a woman from sexually transmitted infections.
Some women may find spermicides to be irritating, but changing brands of spermicides may help.
Spermicides are a form of chemical contraceptive that works by killing sperm and they come in a wide variety of forms, including jellies, creams, foams, films, and suppositories. Often they are combined with barrier methods of contraception for greater effectiveness.
Spermicidal foams are more effective than creams or jellies because foam can be better distributed and it adheres better to the vaginal walls and cervix. Suppositories are placed in a woman's vagina 15 minutes before intercourse because they need to liquefy with vaginal moisture but the vaginal contraceptive film is placed 5 minutes prior to sexual intercourse.
Also, spermicidal suppositories must be unwrapped and inserted in the vagina and spermicidal creams, gels, and foam need to be deposited high up in the vagina near the cervix. After the intercourse, douching should be avoided for at least 8 hours.
The effectiveness of spermicides in preventing pregnancy varies from 70 to 90% and it 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 can partially protect against certain organisms that cause sexually transmitted infections, including chlamydia and gonorrhea, but they do not protect against the human Immunodeficiency virus (HIV) infection.
Spermicides are relatively inexpensive and they are available over-the-counter (OTC) without a prescription, but a buyer must know that lubricant jellies do not always contain spermicides.
