SPERMICIDES
Average Failure Rate: 26%
Spermicides prevent pregnancy by
killing sperm so that none can reach and fertilize an egg. Scientific
studies of spermicides show failure rates ranging from zero to
50% for typical users. For effective contraception, correct timing
and placement are crucial. The spermicide must be used every
time intercourse occurs and before the penis is placed anywhere
near the vagina. All spermicides must be reapplied if intercourse
is repeated. Spermicides have been known to cause allergy and
irritation in many women. Some benefits of spermicides are that
they may be purchased without a prescription, cost relatively
little, and may guard against some types of infection.
However, spermicides do increase the risk of painful urinary
tract infections in women.
WARNING: Spermicides containing nonoxynol-9 were once thought to help prevent HIV infection, but newer studies show an increased risk because the chemical can irritate the vagina, facilitating infection. In a recent study involving African prostitutes, 15% of prostitutes using a combination of condoms and nonoxynol-9 became infected with HIV, while 10% of the prostitues using condoms alone became infected. Consequently, spermicides are no longer being recommended for HIV prevention.
Several types of spermicides are available. Spermicidal creams and jellies are designed for use with a diaphragm or cervical cap, but they can be inserted directly into the vagina with a special applicator. One advantage of creams and jellies is that they can be used for added lubrication, often needed with a condom. Contraceptive foams come in a small can with a plunger-type applicator, and are inserted in the same way as many of the creams and jellies.
Contraceptive films, thin spermicidal squares, are placed over the cervix before intercourse. These are not as messy as creams, jellies, or foams, and the film dissolves completely in the vagina. Suppositories, small waxy spermicidal inserts, are inserted by hand or with an applicator.
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