Family doctor

Overview

• Spermicides are designed to kill sperm and stop conception
• Spermicides are mainly used to increase the effectiveness of other contraceptive methods
• They are often used in conjunction with condoms or a diaphragm
• They have a high failure rate of up to 30 percent when used alone
• There is evidence they can help to prevent some sexually transmitted diseases
• Spermicides are available as gels, pessaries, cream or foam

What are spermicides?

Spermicides are a range of chemical substances which are used to kill sperm.

They are one of the oldest methods of contraception but these days are mainly used in conjunction with other methods such as condoms or a diaphragm.

The spermicides form a temporary barrier against conception and can immobolise sperm.

Most spermicides use the active ingredient nonoxynol-9 to destroy sperm.

Studies show a wide range of effectiveness, with failure rates ranging from less than one to over 30 pregnancies per 100 woman years. A failure rate of 20 percent is often quoted.

Advantages

• They are free from any major health risks
• They help to increase the effectiveness of other methods
• Spermicides are easily available without a prescription
• They provide some extra lubrication
• There is some evidence they may help to kill sexually transmitted disease organisms such as gonorrhoea, chlamydia, and genital herpes (but should not be relied upon to do this!)

Disadvantages

• A higher failure rate than other commonly used contraceptive methods
• Are thought to be messy
• They can be inconvenient to use at the time of intercourse
• Can take time to become effective and effectiveness is reduced one hour after insertion
• May cause some vaginal irritation

Risk factors

There is some debate that the use of spermicide in early pregnancy could have a harmful effect on the foetus.

One study found an increase in birth defects in women who used spermicide in early pregnancy, but other studies have failed to find any link.

Studies have shown frequent use of spermicides (more than 4 times a day) can cause minor vaginal irritation.

How are they used?

Spermicides come in a range of products. There are gels, foams, pessaries and creams available.

They should be inserted into the vagina just before intercourse. Their effectiveness is reduced one hour after insertion.

The spermicide melts into a liquid inside the vagina and forms a chemical barrier between the sperm and the cervix.

It is important to follow the directions on the product label so it is used correctly.

Foams are considered more effective than creams or gels because they are better distributed around the vagina.

Pessaries may need to be inserted up to 15 minutes prior to sexual intercourse for them to melt and be effective.

A new application is necessary for each act of intercourse, and douching should be avoided for at least eight hours after intercourse.

Future trends

New chemical spermicides are being investigated to determine whether they can effectively destroy sperm.

New spermicides are coming available which provide protection for 24 hours, rather than just one hour.

Studies of diaphragms which have been pre-coated with spermicide are underway.

Vaginal rings which release the nonoxynol-9 chemical over one month or more are also being studied.

Getting help

Your local Family Planning clinic or your doctor will be able to advise you on methods of contraception.

* Spermicides are not a recommended method of contraception and should only be used in association with other contraceptives.