Barrier methods of contraception include condoms, diaphragms and cervical caps. They form a physical barrier which prevents the man’s sperm from reaching and fertilising the woman’s egg.Condoms
- There are two kinds of condom available, male and female. Men wear condoms over the penis during intercourse. The condom traps the sperm after ejaculation and prevents it from entering the vagina. Male condoms are about 98% effective in preventing a pregnancy. This means that only about 2 in every 100 women would get pregnant in a year if the male condom was used as the method of contraception. Male condoms are widely available from pharmacies, supermarkets, vending machines or may be obtained free from family planning clinics.
Female condoms are worn by the woman during intercourse. The female condom lines the vagina and works in the same way as the male condom by trapping sperm. If used according to instructions the female condom is 95% effective. This means that 5 women in 100 will get pregnant in a year if the female condom was used as the method of contraception. Female condoms are not as widely available as male condoms, but they may be obtained from pharmacies and are free from family planning clinics.
As there is no direct contact between the penis and vagina and no exchange of body fluids during sexual intercourse, condoms are the only methods of contraception that also help protect men and women from sexually transmitted infections, including HIV.Diaphragms and cervical caps
– Diaphragms and cervical caps are round, flexible, rubber or silicone devices that are inserted into the vagina before intercourse to prevent sperm from entering the uterus through the cervix.
A cervical cap is smaller than a diaphragm and needs to be positioned directly onto the cervix. Cervical caps are mainly used by women who find it difficult to keep a diaphragm in place. Diaphragms and cervical caps must always be used with a spermicide, a gel or cream that kills sperm. The diaphragm or cap must be left in place for at least 6 hours after intercourse to ensure that all the sperm have been killed.
Diaphragms and cervical caps are 92-96% effective if used according to instructions and together with a spermicide. This means that between 4 and 8 women in 100 will get pregnant in a year using these forms of contraception.
A doctor or family planning nurse must measure the size of the vagina in order to select the right size of diaphragm or cervical cap. They will also show the woman how to insert the diaphragm or cervical cap and how to apply the spermicide correctly. Hormone methods
Hormone methods of contraception work by changing how a woman’s body responds during her menstrual cycle. All hormone contraceptives are free and available from a doctor or family planning clinic. The hormone method chosen will depend upon the woman’s medical history, age, lifestyle and personal preference.
The types of hormone contraception available include: The pill or oral contraceptives –
There are two types of oral contraceptive pill available. One is the 'combined pill' which contains two types of hormones, a progestogen and an oestrogen. The combined pill works by stopping ovulation, the process by which an egg is released from the ovaries into the uterus. Combined pills also thicken the mucus in the cervix, making it difficult for sperm to pass through into the uterus to fertilise the egg. Combined pills also thin the lining of the uterus making it more difficult for a fertilised egg to stay in the uterus. If the combined pill is taken according to instructions it is over 99% effective. This means that less than one woman in 100 will get pregnant in a year using this method.
The second type of oral contraceptive pill is called the ‘progestogen-only pill’ or 'mini pill' which contains only one type of hormone, a progestogen. The progestogen-only pill works by thickening the mucus in the cervix and by thinning the lining of the uterus. With the exception of a pill called Cerazette, progestogen-only pills do not depend on preventing ovulation. If the progestogen-only pill is taken according to instructions it is over 99% effective. This means that less than one woman in 100 will get pregnant in a year using this method.
Oral contraceptive pills must be taken each day, and they are most effective if the pill is taken at the same time each day. If a pill is forgotten or taken late then it may no longer be effective and the woman may not be protected against becoming pregnant.The patch
– The contraceptive patch, Evra, contains an oestrogen and progestogen. It works in the same way as a combined pill, but has the advantage that it only needs to be applied once a week for three weeks each month. It is as reliable as the combined pill.Vaginal ring
- The contraceptive vaginal ring, Nuvaring, is a flexible plastic ring that releases the oestrogen and the progestogen over a period of 3 weeks. Once the ring has been inserted it is left in the vagina continuously for 3 weeks. It is then removed and replaced one week later by a new ring. If the vaginal ring is used correctly and according to instructions it is over 99 per cent effective. This means that less than one woman in 100 will get pregnant in a year using this method.Injection
– A progestogen, either norethisterone or medroxyprogesterone, is injected once every 8 or 12 weeks. The hormone is released slowly during that time, stopping ovulation, thickening cervical mucus and thinning the lining of the uterus. Contraceptive injections are over 99% effective, which means that less than 1 woman in a 100 will get pregnant in a year. An injection has the advantage that the user does not have to remember to take the pill each day. Its disadvantage is that it cannot be removed once it has been injected and the user will have to continue with this method of contraception for as long as its effects last.Implant
– These are small tubes containing a progestogen, etonogestrel, which are inserted under the skin once every 3 years. The hormone is released slowly into the blood stream over that period. Implants are 99% effective and have the advantage that the user does not have to remember to take or use other forms of contraception.Intra-uterine system
– This is a T-shaped intrauterine device that slowly releases a progestogen, levonorgestrel. It is replaced every 5 years. It works by increasing the thickness of cervical mucus and by thinning the lining of the uterus. Most women continue to ovulate while using the system. It is 99% effective and, like other long term contraceptive methods, has the advantage that the user does not need to remember to take or use other forms of contraception.
Mechanical methodsIntra-uterine devices
– An intra-uterine device or IUD is a small plastic device carrying thin copper wire that is inserted into the uterus. The device has 1 or 2 soft threads at its end that allows the IUD to be withdrawn from the uterus when it is no longer required or needs to be replaced. IUDs work by preventing sperm from surviving in the uterus and by preventing a fertilised egg from implanting in the uterus. IUDs are over 99% effective. An IUD needs to be fitted by a doctor or family planning nurse and replaced every 5 to 10 years depending on the device.