Hormonal contraception

Hormonal contraceptives use hormones to reduce the chance of pregnancy. They can prevent an egg from maturing or being released from an ovary. The release of an egg is called ovulation.

Some oral contraceptive pills contain hormones that inhibit the production of follicle-stimulating hormone (FSH). FSH normally stimulates eggs to mature in the ovaries. When its production is inhibited, eggs do not mature.

Injections, implants and skin patches also deliver hormones, including progestogens. These hormones can inhibit egg maturation and ovulation.

Hormonal contraception: Use and duration

The methods differ in how they are used and how long they act:

• Pills must be taken regularly.
• Injections are renewed at intervals.
• Implants can act for years.
• Skin patches are replaced regularly.

Effectiveness depends partly on using the method correctly and renewing or replacing it on time. Hormonal contraceptives do not protect against sexually transmitted infections.

Evaluating contraceptive methods

Choosing a contraceptive method means weighing how well it prevents pregnancy against its practical and personal advantages and limitations. A method that suits one person may not suit another.

Effectiveness in everyday use

A method’s effectiveness with typical use may be lower than its effectiveness when used correctly every time. In everyday life, a person may forget to use a method, use it incorrectly or use it at the wrong time.

Long-acting implants and intrauterine devices do not require action at each act of intercourse. By contrast, barrier methods depend on consistent, correct use, while fertility-awareness methods depend on identifying and responding to fertile times. These differences matter when considering how reliably a method can be used in a person’s circumstances.

Other factors in choosing contraception

Methods differ in duration and reversibility. Some provide contraception for a long time but can be stopped or removed; sterilisation is intended to be permanent. Methods may also differ in possible side effects, risks associated with a procedure, and convenience.

Condoms have an additional benefit: they reduce the risk of sexually transmitted infections as well as pregnancy. The most suitable choice depends on which benefits and limitations matter most to the individual.

Barrier contraception

Barrier methods of contraception physically prevent sperm from reaching an egg. They place a barrier in the path sperm would otherwise take through the reproductive system.

A condom is worn over the penis. It collects semen and keeps it out of the vagina, preventing the sperm in the semen from travelling towards an egg. A diaphragm is placed inside the vagina over the cervix, the opening to the uterus. It obstructs sperm from entering the uterus.

Barrier methods must be used correctly during intercourse. Incorrect use or failure of the barrier can allow sperm through, reducing the method’s effectiveness at preventing pregnancy.

Condoms also reduce the risk of sexually transmitted infections (STIs) by limiting contact with infected body fluids. Diaphragms do not provide the same protection against STIs.

Spermicidal contraception

Spermicides are chemicals placed in the vagina to kill or disable sperm. This reduces the chance that sperm will reach and fertilise an egg, making pregnancy less likely.

Spermicide can be used alone or with a barrier method, such as a diaphragm. The diaphragm blocks sperm from reaching the egg, while the spermicide acts on the sperm.

Spermicides must be used correctly to be effective. When used alone, they are generally less effective at preventing pregnancy than many other contraceptive methods. They do not protect against sexually transmitted infections and can cause irritation.

Intrauterine contraception

Intrauterine contraception uses a small device placed in the uterus to prevent pregnancy. There are two types: a non-hormonal copper device and a hormonal device.

Copper and hormonal devices

A copper device interferes with sperm, primarily preventing them from fertilising an egg. It may also prevent a fertilised egg from implanting in the uterine lining.

A hormonal intrauterine device releases a hormone called a progestogen. This thickens the mucus at the cervix, the opening to the uterus, making it harder for sperm to pass through and reach an egg. The hormone also thins the uterine lining.

Use of intrauterine contraception

An intrauterine device provides long-lasting contraception without requiring action during each act of intercourse. It must be fitted and removed by a trained health professional.

Neither type protects against sexually transmitted infections.