Contraception: types and methods
Contraception consists of artificial and natural methods for controlling fertility.
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Contraception allows people to choose whether and when to have children. There are several types and each works differently (see Using contraceptives). Nearly all types, apart from the male condom and male sterilization, are designed for use by women.
Most contraceptives, apart from condoms, are supplied by your doctor, who considers your age, medical history, and sexual lifestyle. No contraceptive is entirely free from risk. Some types may not be suitable for you, while others have side effects that you must weigh against the benefits. You may need to change your contraceptive as you grow older, after having children, or if you alter your sexual lifestyle. It is important that you are happy with your contraceptive. Even if your doctor has recommended a particular type, do not accept it if you have doubts about it.
Barrier methods
Barrier contraceptive methods include diaphragms, condoms, and cervical caps. They act by preventing sperm from entering the uterus and reaching the egg. Male condoms cover the penis, female condoms line the vagina, and caps and diaphragms cover the cervix. Barrier contraceptives do not disrupt normal body functions or affect fertility, but they are unreliable if not used correctly and can also affect the spontaneity of sex. Some people may be allergic to the material from which condoms are made. When used correctly, condoms are an effective method of preventing unwanted pregnancy. Condoms may also protect women from cancer of the cervix by reducing the risk of infection with human papillomavirus. The male condom is the only contraceptive method that also protects users and their partners from sexually transmitted infections (see Safe sex). Condoms may also be used for protection when one partner has a longstanding infection such as HIV (see HIV infections and AIDS).
Hormonal methods
Hormonal contraceptives alter the hormone balance in a woman's body to prevent conception. They may be taken orally in the form of the combined pill or the progestogen-only pill. Hormones may also be injected into a muscle, implanted in a flexible rod under the skin, or administered via a hormone-containing intrauterine device (known as an intrauterine progestogen-only system or IUS). These methods do not interrupt sexual activities, but they can cause side effects or health risks in some women. If you stop using them, it may take a few months for your fertility to return. Oral contraceptives may not be reliable after a bout of vomiting or diarrhoea, and you should use other methods in this situation. Certain drugs may interact with oral contraceptives so if you are taking an oral contraceptive you should tell your doctor in case it interacts with other medication. Your pharmacist should be able to advise you about possible interactions with over-the-counter medications.
Combined oral contraceptive pill
This type of pill (COC), containing both oestrogen and progestogen, is highly reliable. There may be side effects, such as changes in weight and mood, but these usually disappear after the first few months of use. The COC pill lowers the risk of cancer of the ovary but increases the risk of some other disorders. It can cause a slight rise in blood pressure, so you may be advised not to use it if you have a family history of high blood pressure (see Hypertension) or a family history of high blood lipids (see Hypercholesterolaemia). The COC pill also causes blood to clot more readily, increasing your risk of stroke and heart attacks (see Myocardial infarction). The risk is substantially raised if you are over the age of 35 and smoke. The COC pill may also not be advised if you are very overweight or have a parent or sibling who has had deep vein thrombosis.
Progestogen-only pill (POP)
This type of contraceptive pill contains only progestogen and does not carry the health risks of the COC pill. The traditional POP is less effective than the COC pill and must be taken at the same time each day to be reliable. It often causes lighter periods but may also make your cycle irregular. However, its effect on menstruation does not alter its effectiveness as a contraceptive. There may be other side effects, such as acne and breast tenderness, but these should last only a few months. There is also a small risk of ovarian cysts or of an ectopic pregnancy if you conceive while taking it. A new type of POP is available that works by inhibiting ovulation and is more effective than traditional POPs. Like traditional POPs, it may cause menstrual irregularities, acne, and breast tenderness.
Injections and implants
Progestogen can be given as an injection or an implant; both provide reliable long-term contraception. They are useful if you do not want to have children for some years or at all or if you forget to take pills. Initially, these may make your periods irregular or heavier. You may also gain weight. After the first period, most women stop menstruating.
Intrauterine progestogen-only system (IUS)
The IUS is similar to an ordinary intrauterine device, or IUD but, unlike an IUD, it contains progestogen. The IUS consists of a T-shaped plastic frame impregnated with progestogen, which is released slowly and continuously. It prevents contraception by thinning the lining of the uterus and thickening the cervical mucus. It may also suppress ovulation in some women, although most continue to ovulate. The IUS is an extremely reliable form of contraception. It starts to work immediately if it is fitted during the first 7 days of your menstrual cycle. If it is fitted at any other time, additional contraception is necessary for the first 7 days. The IUS lasts for 5 years. After it is removed, fertility usually returns quickly. The IUS makes periods lighter and less painful after the first three months of use. For this reason, it can be useful for women with heavy periods or for those nearing the menopause. It may cause side effects such as irregular periods and breast tenderness but they usually wear off after a few months. The IUS shares many of the disadvantages of the IUD, such as the rare risk of being expelled from the uterus or of piercing the uterine wall and causing inflammation of the abdominal lining (see Peritonitis).
Mechanical methods (IUDs)
Intrauterine devices (IUDs), also known as coils, are devices that are inserted into the uterus by a doctor. They are made of plastic coated with copper, and have threads that protrude into the vagina so the user can check that her IUD is still in place.
IUDs give immediate protection and last for several years. However, they may be difficult to insert in women who have never been pregnant and may increase your susceptibility to certain infections (see Pelvic inflammatory disease). Rarely, an IUD may be expelled from the uterus, or may pierce the wall of the uterus and cause peritonitis. The IUD does not affect hormones or ovulation, but it may worsen heavy or painful periods (see Menorrhagia, and Dysmenorrhoea).
Natural methods
Natural birth control involves working out when you are fertile and avoiding intercourse at those times. It has no side effects, but can disrupt the spontaneity of sex and should not be used without training. It also requires that you have a regular menstrual cycle. There is a fertility monitoring kit available for home use. Natural birth control works best if you feel that you could accept an unplanned pregnancy.
Surgical methods
Surgical contraception, or sterilization, is an operation that makes you infertile. This surgery can be carried out on men (see Vasectomy) or women (see Female sterilization). Since the operation is considered permanent, it is suitable only for those who are sure that they do not want children. The operations have low failure rates, of about 1 in 1,000 men and 5 in 1,000 women.
Male sterilization is not immediately effective. The seminal vesicles (sacs that hold semen) still contain sperm after the operation, and a condom must be used until semen analysis shows that no sperm are left. Female sterilization is immediately effective, but slightly increases the risk of ectopic pregnancy should it fail for any reason.
Emergency methods
Emergency contraception is used to prevent pregnancy if you have unprotected sex or if your contraception has failed. It consists of taking a single dose (comprising two pills) of the hormone levonorgestrel as soon as possible after intercourse, ideally within 12 hours but no later than 72 hours after intercourse. These pills can be obtained from your doctor, or over the counter without a prescription if you are over 16.
BMA Complete Family Health Guide
Copyright © 2005 Dorling Kindersley
Posted 30.06.2010
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