contraceptionImages (Click to view larger image)
contraception , family planning , prevention of pregnancy
Sexually active couples may be able to prevent unwanted pregnancies. The decision to prevent pregnancy can arise from personal situations or medical conditions. Birth control works by preventing the sperm from fertilising an egg or by preventing implantation of the fertilised egg. There are many options for contraception, or contraception. Each method of contraception has different failure rates, side effects, convenience factors, health risks, partner involvement, and cost and availability issues. A doctor can help a couple decide which method is right for them.
Natural family planning methodsMany couples choose a natural method of family planning because of religious or personal beliefs. These methods include:
- withdrawal, or coitus interruptus, in which the penis is withdrawn from the vagina before the male ejaculates. This method has a high failure rate because a small amount of sperm may be introduced into the vagina before the penis is removed.
- douching after sex. This method has a high failure rate.
- the rhythm method. For this type of family planning, a woman avoids sex during the middle of her menstrual cycle, which is when the release of an egg, or ovulation, occurs. This method has a fairly high failure rate. It should only be used by women who have regular, predictable cycles. The pregnancy rate with the rhythm method is about 40% yearly.
- breast-feeding. Breast-feeding is not entirely reliable in preventing pregnancy. A backup method of contraception, such as a condom or hormones, should be used during the time a woman is breast-feeding.
Traditional barrier methods Barrier methods use physical or chemical blocks to prevent sperm from fertilising the woman's egg. These methods include:
- condoms, or synthetic sheaths. Male condoms cover the penis and prevent semen from being deposited within the vagina. They also create a barrier against sexually transmitted diseases, such as HIV. Female condoms cover the external genitals and walls of the vagina. The failure rate for condoms is about 1%, although the rates are higher for adolescents.
- vaginal spermicides, which kill the sperm in the vagina. Sperm-killing chemicals are applied using jellies, foams, creams, films, or suppositories. Spermicides have a high failure rate of about 20%.
- a diaphragm, or flexible rubber cap that is placed within the vagina. It covers the cervix and should be used with spermicidal jelly. It is placed in the vagina at least 20 minutes before ejaculation and left in the vagina for 6 to 8 hours after ejaculation. A cervical cap, which is smaller than a diaphragm, is another barrier method that covers the cervix. The main advantage of a cap is that it can be left in place for 48 hours and does not require additional spermicide application for repeated acts of intercourse.
HormonesFemale hormones in various combinations can be used to prevent pregnancy. These combinations include:
- birth control pills, or oral contraceptives, which prevent ovulation by changing hormone levels in the body. A combination of oestrogen and progesterone in small amounts are taken each day. As long as the pill is taken as directed, pregnancy can be prevented. Failure rates are 2% to 3%. Pregnancies usually result when a woman forgets to take the pill as directed or uses expired pills.
- progesterone-only contraception pills, or the "minipill." These pills do not have oestrogen but still prevent pregnancy. The failure rate is 3% to 7%.
- progesterone implants, which are small plastic rods that are inserted beneath the skin. The implants supply small daily doses of hormones to prevent pregnancy. The contraception effect lasts 5 years. A minor procedure is performed by a doctor after 3 to 5 years (depending on which system is used) to remove the rods. This method has a very low failure rate of less than 1%.
- 1: Implanon - single rod lasting 3 years.
- 2: Non-plant - 6 rods lasting 5 years.
- injections of synthetic progesterones, which are hormones given every 3 months. During the 90 days of contraception, the failure rate is less than 1%.
- injections of progesterone and oestrogen in combination, given once a month. This method has a failure rate of less than 1%.
Intrauterine devices Intrauterine devices, or IUDs, are inserted into the uterus to prevent implantation of the fertilised egg. They have been associated with an increased risk of sexually transmitted disease and pregnancy outside the uterus, or ectopic pregnancy. The failure rate is about 2% to 3%.
SterilisationSurgery can be performed on a man or woman to prevent pregnancy. A vasectomy in a male involves cutting and tying off the tubes that carry sperm. A tubal ligation in a woman involves cutting and tying off the tubes that carry eggs from the ovaries to the uterus. Surgical removal of the uterus, or hysterectomy, also causes sterilisation but is not routinely used as a birth control method unless other problems are present. These methods are highly effective but often irreversible. All surgery carries a risk of bleeding, infection, and allergic reactions to anaesthesia.
Emergency contraceptionEmergency contraception involves birth control that is given after intercourse has already taken place. If there is unprotected sex, high-dose oral contraceptives can be given over a 24-hour period, within 72 hours of the unprotected intercourse. Another method uses an intrauterine device, or IUD, placed into the woman's uterus within 5 days of unprotected sex.
AbstinenceAbstinence, or the avoidance of sexual intercourse, is the only completely effective way to prevent pregnancy. However, this method might not be a desired option due to a couple's personal beliefs and sexual needs.
Reviewer: eknowhow Medical Review Panel
Editor: Dr John Hearne
Last Updated: 12/06/2005
Potential conflict of interest information for reviewers available on request