Contraception

How does it work?

Contraception means prevention of pregnancy and contraceptive methods work in a variety of ways. They may prevent the sperm from fertilising the ovum, prevent ovulation or change the endometrium so the fertilised ovum can’t implant.

Different people have different attitudes towards contraception. They may decide not to use contraception for cultural, religious or lifestyle reasons but most people want to plan when they have children and the number of children they would like to have.

Methods

Combined oral contraceptive pill   Progestogen only pill

Copper IUD   DMPA - Depo Provera, Depo Ralovera

Female condom    Male condom

Male sterilisation    Female sterilisation

Implanon   Mirena®    Diaphragm

Vaginal ring

How the different methods work:

• stopping the release of eggs (oral contraceptive pills, hormone injection, vaginal ring)
• stopping sperm getting into the male ejaculate (vasectomy)
• stopping the egg and sperm meeting by:
   - using a barrier (condom)
   - thickening the mucus at the cervix to stop the sperm getting through
   - blocking the tubes between the ovary where the eggs are produced and the uterus (female sterilisation)
   - being toxic to the eggs and sperm (copper IUD)
• making the lining of the womb too thin for the fertilised egg to embed

Overview of methods

The different methods of contraception can be described in different ways.

How long do contraceptives last?

This can range from a permanent method, a long-acting method (three, five or ten years), a medium acting method (four to twelve weeks) or a short acting method (daily).

How are they used?

Contraceptives include:

• a pill taken by mouth
• an injection or implant under the skin
• an intrauterine device that is inserted into the uterus
• a hormone vaginal ring or a diaphragm that the woman inserts into the vagina
• a condom that covers the male penis or the inside of the vaginal walls

Some women feel more in control by taking a pill each day, while other women prefer a method that they can forget about for most of the time.

How good are they at preventing a pregnancy?

There are a number of safe and effective methods of contraception available in Australia and it is important to find the method that is best for you. Learning about each method may help you make your decision. Only you can decide what is best for you.

There is no method that is 100 per cent effective. The effectiveness of different methods can be measured by ‘perfect-use’ where rules of the method are rigorously followed, and (if applicable) the method is used at every act of intercourse. The failure rates in practice (typical use) are higher than perfect-use rates for a variety of reasons. A person might:

• be given the incorrect instructions about the how to use the method (eg. starting the pill at the wrong time)
• make mistakes when using the method (eg. not use a condom properly)
• forget the requirements for using the method (eg. being late for a contraceptive injection)

For more information, see the Family Planning Alliance Australia Efficacy of contraception methods fact sheet.

’Typical use’ is the rate that should be considered when comparing methods.

Efficacy (Perfect Use/Typical Use)

Reference: Trussell J. Contraceptive failure in the United States. Contraception 2011; 83(5):397-404.

Cost

Some methods have a regular cost and some an ‘upfront’ cost when it is first used and then a low cost after this. It is wise to compare the methods by looking at the cost over time. The cost needs to be weighed against how effective it is. If a method is not very effective there is a much greater risk of pregnancy which will cost a lot more! For method-specific costs, refer to the 2014 Choice magazine Contraceptive buying guide.

Menstrual bleeding with contraception

• Some methods do not affect your normal cycle at all (condoms, fertility awareness, diaphragm)
• All contraceptive methods that contain a hormone will affect your normal cycle
• The bleeding that occurs with hormones is not a true period (ie. not under the control of your natural hormones)
• Bleeding when taking hormones is called a withdrawal bleed when it happens regularly (such as on the oral contraceptive pill)
• Irregular bleeding with hormones is called break-through bleeding (this suggests that the hormones are not controlling the bleeding pattern)
• You may choose a particular method because the bleeding pattern may suit you and your lifestyle
• Some methods are particularly recommended for women with heavy periods as they can reduce the bleeding (Mirena IUD)

Your questions answered