Contraception: the mini (progestogen only) pill
What is it?
The mini-pill or progestogen only pill (POP) is an alternative oral contraceptive to the combined pill. It contains a low level of progestogen, but does not contain any oestrogen. Brands available in Australia include Microlut 28, Microval 28, Locilan 28, Micronor, and Noriday.
How does it work?
It is possible to manufacture synthetic progestogens which mimic the natural hormone, progesterone, which is produced by your body every month mostly in the last 2 weeks of your menstrual cycle. Progestogen thickens the cervical mucus and makes the lining of the womb thinner. The thicker cervical mucus makes it very difficult for the sperm to get through to fertilise the egg and the thin lining of the womb makes it very difficult for an egg to implant even if it does manage to get fertilised. Progestogen can also inhibit the release of the egg from the ovary in some, but not all, menstrual cycles.
How effective is it?
The mini-pill is 96-99.5 per cent effective when taken in accordance with instructions.
What are the advantages?
Some of the advantages of the mini-pill are that it:
- may be suitable for women who cannot take the combined pill because of the oestrogen it contains (for example, those with cardiovascular disease or who have side effects from the oral combined pill, such as breast tenderness or fluid retention);
- is more suitable for smokers than the combined pill;
- lessens the risk of adverse side effects such as blood clots and high blood pressure associated with the combined pill;
- reduces the risk of pelvic inflammatory disease;
- can be used if you are breast feeding;
- can be started immediately after childbirth or abortion; and
- allows fertility to return without delay after you stop taking it.
What are the disadvantages?
Some of the disadvantages of the mini-pill are that it:
- must be taken at the same time every day;
- is less effective than the combined pill;
- can only be obtained on prescription;
- may result in spotting or irregular bleeding;
- does not protect against sexually transmitted diseases;
- is not recommended if you are obese, or have had an ectopic pregnancy; and
- should not be used in women with severe liver disease, malabsorption disorders, or those who have had blood clots in the lungs or legs or who have a blood clotting disorder.
How is it used?
The mini-pill is taken continuously on a daily basis, at the same time each day. There is no 7-day break or dummy pills as there are with the combined pill. If you forget to take a pill within 3 hours of the usual time you take it, or fail to absorb it due to vomiting or diarrhoea, you should use a barrier method of contraception, such as a diaphragm or condom for the next 2 to 14 days. Your doctor will be able to advise you.
Last Reviewed: 01 May 2002
