The Pill

The pill is the most common form of birth control in the UK. The term "the pill" usually refers to the combined oral contraceptive pill. It contains two synthetic versions of the hormones oestrogen and progestogen and is 99% effective in preventing pregnancy, if used correctly.

The pill is also considered to be an effective treatment for heavy or painful periods, premenstrual syndrome and endometriosis.

How does it work?

There are three steps involved in the process of preventing pregnancy with the combined contraceptive pill. Firstly, the pill stops the ovaries from releasing eggs, thereby preventing ovulation. Secondly, the vaginal fluid is thickened so sperm cannot reach the womb. Finally, the womb walls are made thinner so, if an egg were to be released, it would not be able to implant itself into the womb.

How effective is it?

The pill is one of the most effective methods of preventing pregnancy. If taken correctly, it has a 99% success rate, which means that, statistically, less than one out of every 100 women who take the pill get pregnant each year.

What are the particular benefits of this form of contraceptive?

The pill is proven to be 99% effective at preventing pregnancy, which is one of the highest success rates of any birth control method. If taken correctly, it offers round-the-clock protection with just one daily pill, which most women find to be very convenient. The associated benefits, such as lighter and more regular periods, are also an extra incentive with this form of contraception. Clinical studies have indicated that women who take the pill have a lower risk of developing certain cancers, though research in this area is ongoing.

Are there any side effects or risks?

Like any form of prescription medication, the contraceptive pill does contain a small risk of side effects. If such effects do occur, they are most likely to be very mild and will pass quickly. The more common side effects are headaches, nausea, 'spotting' or breakthrough bleeding and breast tenderness.

Risk factors include smoking, a family history of deep vein thrombosis, obesity, diabetes, high blood pressure and high cholesterol. If any of these apply to you, it is unlikely that you will be prescribed the pill.

Types of combined contraceptive pill

There are three types of combined pill: monophasic, phasic and everyday. The most common is the monophasic pill, which is taken for 21 days, followed by a seven day break. It is called monophasic because every pill contains the same amount of hormones.

The phasic pill is also taken for 21 days with a seven day break, but this type can contain two or three different sections of coloured pills, which correspond with differing amounts of hormones. It is important to take phasic pills in the right order to make sure the different hormones are being released properly, and the pill is at its most effective.

The final type of combined contraceptive pill is the everyday (ED) pill. These packs contain 21 active pills and seven inactive pills, which mean you take one pill every day with no break between packs. These pills also need to be taken in the order they are prescribed to make sure you are fully protected against pregnancy.