Hormone contraceptives are grouped by the type and number of hormones in them. There are two main groups:

• One group contains two types of hormone – oestrogen and progesterone – and these are called combined hormonal contraceptives (CHC) These include the combined pill, contraceptive patch and vaginal rings.
• The other group of hormonal contraception contains just the hormone progesterone (also known as progestogen). Progesterone only tablets are often called the ‘mini pill’ or POP (progesterone only pills). The contraceptive implant, IUS (hormonal coil), and the Depo-Provera injection are also progesterone only long-acting reversible contraception (LARC) methods.

Here we talk about the progesterone only pill.

‘If taken correctly, it can be more than 99% effective. This means that fewer than one woman in 100 who use the progesterone-only pill as contraception will get pregnant in one year” (NHS Choices 2015). However average use of the pill has a 9% failure rate (Centre for Disease Control 2015).

Women said that they liked taking pills because they are easy to use, reliable and are under their control. Progesterone only pills are taken every day continuously. They act mainly by making the mucus covering the cervix thicker which stops sperm reaching an egg. Most need to be taken within 3 hours of the same time every day to work reliably. Newer progesterone-only pills containing desogestrel (such as Cerazette, Desorex, Cerelle and Feanolla) can also prevent an egg from being released by the ovaries (stopping ovulation) most of the time. This pill also needs to be taken every single day without a break, but within 12 hours of the usual time.

This affects the advice given about what to do if a pill is taken late or missed. This advice is detailed in the FPA leaflet ‘the progesterone only pill’.

One of the advantages of progesterone only pills is that they are safe to take for most women, even if there is a medical reason why the combined pill wouldn’t be a safe option for you. This means most women can use them, even if they smoke, have raised blood pressure, are overweight, have diabetes, or suffer from the kind of migraines that rule out the combined pill. They do still interact with some other medications, so it is important to check this if taking tablets for another condition such as epilepsy or HIV (see more on contraception and epilepsy).

Bleeding patterns are not entirely predictable with progesterone only methods of contraception. Bleeding can be light and regular, stop altogether, be more unpredictable or more frequent. If there is lots of bleeding, especially with any other symptoms like pain or discharge, it is important to have a check-up and review with a doctor or nurse. This is to make sure there isn’t another cause for the bleeding, such as an STI. The bleeding pattern does not tell you if your pill is working as contraception or not but you will be covered if you are taking it correctly.

The progesterone only pill can also affect acne (spots) and for some women causes premenstrual type symptoms such as breast tenderness.

The women we spoke to said that taking the pill shows a responsible attitude to contraception and means that sex can be more spontaneous.

Some of the women we talked to stopped taking the pill due to worries over the side effects. Some women didn’t remember to take it every day – in which case they often switched to the contraceptive injection, contraceptive implant or another LARC.

There are pros and cons of taking the pill, and some of the women we spoke to had been put off by friends and family, or had read negative stories in the media. Others didn’t like the idea of taking hormones, although many feel that it’s better to take the pill than risk an unwanted pregnancy.

One said that she understands why clinics have ‘a bit of an agenda’ but feels that women are sometimes under pressure to go on the pill.

Frequently women find that their male partners don’t know much about the pill. Some wish the men would learn more while others explain it to their partners themselves.