The contraceptive pill most commonly prescribed to younger women in the UK and often referred to simply as ‘the pill' is actually only one of the types of birth control pill available in Britain. Another contraception option is the progesterone only pill (POP) which is often called the ‘minipill'. The minipill is different to the combined contraceptive pill because the POP contains only one of the female sex hormones - namely progesterone. The combined contraceptive pill contains both oestrogen and progesterone. The POP is therefore recommended for women who do not want put excess oestrogen into their bodies, or for women for whom it would be dangerous to take an oestrogen-based birth control pill.
How The POP Works
Different brands of the progesterone only pill work in different ways. Generally, these pills stop you getting pregnant by thickening your cervical mucus - making it more difficult for your partner's sperm cells to reach the area where they could possibly fertilise an egg; or by thinning the lining of your uterus, which stops a fertilised egg from implanting there and growing into a baby; or by preventing ovulation, thus leaving you with no possibility of getting pregnant.
How Is The POP Taken?
One of the perceived advantages of the POP is that you take it every day - no need to remember when to start taking your pills again after your seven-day break. The POP comes in packets of 28 pills. Different types of POP are available. The three-hour pill must be taken within three hours of the same time every day in order to be effective. The 12 -hour pill must be taken within 12 hours of the same time every day. Some women feel restricted by these time limits - they prefer the 24-hour window offered by the combined contraceptive pill.
If the progesterone only pill is taken correctly, it is between 96 and 99 % effective. Among typical users, who sometimes forget to take the pill on time, the effectiveness rate is 92 %. These rates are based on studies of women who took the POP for one year and the number of these women who became pregnant during that year.