Noriday tablets are a type of hormonal contraceptive commonly known as the 'mini pill' or progestogen-only pill (POP). They contain the active ingredient norethisterone, which is a synthetic progestogen, similar to the natural progestogens produced by the body.
Noriday tablets prevent pregnancy in three ways.
Firstly, they affect the natural mucus at the neck of the womb (cervix). Norethisterone increases the thickness of this mucus, making it more difficult for sperm to cross from the vagina into the womb. By preventing sperm entering the womb, successful fertilisation of an egg, leading to pregnancy, is less likely.
Norethisterone also changes the quality of the womb lining (endometrium). The changes prevent any eggs that have been fertilised from successfully implanting onto the wall of the womb.
Lastly, norethisterone may prevent the release of an egg from the ovaries, however, this may not occur in all women who take the mini-pill.