In short

  • Norethisterone is a non-contraceptive, period delay drug.
  • It works by regulating the level of progesterone in your blood.
  • During your menstrual cycle, a decrease in your natural progestogen causes your period to begin.

Norethisterone is a non-contraceptive, period delay drug. It works by regulating the level of progesterone in your blood. During your menstrual cycle, a decrease in your natural progestogen causes your period to begin. Norethisterone increases your body’s level of progesterone, temporarily preventing a period from occurring. It does not affect the egg, or the sperm fertilising the egg. Therefore, Norethisterone does not affect conception and is not a suitable contraceptive form, but some contraceptive pills can be used to period delay. Speak to your doctor to explore your options.

Does Norethisterone protect from STDs?

Norethisterone’s only purpose is to alter your body’s level of progesterone and delay your period. Norethisterone does not have any protective effects against HIV or other STIs. While taking Norethisterone, it is essential to still practice safe sex to avoid pregnancy or STIs.

Which contraceptive pills can be used for period delay?

If you have already been taking the pill for several weeks, combined contraceptive pills, e.g. Cilest, Microgynon, Rigevidon and Yasmin, can also be used for period delay. (You should not start taking the contraceptive pill shortly before your period is due to delay a period.) For those pills mentioned above, you can take two packets of pills back to back, to alter your hormone levels and prevent a period. It is possible to take three packs back to back, but many women do not find this an effective method of period delay and experience spotting. It may be possible to use other pills for period delay, but you should speak to your pharmacist who can tell you which pills to miss out for period delay.

Which contraceptive pills cannot be used for period delay?

Phasic pills contain different levels of hormones in each pill, and most are not suitable for period delay. Phasic contraceptive pills include Aranelle, jenest, mircette, nelova, necon.

The Mini Pill, e.g. Cerazette, involves taking a pill every day; therefore it cannot be used for period delay.

View our complete range of period delay tablets

View our complete range of contraceptive pills

Sources

References

2 sources were selected to match the subject of this article. Link destinations were checked twice when added. This does not mean every statement has been individually source-mapped or clinically approved.

  1. Choosing a medicine to delay periods

    NHS Specialist Pharmacy Service · HTML · NHS professional medicines guidance · Link destination checked 5 September 2026

  2. How well contraception works at preventing pregnancy

    NHS · HTML · NHS contraception guidance · Link destination checked 5 September 2026

Reference links open the cited source pages. If you spot something out of date, tell our content team.

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Authored by

Hywel McGlinchy - Pharmacist and Medical Writer

Pharmacist / Content Writer

Hywel has been a registered pharmacist since 2017; he started with Simple Online Pharmacy in 2020. Hywel was responsible for helping review and author accurate site content. He worked with our GPs to make sure all aspects of the medications mentioned are covered.

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Medically reviewed by

Karim Nassar, Co-Founder, Pharmacist & Author

Karim Nassar

Co-Founder, Pharmacist & Author

Karim is a registered pharmacist with the General Pharmaceutical Council (GPhC) and was a founding member of Simple Online Healthcare in 2015. With a Master of Pharmacy degree from Strathclyde University, Karim brings a strong foundation in pharmaceutical care and a passion for leveraging digital solutions to improve patient access to healthcare.

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