Norethisterone is a medication that can be used to delay your period for up to 17 days. It works by keeping your progesterone levels topped up, which prevents the lining of the womb from breaking down and stops periods from occurring. To delay your period, you should take norethisterone three days before your expected period date, and then take one tablet three times a day for as long as you want to delay your period, for a maximum of 20 days. Once you stop taking norethisterone, your period should start within two to three days.

If you take norethisterone on the first day of your period, it is unlikely to have any effect on your current period. However, it may make your next period lighter or less intense. It is important to note that norethisterone is not suitable for everyone. You cannot take it if you have liver problems, certain heart conditions, or if you have a personal or family history of blood clots. It cannot be taken alongside the contraceptive pill and other medications, such as some antivirals and antiepileptics. If you are unsure whether norethisterone is suitable for you, you should consult your doctor.