Norethisterone: What It Is and Why It's Safe

Getting your period when you’re due to go on holiday is inconvenient and often frustrating. With the right treatment, however, you can safely delay it and stop it interfering with your plans. We explain how below.

Updated: Thursday 15 April 2021

Picture this. The holiday you booked six months ago with your friends is just around the corner. You’ve got everything: your clothes are packed, your shades are bought and you’ve chosen your reading material for the plane. You’ve looked forward to nothing else for weeks, and in just a few days you’ll be jetting off to sunny skies and blue shores.

But then, some familiar feelings begin to emerge. Your mood changes, the cramps start, and you realise that time of the month has rolled around again. You’ve got time to get necessities from the shop before you head out, but you already know things aren’t going to be as great by the time you reach the airport.

The reality is that your period doesn’t always have the best timing - and nothing stops the excitement of a holiday than unexpectedly being on your time of the month. The good news, however, is that you don’t have to leave it to chance. With the right treatment, you can safely delay your period and enjoy your trip without worrying about it.

Sounds great - so how can I delay my period?

The safest way to temporarily delay your period is with the use of a prescription treatment known as norethisterone. Noresthisterone is a synthetic version of the female sex hormone progesterone, which fluctuates naturally in accordance with the monthly menstrual cycle. Since it was first synthesised in 1951, norethisterone has been used on women for a number of purposes, including as part of contraceptive pills, as a treatment for endometriosis and even to help manage breast cancer. In addition, norethisterone has another useful effect: the ability to delay periods.

How does norethisterone work, then?

Progesterone is one of the hormones that determine what part of your menstrual cycle you’re on at any one time. At its peak, progesterone will cause your womb lining to flourish and prepare it to receive a fertilized egg. If you don’t get pregnant at that time, your progesterone levels will fall again, which causes the womb lining to shed and your period to begin.

As a synthetic version of progesterone, norethisterone allows you to delay your period by essentially tricking your body into thinking it’s pregnant. When you take norethisterone, you keep the levels of progesterone in your body at the level it would be if you had conceived at the time of ovulation. As a result, your body keeps the womb lining in the same state, preventing you from having a period until you stop taking the medication.

When taken as a period delay medication, norethisterone can allow you to delay your period for up to 17 days - meaning you’ll be able to enjoy your trip abroad without worrying about starting your time of the month.

Won’t that mess with your hormones, though?

Functionally, yes. But so do many other medications. As long as you use norethisterone on a temporary basis, it’s very safe for the majority of women who use it. In fact, studies investigating the impact of norethisterone at doses of 60mg a day for extended treatment durations found no adverse effects. Norethisterone is prescribed for period delay in strengths of 5mg, meaning you won’t reach anywhere near those levels while taking it.

That said, it’s important to remember that norethisterone prescribed as a period delay treatment should still only be used on a temporary and occasional basis. If you’re concerned about your periods and want to know your options for delaying them for longer durations, you should contact your GP for advice.

Are there any side effects?

Some women might experience side effects when taking norethisterone, but the good news is that they’re mild in most cases. If you do experience side effects when taking norethisterone, you might experience breast tenderness, nausea, headaches or disturbances in your mood and sex drive. If any of these side effects concern you, you should call your GP or a pharmacist for further advice.

Are there any reasons why someone shouldn’t take norethisterone?

Like any other medication, there are some instances in which it might not be suitable to take norethisterone. Women who are pregnant, for example, obviously wouldn’t need to delay their period with norethisterone. Women who are breastfeeding, also, shouldn’t take norethisterone.

Another instance where women shouldn’t take norethisterone is if they or their family members have a history of blood clots in the legs (for example a deep vein thrombosis) or the lungs (such as a pulmonary embolism). Again, if these circumstances apply to you and you’re thinking of delaying your period you should speak to your GP about the options available to you.

Other circumstances in which women should not take norethisterone include:

• If you have abnormal vaginal bleeding you have not seen a doctor about
• If you have a history of genital or breast cancer (this does not apply to women who have been prescribed norethisterone to manage breast cancer)
• If you have had angina, a heart attack or stroke caused by a blood clot
• If you have had jaundice, severe itching or pemphigoid gestationis while pregnant
• If you have porphyria

Ok - and how do I take the medication?

Norethisterone prescribed for period delay is taken in 5mg doses, three times a day, for a maximum of 14 days. You should start taking the medication three days before your period is due, and once you stop taking the medication your period should start two to three days later.

The bottom line

Getting your period when you’re due to go on holiday is inconvenient and often frustrating. But norethisterone can allow you to effectively delay your period for up to 17 days - allowing you to enjoy your time abroad care-free. And if you’re worried about its safety, don’t be - norethisterone is safe for most women who use it on an occasional and temporary basis.