Norethisterone Side Effects and How to Avoid Them

Norethisterone is a medication that can delay your period. This can be useful if you are planning on going on holiday or attending a festival or big event and don’t want your period to get in the way.

If you are suitable for norethisterone and are considering taking tablets to delay your period, you may be wondering about the medication’s side effects. This article will cover the potential side effects of norethisterone, how long they last, whether norethisterone is safe, and the side effects of taking norethisterone. We’ll also ask whether the medication causes weight gain.

For a more general guide on norethisterone, visit our page on ‘What Is Norethisterone Used For?’.

Norethisterone Side Effects

Norethisterone has potential side effects, as does any kind of medication. You should be aware of potential side effects before you start taking norethisterone, so make sure you speak to your healthcare provider so that they can give you the best advice.

Let’s take a look at the various side effects of norethisterone, starting with the most common. First, it’s important to remember that not everyone will experience side effects from norethisterone.

When they do occur, the mild side effects of norethisterone may include:

  • Spotting or breakthrough bleeding 
  • Periods stopping
  • Nausea
  • Headache

These mild side effects may affect up to 1 in 10 people. If you are concerned about any of them, speak with your doctor.

Moderate to severe side effects of norethisterone are rarer, and may include:

  • Skin reactions
  • Breast pain
  • Migraine
  • Fluid retention resulting in swelling (oedema)
  • Breathing tenderness
  • Visual disturbances

The frequency of some of these side effects is not known, while others may affect between 1 in 100 and 1 in 1,000 people.

Stop taking norethisterone and seek immediate medical help if you:

  • Get severe headaches
  • Have pain when breathing
  • Have pain when coughing
  • Have a stabbing pain in one leg 
  • Have swelling in one leg
  • Are numb on one side of your body
  • Have sudden chest pain
  • Experience unexplained hearing or vision changes
  • Get jaundice (the yellowing of your skin and whites of your eyes)

You can find a comprehensive list of known norethisterone side effects in the Norethisterone Patient Information Leaflet.

How Long Do Norethisterone Side Effects Last?

You might have different amounts of vaginal bleeding between your normal periods in the first three months of using norethisterone. This is known as spotting (lighter) or breakthrough bleeding (heavier). If this happens you should carry on with your dosing schedule as normal.

Normally, bleeding stops in less than a week. If bleeding carries on for longer, speak with your doctor.

Some common side effects of norethisterone can go away once your body adjusts to the medication. Other side effects may just be temporary, and last for as long as you take norethisterone. If you are concerned about any side effects, ask your doctor for advice.

Norethisterone’s Long-Term Side Effects

Norethisterone is generally considered safe. You can take the medication for months or even years and not encounter any problems.

However, there are potential long-term side effects that some people may experience. If a side effect is caused by a condition or reaction that could continue for months or years, it can be considered long-term.

Using low-dose progestogens such as norethisterone over the long term as part of combined hormone replacement therapy or combined oral contraception has been linked to an increased risk of venous thromboembolism, although it is not certain what part progestogens play in this.

Does Norethisterone Affect Fertility?

There is no evidence to show norethisterone can make you infertile. Even after taking the medication, if you have unprotected sex you can still get pregnant.

Research has highlighted the return of fertility in women after they stopped taking norethisterone, with findings concluding ‘that there is no impairment of fertility in women using norethisterone’.

Does Norethisterone Cause Weight Gain?

There is thought to be a link between norethisterone and weight gain. For this reason, it may cause problems in women who are already overweight.

Research suggests that the weight gain associated with norethisterone ‘may be attributable to hormonally induced water retention’. It was found that there is an average weight gain of 3.6 lbs (1.6 kg) with norethisterone.

Is Norethisterone Safe?

Norethisterone is generally considered safe, provided:

You must speak to your healthcare provider before you start taking norethisterone.

Side Effects Of Stopping Norethisterone

Norethisterone shouldn’t be taken for longer than 20 days to delay your period. You will start three days before your period begins, allowing you to delay your period for up to 17 days. Using norethisterone frequently for long periods is not advised, because long-term use could increase your risk of side effects.

Before you stop taking norethisterone, you should be aware that there are potential side effects of stopping taking the medication. These include menstrual irregularities like bleeding, heavy menstruation and spotting. Your period should arrive within two to three days of stopping norethisterone.

If you want to use norethisterone for longer than 20 days for period delay, ask your doctor for advice.

How To Reduce The Side Effects Of Norethisterone

As we’ve discussed, while not everyone will experience side effects when taking norethisterone, there are several potential side effects that could occur.

We’ll wrap up this article with some tips on how to reduce or prevent the side effects of norethisterone:

  • Take the correct dosage, following the instructions provided with your medication
  • Take the medication on the correct day
  • Ensure your doctor knows about all potential interactions with any medications you are currently taking, as well as any medical conditions you have, before taking the medication
  • Ensure you are a suitable candidate for norethisterone