Norethisterone is a prescription-only medication, so you’ll need a consultation with a doctor or pharmacist before you can get it. In the UK, this can be done through your GP, a high street pharmacy offering period delay services, or a regulated online pharmacy. In the US, the same drug is available under the name norethindrone and also requires a prescription.
Getting Norethisterone Through Your GP
The most straightforward route is booking an appointment with your GP. You’ll explain why you need the medication (most commonly to delay a period for a holiday, event, or personal reasons), and your doctor will review your medical history before writing a prescription. GP appointments are free on the NHS, though you’ll pay the standard prescription charge for the medication itself unless you’re exempt.
The key limitation here is timing. GP appointments can take days or weeks to arrange, and you ideally need to start taking norethisterone three days before your period is due. If your event is soon, a GP visit may not be fast enough.
Pharmacy and Online Consultation Services
Many UK pharmacies now offer period delay consultations directly, without needing a GP referral. You speak with a pharmacist, answer screening questions about your health, and receive the medication on the spot if appropriate. This is often the quickest in-person option.
Regulated online pharmacies follow a similar process digitally. You complete a medical questionnaire covering your health history, current medications, and any risk factors. A registered doctor reviews your answers and, if everything checks out, approves a prescription. The medication is then delivered, typically the next day. Look for services registered with the General Pharmaceutical Council (GPhC) or the Care Quality Commission (CQC) to ensure legitimacy.
Whether online or in person, expect to be asked about your history of blood clots, liver problems, unexplained vaginal bleeding, and whether you could be pregnant. These aren’t formalities. They determine whether the medication is safe for you specifically.
How Norethisterone Works
Norethisterone is a synthetic version of progesterone, the hormone that maintains the lining of your womb during the second half of your menstrual cycle. Normally, progesterone levels drop just before your period, triggering the lining to shed. Taking norethisterone keeps progesterone levels artificially high, preventing that shedding for as long as you continue taking it.
The standard approach for period delay is 5 mg taken three times a day, starting three days before your period is expected. You continue taking it for as long as you want to delay your period, up to around 17 days in most cases. Your period will typically arrive two to three days after you stop.
Who Shouldn’t Take It
Norethisterone isn’t suitable for everyone. You won’t be prescribed it if you:
- Are pregnant or think you might be
- Have a personal or family history of blood clots, including deep vein thrombosis
- Have a history of heart attack or angina
- Have liver problems
- Have unexplained vaginal bleeding that hasn’t been investigated
- Have a rare blood condition called porphyria
If you have epilepsy, migraines, asthma, or kidney problems, you may still be able to take it, but your doctor will want to weigh the risks more carefully. Being very overweight, having lupus, or being immobile for long periods (such as after surgery or on a long flight) all increase the risk of blood clots while taking norethisterone.
Common Side Effects
The most frequently reported side effects are breast tenderness, weight gain, acne, and increased facial hair growth. Some people also experience mood changes, headaches, or nausea. Irregular bleeding or spotting can happen, which somewhat defeats the purpose if you’re taking it to avoid a period during a specific event.
More serious side effects are rare but include signs of a blood clot: pain, redness, or swelling in a leg, chest tightness, or sudden changes in vision. These need immediate medical attention.
Alternatives for Delaying Your Period
If norethisterone isn’t suitable for you, or you’d prefer a different approach, several alternatives exist.
If you’re already on a combined oral contraceptive pill, you can delay your withdrawal bleed by running two or more packs back to back without the usual break. This works best with monophasic pills (where every active pill contains the same dose). Breakthrough bleeding becomes more likely the longer you extend the cycle, but your bleed will typically start about three days after you stop taking the pills.
The vaginal ring works similarly. Inserting a new ring every four weeks without a break suppresses bleeding. After six months of extended use, roughly 89% of users report no bleeding or only minimal spotting.
Contraceptive patches can also be used in an extended cycle and are equally effective at delaying a withdrawal bleed as continuous pill use, though skin irritation at the patch site is a common drawback.
Medroxyprogesterone is another progestogen option, available as tablets or an injection. The injectable form takes time to become effective: only about 30% of users have no periods during the first three months, rising to 55% after a year. The tablet form can reduce heavy bleeding, though breakthrough spotting still occurs. Periods usually resume within three days of stopping the tablets. One advantage of the injectable form is that a history of blood clots is not a contraindication, unlike norethisterone.
Planning Ahead
Timing matters more than most people realize. You need to start norethisterone three days before your expected period, which means you need your prescription in hand before that. If your cycle is irregular, predicting the right start date becomes harder, and your doctor may suggest a different strategy altogether.
If you’re planning around a specific event, give yourself at least two weeks of lead time to arrange a consultation, get the prescription filled, and have a buffer in case your cycle shifts. Waiting until the last minute narrows your options considerably, especially if your GP has limited availability.