Period delay

Medical information

Written and reviewed by a team of doctors. Dr Fox is regulated by the CQC & GPhC.

How period delay tablets works

Medroxyprogesterone 10mg (Provera) and norethisterone 5mg tablets can be taken three times daily to delay periods. Start tablets at least 3 days before the expected start of the period and continue for as long as needed. A period bleed will normally start 2-3 days, and possibly longer, after stopping the tablets.

The balance of hormones changes during the menstrual cycle. During the time medroxyprogesterone or norethisterone tablets are being taken a period (shedding of the womb lining) will be delayed.

Women currently taking a contraceptive pill should not use norethisterone to delay their periods. There is more information about delaying periods when taking contraceptive pills on the NHS page How can I delay my period?

Medroxyprogesterone and norethisterone are not contraceptives and will not prevent pregnancy.

Length of treatment

Dr Fox can supply sufficient medroxyprogesterone or norethisterone tablets to delay a period for up to 17 days, a maximum of 60 tablets. If period delay of less than 17 days is required, the tablets are taken for fewer days and fewer tablets are required.

Taking tablets to delay periods is for occasional use only and should not be requested more than once in 3 months (four times per year). If period delay is needed more frequently or for longer, consult your own GP. Often using a form of hormonal contraceptive can be an effective period control, with many contraceptives reducing or stopping periods completely.

Patients MUST read manufacturer's patient information leaflets (links below) supplied with tablets.

Other medications - interactions

There are a few medications which can interact with Provera or norethisterone. This may make either medication less effective. Checks are carried out in the online consultation.

Possible side effects

As with all medications, medroxyprogesterone and norethisterone can cause side effects, although these are usually not troublesome. Further information about side effects can be found in manufacturer's patient information leaflets supplied in medicine packs.

Fluid retention

Medroxyprogesterone and norethisterone are progestogens which can cause fluid retention. This can make certain pre-existing conditions worse. You may still be able to use period delay medication but extra care should be taken and Dr Fox cannot prescribe period delay medication for you, if you suffer from:

• Epilepsy.
• Migraine.
• Asthma.
• Heart disease.
• Kidney disease.

Please discuss period delay with your regular doctor if the above applies.

Medroxyprogesterone 10mg side effects

Medroxyprogesterone side-effects are usually not troublesome at the doses used for period delay. They most commonly include headache, nausea or feeling sick, and unexpected or unusual vaginal bleeding or spotting.

Norethisterone 5mg side effects

The most commonly reported side effects are bloating, breast tenderness, and loss of libido. Side effects are more likely if norethisterone is taken long term, rather than in a short course to delay periods.

Some women taking norethisterone experience fluid retention which can worsen pre-existing migraine, epilepsy, blood pressure, and asthma.

Very rare sensitivity reactions

Very rarely, medroxyprogesterone and norethisterone may cause a severe allergic reaction. Sudden onset of some or all of the following require emergency treatment (telephone 999 in the UK):

• Wheezing.
• Difficulty breathing.
• Feeling faint.
• Swelling of the face or tongue.
• Swelling of the hands and feet.
• Intense itchy skin rash.

Reasons to stop period delay medication immediately

• New migraine type headache.
• Significant increase in blood pressure.
• Jaundice or liver function deterioration.

Period delay medication is not recommended

Medroxyprogesterone and norethisterone are not recommended for period delay, if you have or have had in the past:

• Angina (heart pain).
• Heart attack.
• High blood pressure.
• Liver disease.
• Jaundice in pregnancy.
• Severe itching or a severe blistering rash in pregnancy (rare).
• Porphyria (rare metabolic disorder).
• Genital or breast cancer or liver tumours.
• Systemic lupus erythematosus (SLE).
• Diabetes.
• Depression.
• Otosclerosis (rare cause of hearing problems).

Risk of blood clots (Venous Thromboembolism)

All women have a small chance of having a blood clot in the veins of the legs or in the lungs or other parts of the body. The risk of a clot is very slightly increased if norethisterone is being taken. There is much less increased risk when taking medroxyprogesterone.

Dr Fox cannot prescribe medroxyprogesterone or norethisterone if the following apply, as they also increase the risk of blood clots:

• Very overweight.
• Previous blood clot in the veins or lungs.
• Relatives have had blood clots.
• Immobility for long periods of time, e.g. after an operation, or during a long haul flight (6+ hours).
• After serious injury or major surgery.
• History of repeated miscarriage.

In about 10% of women there may be light spotting or bleeding the longer the cycle is extended.

Dr Fox supplies period delay tablets on prescription – you are required to answer a short medical questionnaire before your order can be completed.

Authored 17 November 2012 by Dr Tony Steele
MB ChB Sheffield University 1983. Former hospital doctor and GP. GMC no. 2825328

Reviewed by Dr C. Pugh, Dr B. Babor
Last reviewed 30 May 2025
Last updated 18 September 2026
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