How do period delay tablets work?

Progestogen hormone, made naturally in the body, sustains the lining of the womb. Decreases in the blood levels triggers shedding of the lining, which causes a period. By taking Provera or norethisterone tablets, hormone levels don't fall and a period won't occur until 2-3 days after you stop taking them. The womb lining is then shed in the same way as in a natural menstrual cycle.

Can I use contraceptive pills to delay my period?

If you are taking a fixed dose combined contraceptive pill (one which contains an oestrogen and a progestogen at the same dose throughout the cycle) you can take packs back-to-back to delay menstrual bleeding. Taking pills continuously stops hormone levels dropping, and so there will be no bleed/period. Simply miss out the pill-free week by taking two packs in a row. This does not apply to 28 day pill packs, where the last 7 days are dummy pills containing no active ingredients. This only works for combined pills not the mini pill. See NHS - How can I delay my period? and extended pill regimes - other ways to take the pill for further advice.

Why do I get monthly periods whilst taking the pill?

The pill (fixed dose combined contraceptive pill) controls the female hormones. One of the effects is stopping the thickening of the lining of the uterus (womb), which would normally occur in preparation for implantation of a fertilised egg. Thus periods are not needed. The (male) doctors who first developed the pill in 1958, decided that women would want monthly bleeds, as it would feel natural. Every three weeks the break between packs or placebo (dummy) pills result in decreasing hormone levels and a withdrawal bleed. As the lining is very thin, this bleeding is light. It is safe to miss the pill free interval and your period as above. Extended-cycle birth control pills, which are taken for 12 weeks with a withdrawal bleed in the 13th, are available in the US, but not in the UK. In the UK the same effect can be achieved by running packs of pills together. The Faculty of Sexual and Reproductive Health in the UK (FSRH) now recommends several routines of extended use of combined pills which reduce the bleed frequency.

My pill is the ED version - do I run packs back-to-back to delay my period?

No. With the ED (Every Day) version of the pill, there are 7 'dummy' pills that do not contain hormone. These are taken at the end of the cycle, in what would be the pill free interval in the standard combined contraceptive pill. These are useful for women who find remembering to take tablets easier if there are no breaks. In order to postpone your period, you need to take hormones continuously, i.e. you must omit the larger 'dummy' pills at the end of a pack and go straight onto the next new pack.

I take a bi-phasic contraceptive pill - can I delay my period?

Yes. These pills vary in strength and ratio of oestrogen to progestogen through the cycle. You can delay your period by continuing to take the last pill type. So, after finishing your pack, you would go straight to the last pills, skipping the pill free week and also first parts of the next pack.

How do I delay my period when taking a mini pill?

Many women will have very infrequent or no periods on the mini pill (progestogen-only pill). If you need to delay a period, discuss with your GP in plenty of time. Swapping to a different type of contraceptive may help or occasionally you may be recommended to use norethisterone or Provera as well. If you are using any hormonal contraception, Dr Fox does not prescribe period delay medication.

Can I delay my period using exercise?

There is evidence that a sudden starting of a high volume of physical training can disrupt the menstrual cycle, but how much is directly due to the exercise and how much to weight loss is not clearly established. Although exercise may be a cause of period delay, it is not a reliable method to achieve this.

Can eating carotene containing foods affect the menstrual cycle?

It is said that eating beta-carotene, in orange foods such as papaya, carrots, pumpkins, and pomegranate, raises the level of oestrogen causing an early period. Bringing a period forward can avoid having a bleed at a particular time. There is evidence that beta-carotene varies with the menstrual cycle, and that there is a link between beta-carotene and oestrogen levels. However the exact mechanisms remain unclear and eating the above foods is not proved to have the desired effect.

Can stress delay periods?

Yes, a natural response to severe stress is not to ovulate (hence not falling pregnant at a bad time) but it is neither easy nor desirable to use stress in this way.

Does eating spicy food bring forward a period?

This is an often quoted home remedy for triggering an early period. There is no published data to support (or disprove) this. Either way, avoiding spicy foods is unlikely to be a reliable method to delay a period.

Can I use herbs to alter my period?

Herbalists, past and present, use shepherd's purse and yarrow to reduce length and heavy bleeding at menstruation. There is research evidence to support the effectiveness of each to decrease menstrual bleeding but they don't alter timing.

Does taking Vitamin B6 supplements delay menstrual bleeding?

Medical trials involving Vitamin B6 looked at its role in the treatment of pre-menstrual syndrome (PMS). The low quality of most of the trials means that the conclusions may not be valid, but they show that doses of 50-100mg/day can help with PMS symptoms. There is no medical evidence that Vitamin B6 will reliably delay a period, though it is often discussed in online forums.

Can eating gelatin delay menstruation?

It is said that gelatin has anti-estrogenic properties, which causes period delay. There is no scientific research to either back this up or disprove it. It cannot be recommended as a way to delay periods, only direct hormonal treatments reliably do this. There is also no research to show that gram lentils or apple cider vinegar (other foods recommended for period delay) work either.

Does drinking coffee delay periods?

No. Coffee has been shown to affect female hormone levels but the effects are not significant enough or consistent enough to be used to delay a period.

Can heating the pelvis bring a period on earlier?

Warming the uterus for example by sitting in a hot bath or using a warm compress on the lower abdomen, can cause local dilation of blood vessels and increased blood supply, which increases the menstrual blood flow. It is unlikely to trigger a period that wasn't about to start anyway.

Does taking hormones to delay periods cause blood clots?

Anything that increases the levels of female hormones, especially oestrogen, can cause an increase in the risk of developing blood clots. This includes pregnancy, taking hormonal contraception, as well as using hormones to delay the period.

The risk of blood clots when using hormones to delay periods is very small as they are used for a very short time compared to contraceptive use, although in stronger doses. The risk is greater with norethisterone as this is changed from a progestogen into an oestrogen in the body. Provera is the least risky option.

I can't take the contraceptive pill - can I take Provera or norethisterone to delay my period?

You can possibly take Provera but Dr Fox recommends that you discuss this with your own GP. It will depend on the reason for not being able to take the pill. Provera and norethisterone are progestogens similar to the hormones in the mini pill but taken in higher doses, to delay periods. Norethisterone is converted to oestrogen in the body, so if you can't take the combined pill, you shouldn't use norethisterone.

Will Provera or norethisterone stop me getting pregnant as well as delaying my period?

Unfortunately not! Although the hormones are similar to those in the mini pill, implants, and injections, they are not taken for long enough to have a contraceptive effect. Other contraceptives, e.g. barrier methods, should be used as well whilst delaying a period with Provera or norethisterone.

How long can I delay my period for?

Dr Fox supplies 30 or 60 tablets to delay periods by 7 days or 17 days. Take one tablet 3 times a day, from 3 days before the period is expected. If taken closer to the period they may not work as natural hormone levels will have already started to drop. They can be taken for as long as required, with the period starting around 2-3 days after stopping the tablets.

If you want to delay your period for longer than 17 days, consult your own GP.

How often can I delay my period?

Taking tablets to delay periods is for occasional use only. Dr Fox will prescribe a maximum of 4 times per year. If you need more control over the timing of periods, discuss with your own GP. Several methods of contraception also have the effect of stopping or significantly reducing periods, and may suit your needs better.

Do period delay tablets have side effects?

As with all medications some people may experience side effects.

Provera is taken at much higher doses for other medical conditions and most women using it for period delay have no problems. The common reported side effects include headache and feeling sick.

Many women have no problems when taking norethisterone to delay their period. The reported side effects include bloating and fluid retention which may worsen pre-existing migraine, high blood pressure, epilepsy, or asthma. Other effects can be breast tenderness, loss of libido, and very rarely jaundice (yellowing of the skin due to liver disease).

In about 1 in 10 women there is mild spotting or breakthrough bleeding as the cycle is lengthened with both Provera or norethisterone.

Is delaying a period safe?

It is safe to delay your period if you have no risk factors to taking the hormone medication. There is no medical reason why a woman must have a regular monthly bleed. Many contraceptives are now used in a way to only have 3 or 4 periods per year.

Which is better - norethisterone or Provera?

Norethisterone 5mg three times a day has been used by women for many years to delay periods. It has recently been shown that there is a slightly higher risk of developing blood clots due to it being changed into ethinyl oestradiol in the body, which makes it into a similar medication to the combined contraceptive pill. For this reason many doctors prefer to prescribe Provera 10mg three times a day, as this remains as a progestogen in the body, and so has less risk of blood clots.

There is no medical research as to which is most effective but some women find that there is more chance of breakthrough bleeding with Provera.

Norethisterone is provided under the manufacturers licence for period delay, but using Provera in this way is 'off-label' which means that the doctors take responsibility for the prescribing.

I take other medications - can I take tablets to delay my period?

There are some interactions with other medications, which may make norethisterone or Provera less effective or alter the effectiveness of the other medication.

If you are taking any of those listed below, Dr Fox is unable to prescribe for you, please consult your own GP.

  • Medicines to treat epilepsy (e.g. phenytoin, carbamazepine).
  • Antiviral medicines to treat HIV (e.g. ritonavir, nelfinavir, nevirapine, efavirenz).
  • Blood thinning medication (e.g. warfarin).
  • Herbal preparations containing¬†St¬†John's Wort (Hypericum perforatum).
  • Antibiotics for tuberculosis (e.g. rifampicin, rifabutin).
  • Other antibiotic medicines (e.g. doxycycline, lymecycline, other tetracyclines, co-trimoxazole).
  • Anticancer medicines.
  • Ciclosporin (for suppressing the immune system).
  • Non-steroidal inflammatory drugs (NSAIDs) for treating pain and inflammation.
  • Medicines for high blood pressure.

I use hormonal contraception - can I use Provera or norethisterone to delay my period?

Many of these contraceptive methods (e.g. combined pill, mini pill, contraceptive patch, contraceptive vaginal ring, implant, hormone coil, depot injection) either reduce the frequency of periods or stop them completely. Some can be used to delay a period. Please discuss with your own GP.

Dr Fox cannot prescribe if you already take other hormones.

Do period delay tablets contain allergens?

Always read the patient information leaflet supplied with medicine packs for a full list of ingredients.

  • Provera 10mg tablets contain both lactose and sucrose and may be unsuitable for women who are unable to take these sugars.
  • Provera 10mg tablets as supplied by Dr Fox for period delay do not contain dye. However, Provera 2.5mg tablets contain sunset yellow (E110) and some people can be allergic to this.
  • Norethisterone tablets are made by several different manufacturers. All brands currently available in the UK contain lactose but not sucrose.

I have a short monthly cycle - when should I start taking period delay tablets?

If you have a shorter monthly cycle (e.g. 24 days and not a standard 28 day cycle), you should start taking norethisterone or Provera 3 days before your own next expected period, so in this case 21 days after the start of your last period. Likewise, if you generally have a longer cycle, start the tablets 3 days before you would expect your next period.

Period delay tablets
Dr Tony Steele

Authored 14 July 2014 by Dr Tony Steele
MB ChB Sheffield University 1983. Former hospital doctor and GP. GMC no. 2825328

Reviewed by Dr A. Wood, Dr C. Pugh, Dr B. Babor
Last reviewed 04 August 2021
Last updated 17 May 2024