What to do if you missed your period

Reviewed by Dr Neel Patel

A late or missed period can be concerning. But it’s usually nothing to worry about. Your menstrual cycle is often influenced by factors such as stress and changing exercise habits. However, if you’ve had unprotected sex, it could also be a sign of pregnancy.

Read on to find out more about what to do if your period is late, or you miss one completely, as well as common causes and how to avoid getting pregnant if you’re not family planning. 

How do you know if your period is late?

Most periods occur approximately every 28 days, however some women have a slightly longer or shorter cycle that can be anywhere from 21 to 40 days. It’s also common to have an irregular menstrual cycle, which means your period might appear at different times during the month. 

There are a number of things that can happen to your body on and around your period and can help you to know when it’ll start. Period pain is the most common symptom of menstruation and can happen in the day or two before you bleed. PMS is also extremely normal and can cause various symptoms such as anxiety, bloating, headaches and tiredness.

If your period usually follows the same cycle (such as every 28 days) then it is considered late if it doesn’t occur after one day. However it is not an immediate cause for concern. Keep reading to discover several things that can delay your period.

Is it normal to miss a period? 

Missing a period can be confusing but it’s actually very common and doesn’t necessarily mean you are pregnant. Various factors can affect your menstrual cycle such as stress, weight changes and the contraceptive method that you use. 

How long after a missed period should you worry?  

If your periods are usually regular, you may wish to take a pregnancy test after the first day that it is late. Those with irregular cycles can wait up to 40 days after their last period.

Causes of a missed period

There are a few different reasons why you may have missed your period. Here are the most common:

Stress

Stress impacts the body in many ways, one of which is the menstrual cycle. If you’re stressed, your periods may become heavier, more painful, longer or shorter. Or they may stop altogether. 

Avoiding stress by practising self-care or having talking therapies such as CBT can help you to manage these symptoms.

Weight

You may find that your periods stop if you suddenly lose weight. This is because restricting calories can stop the production of hormones that are needed for ovulation. 

Alternatively, being overweight can also impact your menstrual cycle, causing the body to overproduce oestrogen which affects how often periods occur.

If you are over or underweight, your GP may refer you to a dietitian who will help you to reach a healthy weight.

Exercise

Too much exercise can place stress on the body which in turn, can affect the hormones responsible for your periods. If your periods become irregular, or stop completely, you may wish to reduce your level of physical activity. Athletes should speak to a specialist doctor who can advise on how to manage exercise and their periods.

The contraceptive pill 

Some methods of contraception, such as the coil and injection, can result in a missed period. This is normal and not usually something to be worried about. The contraceptive pill can also make periods irregular and be used to delay your period if you wish to skip a cycle.

Taking packets of the pill back-to-back is perfectly safe and useful for when you want to avoid a bleed such as on your holiday.

Period delay medication (Norethisterone) will also delay your period by up to 17 days and can be taken if you’re not already on the combined pill.

Menopause 

Menopause occurs between the ages of 45 and 55. During this time, your periods will become irregular and eventually stop as a result of hormone levels lowering. This can also happen earlier, otherwise known as perimenopause. 

PCOS 

As many as 1 in 3 people with PCOS (polycystic ovary syndrome) experience stopped periods as a result of the condition. This is due to underdeveloped sacs in which the eggs normally grow, causing the body not to ovulate and instead, skip a period.

Pregnancy

If you are sexually active and you’ve missed a period, there is a chance you might be pregnant. This can happen even if you have used contraception. Your period might be delayed, so it’s worth waiting a few days before doing a pregnancy test. It is also possible to get pregnant whilst on your period if ovulation has been delayed.

When to take a pregnancy test after a missed period? 

For the most reliable results, take a pregnancy test any time after the first day of your missed period to determine whether or not you are pregnant. You can do this at any time of day. If the test is negative and you think you may be pregnant, wait a few days and take another test.

Should you take a pregnancy test after unprotected sex? 

You should take a pregnancy test at least 21 days after you last had unprotected sex, or if your method of contraception failed (e.g. the condom split or you forgot to take your pill). 

You should also take an STI test after having unprotected sex, even if you don’t have any symptoms. This will help to protect you against infections such as chlamydia and gonorrhoea that if left untreated can cause serious complications.

Should you take a pregnancy test after emergency contraception? 

If you have taken emergency contraception (either by taking the morning after pill or having a coil put in place), you may wish to take a pregnancy test to check it has been effective. 

Remember that emergency contraception does not protect you from STIs. You should take an STI test if you have had unprotected sex.

What to do if you miss your period but get a negative result? 

If you have taken a pregnancy test and had a negative result, then it might be worth visiting your GP to discuss other possible causes for a missed period. One missed period is normally nothing to worry about, but if your period becomes unpredictable, or you miss three periods in a row, you should seek medical advice. Your health care professional will be able to test for causes such as PCOS or discuss any emotional issues you are having.

What to do if you think you might be pregnant?

A pregnancy scare can be a stressful, upsetting experience. Waiting for the results of a test is scary, but remember that there are plenty of resources to help you, no matter the results.

It can be helpful to know the early signs of pregnancy. Aside from a missed period, these include:

• Tender breasts
• Nausea and vomiting
• Tiredness
• Constipation
• Urinating more often
• Changes to sense of smell and taste

Having one of these symptoms doesn’t necessarily mean you are pregnant, it could be a result of stress, or a late period.

Don’t be afraid to get support during this scary time. Your friends, family and partner can offer advice and be someone to voice your worries to. You can also speak to your GP if you have any concerns.

Not trying to conceive? How to protect yourself from pregnancy

Using contraception is the only way to protect yourself against unplanned pregnancy. There are many different methods of birth control, each suitable for different ages that can be used alone or combined for extra protection.

Routine contraception 

There are two different types of contraception, hormonal and non-hormonal. The most common form of hormonal contraception is the combined pill, which prevents you from releasing an egg and getting pregnant. The patch and vaginal ring contain the same hormones but come in two different forms. The contraceptive patch is worn on your skin and changed once a week, whilst the vaginal ring is inserted into the vagina and changed every three weeks. Alternatively is the mini pill, which only contains progestogen and doesn’t come with a pill-free week. When used properly, these methods are effective for 99% of women.

Once you stop taking the pill, your body will begin to ovulate. It’s therefore important to remember to take it everyday and use an alternative method of contraception once you come off the pill to avoid getting pregnant.

Condoms are also a popular method of contraception that act as a barrier, preventing sperm from entering the womb and fertilising an egg. They also offer protection against STIs and can be used in addition to hormonal contraceptive methods.

Emergency contraception 

If you have had unprotected sex, you can take emergency contraception to limit the chances of unplanned pregnancy. There are two options available - the emergency contraceptive pill and an intrauterine device (IUD or coil).

The emergency contraceptive pill (morning after pill) needs to be taken within three days (Levonorgestrel) or five days (ellaOne) of unprotected sex. The sooner it is taken, the more effective it will be. An IUD, or coil, can be fitted up to five days after unprotected sex and is more effective than the morning after pill.

In summary, a late or missed period is very normal and can be caused by a number of reasons. Weight changes, stress and PCOS often impact your menstrual cycle and can delay or skip a period. However if you have had unprotected sex or you think your contraception has failed, it’s a good idea to take a pregnancy test at least one day after your missed period.

If your periods become irregular, or you miss three periods in a row, you should speak to your GP to find out if there are any other underlying causes.

Get more advice from LloydsPharmacy Online Doctor to help you understand pregnancy and periods. 

References

https://www.nhs.uk/conditions/stopped-or-missed-periods/ 
https://www.nhs.uk/pregnancy/trying-for-a-baby/doing-a-pregnancy-test/
https://www.nhs.uk/conditions/contraception/emergency-contraception/?tabname=which-is-best-for-me