Late Period

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Why is my period late?

Though pregnancy may be the first thing that comes to mind if your period is late, but this can happen for many reasons.  

Your period may sometimes be late, or late, for no apparent reason, but may also be caused by lifestyle factors, hormonal imbalances, or underlying illness

The average menstrual cycle (the time between your periods) is around 28 days, but normal cycles can vary in length from 21 to 40 days. Each woman will have their own cycle length, and that can be perfectly healthy.

Many women have irregular periods, meaning their cycle may change from one month to the next, which may also be normal for some women. Irregular periods are especially common when you first start having periods (menarche) and when your periods begin to stop (perimenopause). 

Even if your cycle is normally regular, there are many reasons why your period may be late, you may skip a period, or your periods may stop altogether. 

What causes missed or late periods?

Some common causes of late or missed periods include: 


If you are sexually active and your period is late, the first thing to rule out is pregnancy. Your result may be more accurate if you wait a week following your missed expected period date before taking a test. Tests vary, so discuss any pregnancy test with a pharmacist before buying and using it. Remember most contraception works less than 99% of the time, so pregnancy can occur even if you are using contraception. If in doubt, take a test. 


Prolonged stress affects the hormones that regulate your menstrual cycle and can cause late or even missed periods. Many women also report an increase in period pain when they are stressed. Try to reduce your stress levels by making lifestyle changes like eating healthily, taking regular exercise, and reducing your alcohol and caffeine intake, and using online resources for stress management, like the Mind website. If your stress is affecting your physical or mental health, seek help from a GP. 


Taking excessive amounts of exercise can affect your hormones and stop your periods. If you regularly exercise to extreme levels, for example, if you are an athlete or marathon runner, this can affect your periods and you may wish to seek help from a GP.


Hormonal birth control such as the contraceptive pill can cause you to miss a period, especially when you first start or stop taking it. 

Some types of contraception such as the progestogen-only pill (mini pill), the Mirena intrauterine device (IUD) and contraceptive injection may stop your periods altogether. If you have any questions or concerns about your birth control method and how it may be affecting your periods, make an appointment with a doctor. 


Being overweight can disrupt your hormones and affect your menstrual cycle. It can also be a sign of conditions such as diabetes, thyroid disorders or polycystic ovarian syndrome (PCOS). If you are overweight (have a body mass index of 30 or above) and have late, missed or irregular periods make an appointment with a doctor. 

Being underweight 

Being underweight (a body mass index of 18.5 or below) or suddenly losing a lot of weight can cause your periods to stop. Not consuming enough calories can stop your body from producing the hormones needed for ovulation (when eggs are released from your ovaries). Eating disorders like anorexia or bulimia commonly cause your periods to stop. If you think you may be suffering from an eating disorder, that your eating may be affecting your periods, or if you think that you worry too much about controlling the food you eat, a GP can discuss this with you and may arrange for you to have specialist help. 


During perimenopause (the months or years leading up to menopause) levels of the hormone oestrogen decline causing irregular, late, or missed periods. 

Polycystic ovarian syndrome (PCOS)

PCOS is a hormonal disorder that causes symptoms such as obesity, facial hair, and acne. It is a common cause of irregular or absent periods. 

Underlying medical conditions 

Some chronic (long-term) medical conditions can cause your periods to stop or be late including: 

  • diabetes
  • heart disease
  • overactive thyroid
  • premature menopause (menopause before the age of 45) 
  • tumours of the pituitary gland (cancerous or non-cancerous) 
  • adrenal gland disorders
  • liver problems
  • ovarian cysts 
  • congenital (present at birth) disorders such as Turners syndrome and androgen insensitivity

How much delay is normal?

If you haven’t had a period for more than 6 weeks, it is considered a missed period, and we would recommend that you see a doctor

You should see a doctor immediately if you: 

  • have had a negative pregnancy test and have missed 3 periods in a row
  • are under 45 and have stopped having periods
  • are over 55 and still experience bleeding
  • are worried about irregular, late or absent periods 

How can I delay my periods?

There are times when having a period could cause significant distress. Many women will want to delay their periods if they are expecting to menstruate during an important event, such as a wedding or beach holiday. 

If you would like to delay your period for your holiday or wedding, a review with a doctor may help you.

If you are taking contraception, you may be advised to run two packs together, otherwise you may be prescribed medication that will delay your period. 

Don’t make any changes to any medication without discussing it with a doctor first.  

Get help from an online doctor

Get help from an online doctor

An online doctor can help to identify the cause of your missed or late period by asking you some questions about your normal cycle, general health, lifestyle and whether you have any other symptoms. 

They may ask about: 

  • your medical history
  • whether you are sexually active
  • your weight and any recent changes in your weight
  • how much exercise you take
  • whether you feel stressed 
  • any other symptoms you are experiencing

It’s easy to book an appointment with an NHS-trained GP at Medicspot. Simply click the link and select an appointment at a time and day that suits you. Appointments are often available the same day. 

Get help from a pharmacist

A pharmacist can help with late or missed periods by helping you to establish the cause. They can advise you on any medications you may be taking such as contraceptive pills, injections, or implants and recommend a reliable pregnancy test. They can also advise you on when to see a GP.

Find a pharmacy near you.


Missing a period can be a worrying time for many women. There are many reasons your period may be late including pregnancy, hormonal imbalances, lifestyle factors and medical conditions. A missed or late period usually isn’t anything to worry about but may be a sign of a medical condition that needs treatment. 

If your period is late, or you have missed a period and would like to talk to a doctor, make an appointment today. 


NHS: Stopped or missed period August 2nd 2019 (Accessed December 10th 2022) 

PubMed: Factors associated with the menstrual cycle irregularity and menopause February 2018 Accessed December 10th 2022) 

Penn Medicine: Why is my Period Late?  November 2nd 2020 Accessed December 10th 2022) 

Very Well Health: Why is My Period Late? 10 Reasons and What to Do November 9th 2022 Accessed December 10th 2022)