Premenstrual syndrome (PMS) is the name given to the physical, psychological and behavioural symptoms that can occur in the two weeks before a woman's monthly period. It is also known as premenstrual tension (PMT).
There are many different symptoms of PMS, but typical examples are bloating, breast pain, mood swings, feeling irritable and loss of interest in sex.
These symptoms usually improve when your period starts and disappear a few days afterwards.
Nearly all women of childbearing age have some premenstrual symptoms, but women in their late 20s to their early 40s are most likely to experience PMS.
Around 1 in every 20 women have symptoms that are severe enough to stop them living their normal lives. This is often the result of a more intense type of PMS known as premenstrual dysphoric disorder (PMDD).
When to see your GP
You should see your GP if you are finding it difficult to deal with the symptoms of PMS. They can help determine if you have PMDD and may be able to offer you advice and treatment to manage the symptoms you're experiencing.
Why it happens
The exact cause of PMS is not fully understood. However, it is thought to be linked to the changing levels of hormones in the body during a woman's menstrual cycle.
The fact that PMS improves during pregnancy and after the menopause, when hormone levels are stable, supports this theory.
Certain lifestyle factors, such as lack of exercise, stress and a poor diet, are also thought to aggravate the symptoms of PMS.
Managing PMS symptoms
There is no cure for PMS, but if your symptoms are not severe, certain lifestyle changes can help you manage them. These include:
a healthy diet
regular exercise to improve your health and fitness
learning techniques to help relieve stress
Psychological therapy or hormone medications may be recommended in more severe cases.
Symptoms of premenstrual syndrome (PMS)
There are many different symptoms of premenstrual syndrome (PMS), which can vary from person to person and change slightly every month.
For example, you may find that you have similar PMS symptoms every month, but they vary in intensity, or you may have slightly different symptoms every few months. PMS tends to be different for every woman.
The symptoms of PMS usually happen at the same time in your menstrual cycle each month, which can be up to two weeks before your period starts. They usually improve once your period has started and disappear until your cycle starts again.
Common symptoms of PMS
More than 100 different symptoms of PMS have been recorded. Some of the most common are listed below.
pain and discomfort in your abdomen (tummy)
muscle and joint pain
trouble sleeping (insomnia)
weight gain (up to 1kg)
Any chronic (long-term) illnesses, such as asthma or migraines, may get worse.
Psychological and behavioural symptoms
feeling upset or emotional
feeling irritable or angry
confusion and forgetfulness
loss of libido (loss of interest in sex)
appetite changes or food cravings
Premenstrual dysphoric disorder
While most women with PMS find their symptoms uncomfortable, a small percentage have symptoms that are severe enough to stop them living their normal lives. This is the result of a more intense type of PMS known as premenstrual dysphoric disorder (PMDD).
The symptoms of PMDD are similar to those of PMS, but are more exaggerated and often have more psychological symptoms than physical ones. Symptoms can include:
feelings of hopelessness
persistent sadness or depression
extreme anger and anxiety
decreased interest in usual activities
sleeping much more or less than usual
very low self-esteem
extreme tension and irritability
As depression is a common symptom of PMDD, it is possible that a woman with PMDD may have thoughts about suicide.
PMDD can be particularly difficult to deal with as it can have a negative effect on your daily life and relationships.
When to see your GP
It's normal to experience mild PMS symptoms in the two weeks before your period starts. However, you should see your GP if the symptoms are making everyday life difficult.
Your GP may ask you to use a diary to record how you're feeling each day in the run-up to your period. You may have to do this for at least two or three months so your GP can spot any patterns in your symptoms.
PMDD is only diagnosed when your mood symptoms seriously affect your relationships and stop you from functioning properly at work or school. Your GP may refer you to a mental health specialist for further assessment and treatment if they think you have PMDD.
Causes of premenstrual syndrome (PMS)
The exact cause of premenstrual syndrome (PMS) is not fully understood, but there are a number of things that may contribute to the symptoms.
During your menstrual cycle, levels of hormones such as oestrogen and progesterone rise and fall. Hormone changes are thought to be the biggest contributing factor to many of the symptoms of PMS.
The fact that PMS improves during pregnancy and after themenopause, when hormone levels are stable, supports this theory.
Chemical changes in the brain
It has also been suggested that the changes in hormone levels during the menstrual cycle may affect the levels of certain chemicals in your brain, such as serotonin.
Serotonin is known to help regulate your mood and make you feel happier, so a reduction in the level of serotonin caused by changes in hormone levels may explain the mood changes often associated with PMS.
It may also explain why a type of antidepressant medication that increases serotonin levels (known as selective serotonin reuptake inhibitors, or SSRIs) helps some women with PMS.
There are also a number of lifestyle factors that can increase your risk of PMS. These are outlined below.
Weight and exercise
Research has shown that you are more likely to have PMS if you are obese (with a body mass index of more than 30) and if you do little exercise.
You may find that your symptoms of PMS get worse as you become more stressed. While it is not a direct cause, stress can aggravate the symptoms of PMS.
Eating too much of some foods and too little of others may also contribute to PMS symptoms. For example, too much salty food may make you feel bloated.
Alcohol and caffeinated drinks can disrupt your mood and energy levels.
Low levels of vitamins and minerals may also make your PMS symptoms worse.
Treating premenstrual syndrome (PMS)
There is no cure for premenstrual syndrome (PMS), but there are treatments that can help you manage your symptoms so they do not interfere with your daily life.
If your PMS is mild or moderate, you may want to make changes to your diet and lifestyle before resorting to medical treatment. This is because many of the medical treatments can have side effects that may be worse than your PMS symptoms.
The following tips can help you maintain a healthy balanced daily diet, and may help control the symptoms of PMS:
eat smaller meals more frequently to help reduce bloating
avoid eating salty foods to limit bloating and fluid retention
drink plenty of water to avoid dehydration – being dehydrated can make headaches and tiredness worse
eat lots of complex carbohydrates, which can be found in foods such as fruit, vegetables and wholegrains
eat calcium-rich foods such as cheese and milk to improve the physical and psychological symptoms of PMS – if you can't eat dairy products, try calcium-fortified soya alternatives
eat plenty of fruit and vegetables, which are rich in vitamins and minerals and may ease your PMS symptoms – aim to eat at least five portions a day
avoid caffeine and alcohol, which can affect your mood and energy levels
If possible, aim to do at least 150 minutes (2 hours and 30 minutes) of moderate-intensity aerobic activity every week. Examples of activities include walking, swimming and cycling.
Exercise improves your overall health and can help alleviatedepression and tiredness.
Stretching and breathing exercises, such as yoga and pilates, can help you sleep better and reduce your stress levels.
There are many non-prescribed alternative treatments and supplements that claim to help treat PMS that some women may find helpful in easing their symptoms.
For example, supplements of calcium, vitamin D, magnesium and agnus castus (a herb known as chasteberry) may reduce some symptoms of PMS.
However, many complementary therapies and supplements have either not been tested or have not been proven to be effective.
Always see your GP before taking any supplements, as taking them alongside certain medications or in excessive amounts can be harmful.
If you decide to take a complementary treatment, take one at a time so you know it works for you. Go back to your GP if your symptoms don't change after three months, as another treatment may be recommended.
If you have psychological symptoms, such as feeling depressed or emotional, it may help to talk to a health professional.
Cognitive behavioural therapy (CBT) is the term for a group of therapies designed to help solve problems such as anxiety and depression. A cognitive behavioural therapist can help you learn new ways of managing some of your symptoms.
You may wish to try a medical treatment if your PMS is severe or you have premenstrual dysphoric disorder (PMDD). However, there is no single treatment that works for everyone.
A wide range of treatments is available. You may have to try several before you find one that suits you. Your choice of treatment will be based on your symptoms and how severe they are, and the possible side effects of the medication.
If you are prescribed treatment for PMS, you may be asked to record any changes to your symptoms so that you know how effective it is for you. If the treatment doesn't ease your symptoms, you may be prescribed an alternative.
Medical treatments for PMS include:
a combined oral contraceptive pill
oestrogen-only patches and implants
selective serotonin reuptake inhibitors (SSRIs)
gonadotrophin-releasing hormone (GnRH) analogues
These are described in more detail below.
Painkilling medication, including paracetamol and non-steroidal anti-inflammatory drugs (NSAIDs), can relieve some of the painful PMS symptoms such as stomach cramps, headaches, muscle pain and joint pain.
These medications are available over the counter without a prescription, so you should make sure you read the manufacturer's instructions before taking them to make sure they are suitable. For example, children under the age of 16 shouldn't take aspirin and people with asthma should not take ibuprofen.
Oral contraceptive pills
As well as preventing pregnancy, the combined contraceptive pill may help improve symptoms of PMS in some women by preventing ovulation (when an egg is released from your ovaries).
In particular, newer types of contraceptive pill containing certain versions of the hormone progestogen, such as the Yasmin pill, have been shown to be effective in treating some PMS symptoms, and may even be effective in improving symptoms of PMDD.
However, contraceptive pills do not help all women and they can have side effects similar to the symptoms of PMS, such as breast pain or a depressed mood.
Oestrogen-only patches and implants
Like combined contraceptive pills, oestrogen-only patches and implants may help improve some symptoms of PMS by preventing ovulation. However, they are usually only used to treat PMS under the guidance of a gynaecologist.
Unless you have had a hysterectomy (removal of your womb), oestrogen patches and implants also need to be combined with a low dose of the hormone progestogen to reduce the risk of thickening of the womb lining (endometrial hyperplasia), which can develop intowomb cancer. This may be in the form of progestogen tablets or a progestogen-releasing intrauterine system (IUS).
Side effects of using an oestrogen patch can include skin irritation, itching and soreness, and the additional progestogen dose can have side effects similar to the symptoms of PMS.
Selective serotonin reuptake inhibitors (SSRIs)
Selective serotonin reuptake inhibitors (SSRIs) may be the most effective treatment if you have severe PMS or PMDD.
SSRIs, such as fluoxetine and sertraline, are antidepressants that can be taken daily to relieve tiredness, food cravings and sleep problems, and combat depression.
However, SSRIs also may have negative side effects that could outweigh their benefits, such as nausea, insomnia, headache and loss of libido (less interest in sex).
Gonadotrophin-releasing hormone (GnRH) analogues
Gonadotrophin-releasing hormone (GnRH) analogues are synthetic hormones that create a temporary menopause, and stop your periods by blocking the production of oestrogen and progesterone. They are taken as an injection.
GnRH analogues should only be used in women with severe PMS when all other treatments have failed. They often have side effects such as hot flushes, vaginal dryness, loss of libido and osteoporosis(thinning of the bones).
They should only be taken alone for up to six months. If GnRH analogues are used for longer than this, you will be advised to take hormone replacement therapy (HRT) to reduce menopausal complications such as osteoporosis.