PMS; premenstrual tension; PMT; premenstrual dysphoric disorder (severe PMS)
Most women experience some symptoms in the days leading up to their monthly period (i.e. during the second half of the menstrual cycle). Each woman’s symptoms are different and can vary month to month. If these symptoms, which can manifest as physical, behavioural and psychological, recur and are severe enough to impact on the woman’s daily life they are defined as premenstrual syndrome. Symptoms usually disappear or significantly decrease by the end of menstruation. More severe PMS is known as premenstrual dysphoric disorder (PMDD).
The first day of the menstrual cycle is defined as the first day of a monthly period. Around mid-cycle – approximately day 14 if cycles are regular – ovulation occurs. The empty follicle that has nurtured the egg forms a corpus luteum, which produces high levels of progesterone and lower levels of oestradiol to prepare the womb for pregnancy if conception has occurred. If the egg is not fertilised then the corpus luteum begins to break down and the production of progesterone and oestradiol begins to fall. This starts about a week before the next period.
The exact cause of premenstrual syndrome is not known however hormonal changes are thought to trigger the symptoms. After ovulation, when the corpus luteum begins to break down, the decline in progesterone levels towards the end of the menstrual cycle affects various chemicals in the brain (such as serotonin). Women with premenstrual syndrome do not have abnormal levels of hormones but they appear to be more sensitive to the effects of progesterone and oestrogen.
The degree to which these processes affect a woman will be influenced by her psychological and social wellbeing at that particular time in her life.
Up to 150 symptoms have been identified as part of premenstrual syndrome. The most common physical symptoms include breast tenderness, feeling bloated, headaches, acne, abdominal pain and fatigue. The most commonly experienced psychological symptoms include mood swings, irritability, anxiety, depression, feeling tearful, upset/emotional and difficulty in concentrating.
It is difficult to estimate how many women are affected. Up to 80% of women are thought to experience premenstrual symptoms while premenstrual syndrome itself is believed to affect between 5% and 25% of women in the reproductive age group. An estimated 5% to 8% of women suffer from severe premenstrual syndrome also known as premenstrual dysphoric disorder.
Early research has suggested that there may be a genetic-predisposition to developing premenstrual syndrome; however, this has not been proven. More research is needed to clarify whether premenstrual syndrome runs in families.
Diagnosis of premenstrual syndrome is based on the symptoms experienced by the patient and the point during the menstrual cycle at which the symptoms are experienced. In order to make a diagnosis, women are encouraged to keep a diary of their symptoms over the course of at least two consecutive months.
Because the exact cause of premenstrual syndrome is not yet understood treatment is focused on providing relief from symptoms. Management of premenstrual syndrome follows a tiered approach and each treatment option may take up to three months to make a noticeable difference. Initial management involves encouraging a woman to lead a healthy lifestyle, in terms of a balanced diet, regular exercise and minimising stress, as well as avoiding salt, caffeine and alcohol.
There are a number of herbal and vitamin supplements that are suggested for treatment of premenstrual syndrome. Some small studies have suggested that a good intake of the B vitamins thiamine and riboflavin as well as calcium and vitamin D may reduce the risk of premenstrual syndrome. Chasteberry (Vitex agnus castus) supplements are also supported by small studies. Further research is required to clarify the benefits of all of these. A woman should consult her doctor or dietician to discuss a regime that would be appropriate for her.
Cognitive behavioural therapy (a specific type of talking therapy) has also been shown to be of benefit in the management of premenstrual syndrome.
Medical treatments fall into two main groups: hormonal treatments and selective serotonin receptor inhibitors (or SSRIs).
Hormonal treatments – premenstrual syndrome can be alleviated in a proportion of women by using hormonal contraceptives that suppress ovulation. There are a number of ways to do this. The woman may be given oestrogen patches with progestogen (progesterone) in the form of tablets or a steroid-impregnated intrauterine device, called Mirena. Sometimes the combined oral contraceptive pill may be used. If a woman’s symptoms are very severe, she may be referred to a gynaecologist and be given another hormone treatment called a gonadotrophin-releasing hormone analogue. Since the hormonal methods used to ameliorate symptoms of premenstrual syndrome are also contraceptive, they are not appropriate if the woman is planning a pregnancy.
Selective serotonin receptor inhibitors – these are a group of medications that are used to treat depression (by elevating levels of the neurotransmitter serotonin) and have also been found to be very effective in the treatment of premenstrual syndrome. Unlike in depression, it is possible to take the medication just when experiencing symptoms, i.e. just in the second half of the menstrual cycle. This group of antidepressants may be harmful in pregnancy, so women that are planning a pregnancy should seek advice on treatment options from their doctor.
Vitamin supplements and complementary therapies to relieve the symptoms of premenstrual syndrome can cause side-effects; for example, calcium supplements can cause indigestion.
With hormonal treatments, sometimes a woman can be sensitive to the hormone and experience side-effects such as nausea or breast tenderness.
Some women feel nauseated or drowsy when they first take selective serotonin receptor inhibitors but these side-effects usually settle. This medication can also affect libido (sexual drive).
Women should discuss any concerns about the treatment options or side-effects mentioned with their doctor.
The frequency and severity of premenstrual syndrome varies from woman to woman and in each individual woman from month to month.
The greatest prevalence appears to be among women aged 30 to 50 but women can also experience a worsening of their symptoms around the time of their menopause (attributed to the erratic fluctuations in hormone levels at this time). Also it is a common time for a woman to experience stress in her life, for example as children leave home and ageing parents become more dependent. Hormone replacement therapy (HRT) can be used to treat symptoms due to the menopause and has a variable effect on symptoms experienced as part of premenstrual syndrome, which can occur during the perimenopausal period.
Premenstrual syndrome should resolve when the woman has passed her menopause as the woman no longer has a menstrual cycle with the associated cyclic release of steroid hormones from the ovary. Likewise, during pregnancy there will be no cyclical symptoms. However, women may experience similar symptoms such as abdominal bloating, breast tenderness and mood swings during pregnancy as levels of progesterone are high.
Last reviewed: Apr 2019