While PMS is linked to the luteal phase, the causes of PMS are not clear, but several factors may be involved. Changes in hormones during the menstrual cycle seem to be an important factor; changing hormone levels affect some women more than others. Chemical changes in the brain, stress, and emotional problems, such as depression, do not seem to cause PMS but they may make it worse. Low levels of vitamins and minerals, high sodium, alcohol, and/or caffeine can exacerbate symptoms such as water retention and bloating. PMS occurs more often in women who are between their late 20s and early 40s; have at least 1 child; have a family history of depression; and have a past medical history of either postpartum depression or a mood disorder.
There are no laboratory tests or unique physical findings to verify the diagnosis of PMS. The three key features[3] are:
The woman's chief complaint is one or more of the emotional symptoms associated with PMS (most typically irritability, tension, or unhappiness). The woman does not have PMS if she only has physical symptoms, such as cramps or bloating.&Symptoms appear predictably during the luteal (premenstrual) phase, reduce or disappear predictably shortly before or during menstruation, and remain absent during the follicular (preovulatory) phase.&The symptoms must be severe enough to interfere with the woman's everyday life
Mild PMS is common, and more severe symptoms would qualify as PMDD. PMS is not listed in the DSM-IV, unlike PMDD. To establish a pattern and determine if it is PMDD, a woman's physician may ask her to keep a prospective record of her symptoms on a calendar for at least two menstrual cycles.[6] This will help to establish if the symptoms are, indeed, limited to the premenstrual time, predictably recurring, and disruptive to normal functioning. A number of standardized instruments have been developed to describe PMS, including the Calendar of Premenstrual syndrome Experiences (COPE), the Prospective Record of the Impact and Severity of Menstruation (PRISM), and the Visual Analogue Scales (VAS).[3]
Other conditions that may better explain symptoms must be excluded.[3] A number of medical conditions are subject to exacerbation at menstruation, a process called menstrual magnification. These conditions may lead the woman to believe that she has PMS, when the underlying disorder may be some other problem, such as anemia, hypothyroidism, eating disorders and substance abuse.[3] A key feature is that these conditions may also be present outside of the luteal phase. Conditions that can be magnified perimenstrually include depression or other affective disorders, migraine, seizure disorders, fatigue, irritable bowel syndrome, asthma, and allergies.[3] Problems with other aspects of the female reproductive system must be excluded, including dysmenorrhea (pain during the menstrual period, rather than before it), endometriosis, perimenopause, and adverse effects produced by oral contraceptive pills.[3]
The National Institute of Mental Health research definition compares the intensity of symptoms from cycle days 5 to 10 to the six-day interval before the onset of the menstrual period.[3] To qualify as PMS, symptom intensity must increase at least 30% in the six days before menstruation. Additionally, this pattern must be documented for at least two consecutive cycles.
More than 200 different symptoms have been associated with PMS. Common emotional and non-specific symptoms include stress, anxiety, difficulty with sleep, headache, feeling tired, mood swings, increased emotional sensitivity, and changes in interest in sex.[4]
Physical symptoms associated with the menstrual cycle include bloating, lower back pain, abdominal cramps, constipation/diarrhea, swelling or tenderness in the breasts, cyclic acne, and joint or muscle pain, and food cravings.[5] The exact symptoms and their intensity vary significantly from woman to woman, and even somewhat from cycle to cycle and over time.[2] Most women with premenstrual syndrome experience only a few of the possible symptoms, in a relatively predictable pattern.[6]