Premenstrual Syndrome - Causes

Stress Hormones. After a stressful event, the HPA system releases certain neurotransmitters called catecholamines, importantly dopamine and epinephrine (adrenaline).

These chemicals trigger the release of the steroid hormones known as glucocorticoids, which in turn produce cortisol, the primary stress hormone.
Cortisol activates systems throughout the body to respond to this stressful event (the fight or flight response). Low levels are associated with depression.

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One study observed that women with PMS-related depression had lower cortisol levels during the premenstrual phase and higher levels during menstruation compared to women with few PMS symptoms.

Calcium and Magnesium Imbalances

Calcium and magnesium help nerve cells to communicate and blood vessels to widen and narrow. Female hormones, including estrogen, regulate calcium and magnesium. Hormonal swings during the premenstrual phase, then, also cause variations in these important minerals. Some researchers believe that imbalances in these minerals may contribute to PMS. (Vitamin D, which is essential for calcium absorption, may also be deficient in women with PMS.)

One study observed very low levels of magnesium and high levels of calcium during the premenstrual phase. Some experts hypothesize then that deficiencies in magnesium may be responsible for triggering symptoms. The effects are likely to be more complicated than this, however, since taking calcium supplements appears to reduce PMS symptoms in some women, while taking magnesium seems to have no effect.

Other Physical Factors

Peptides. Some researchers are studying certain peptides that vary during the menstrual cycle among women with and without PMS. These substances include arginine vasopressin (AVP), which affects water retention, and atrial natriuretic peptide (ANP), which increases sodium elimination.

Thyroid Hormone. A few studies report that some women with PMS may be more sensitive than others to variations in thyroid hormone, which can impact both physical and emotional well-being.

Prolactin. Some PMS symptoms, particularly breast pain, may be caused by excess levels of prolactin, a hormone produced by the pituitary gland that stimulates the glands in the breasts.

Endometrial Abnormalities. Results of a study of women who had both PMS and heavy bleeding (menorrhagia) suggested that substances in the endometrium (the lining of the uterus) might cause PMS symptoms.