Premenstrual Syndrome - Symptoms

Causes

It is not clear what causes of premenstrual syndrome. Fluctuations in gonadal hormones (progesterone or estrogen) and brain chemicals may play a role although their exact significance is unclear. Hormonal levels seem to be the same in women whether or not they have premenstrual syndrome. It is possible that women with premenstrual syndrome are somehow more sensitive to these changing levels of hormones.

The Hypothalamic-Pituitary-Adrenal (HPA) System

The hypothalamic-pituitary-adrenal (HPA) system controls reproduction, appetite, and feelings of well-being. The HPA is also involved in regulating the stress response. A number of reproductive hormones and neurotransmitters (chemical messengers in the brain) play important and complicated interrelated roles in the activity of the HPA system. Disruptions in these chemicals may be important in PMS and premenstrual dysphoric disorder (PMDD).

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• Reproductive hormones. The two important female hormones, progesterone and estrogen, are at their highest levels during the premenstrual period. An abnormal response to progesterone, more so than estrogen, may be the primary factor in PMS.
• Neurotransmitters. Each hormone is involved in the regulation of two neurotransmitters, serotonin and gamma-aminobutyric acid (GABA). These brain chemicals have properties that appear to protect against PMS symptoms. Serontonin helps regulate mood and behavior. GABA has an effect on calmness and anxiety.
• Stress hormones. Stress hormones include cortisol and norepinephrine.

The exact roles and relationships of any of these substances in PMS or premenstrual dysphoric disorder (PMDD) are still unclear. Evidence increasingly suggests that cyclic fluctuations in some of these hormones -- not whether they are high or low -- may be the important factors in premenstrual problems.

Review Date: 07/26/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org).