Osteoporosis has become one of the most widely recognized disorders of our times affecting an estimated 25 million women in this country. Recent evidence has suggested that premenstrual syndrome (PMS) is associated with a calcium deficiency state and bone loss. This may place premenopausal women at greater risk for osteoporosis. An entity such as PMS may be an important physiological marker of a calcium disturbance. The purpose of this investigation is to understand more completely the extent to which calcium balance is disturbed in severe PMS or Premenstrual Dysphoric Disorder (PMDD) by utilizing new tools to assess calcium and bone turnover. The long term objective is to elucidate the pathophysiology of PMDD or severe PMS as it relates to calcium hormones and bone markers. The experimental design involves the comparison between women witn severe PMS and asymptomatic controls.

Inclusion Criteria:

• Medical history of severe PMS for the PMS group
• No medical history of PMS for the control group
• Prospective 2 month documentation of moderate to severe symptoms for the PMS group
• Prospective 2 month documentation of absent symptoms for the control group
• General good health
• Regular menstrual cycles
• No history of metabolic bone disease

Exclusion Criteria:

• Amenorrhea
• Anorexia nervosa
• Malabsorption
• Inflammatory bowel disease
• Erosive gastrointestinal disease
• Gastrectomy
• Malignancy
• Multiple myeloma
• Primary hyperparathyroidism
• Use of suppressive doses of thyroxine
• Cushing's syndrome
• Use of glucocorticoids or anticonvulsants
• Use of diuretics
• Metabolic bone disease
• Pregnancy or perimenopause or menopause
• Mental retardation
• Menstrual irregularity
• Significant gynecologic abnormality
• Use of birth control pills