Premenopausal women who have recently undergone a study of their coronary (heart) arteries will have their blood hormone levels measured over one menstrual cycle. The investigators will correlate the blood hormone levels with coronary angiography results and with other markers of heart disease, such as a test that uses noninvasive, painless ultrasound waves to study the thickness of the arteries in the neck (carotid arteries). In addition blood cholesterol levels, blood sugar levels and other blood tests have been shown to correlate with heart disease will be measured.