Estrogen is one of the female hormones that helps regulate a woman’s passage through menstruation, and menopause.

Scientists are still learning about the actions of estrogen in the body. Studies have shown that estrogen affects almost every tissue or organ system, including the heart and blood vessels. Estrogen’s known effects on the cardiovascular system include a mix of positive and negative:

• Increases HDL cholesterol (the good kind)
• Decreases LDL cholesterol (the bad kind)
• Promotes blood clot formation, and also causes some changes that have the opposite effect
• Relaxes, smooths and dilates blood vessels so blood flow increases
• Soaks up free radicals, naturally occurring particles in the blood that can damage the arteries and other tissues.

Estrogen probably affects the cardiovascular system in other ways that are as yet undiscovered. New research continues to give scientists and physicians more information – and raise more questions about this important and controversial hormone.