Tracing the Thyroid's Role in Breast Health

Those who suffer from some form of thyroid disease or disorder are already well aware of the fact that this small butterfly-shaped gland in the throat can exert an astonishingly broad impact on one's overall health and well-being. In recent years, researchers have made a number of surprising discoveries linking the thyroid's status to the ability of other organs and body parts to function properly.

One unlikely connection is the recently discovered link between the thyroid gland and the development and health of breast tissue in females. According to researchers who have worked to uncover the role of the thyroid gland in breast health and development, these two seemingly unrelated parts of the body are actually closely intertwined.

As we enter the middle of Breast Cancer Awareness month, strategies for maintaining optimal breast health are at the forefront of many women's minds. This week, we'll consider the ways in which thyroid health and breast health are interrelated.

The Thyroid Gland and Breast Development

As part of the body's endocrine system, which regulates and distributes hormones, the thyroid plays a major role in the processes of growth and development that mark the passage from childhood to adolescence, and finally, to adulthood. In women, a major hallmark of this transition is the development of breast tissue. Researchers have recently highlighted a number of key ways in which the thyroid helps to control breast development in recent studies.

At the current time, it is believed that the most significant of these links is the production and distribution of the hormone prolactin, which spurs the development of breast tissue. The hormones released by the thyroid gland interact with prolactin in a unique way. In girls whose thyroid gland does not function properly, normal breast development is often impeded. In fully-developed women of childbearing age, prolactin fluctuations caused by thyroid disorders can cause other problems, such as breastfeeding difficulties.

The Thyroid-Breast Cancer Link

Over the course of the last several decades, conflicting reports of a possible connection between the thyroid gland and breast cancer have emerged from the scientific community. At one point, it was widely believed that some forms of thyroid disease treatment may put women at higher risk of developing breast cancer. Thyroid hormone replacement therapy and radioactive iodine therapy were both once implicated as possible culprits for heightened breast cancer risk.

However, more recent research has seemed to invalidate this hypothesized link. Several large randomized studies of women's health data found no compelling statistical link between common thyroid disorders such as hypothyroidism and hyperthyroidism and breast cancer. On the other hand, what recent studies have uncovered is a heretofore unknown connection between thyroid cancer and breast cancer. Some researchers have conjectured that some unknown hormonal connection may be the missing link that explains this risk association. Women with family histories of either thyroid cancer or breast cancer are urged to be especially vigilant for signs and symptoms of both diseases, and to frequently perform breast exams to help aid in early detection of breast cancer.

Thyroid Health and Breastfeeding

Breastfeeding has become an increasingly popular choice for many women in recent years, as the unparalleled health benefits of breast milk have begun to be more widely emphasized by the public health community. However, for some women with histories of thyroid disorders and diseases, this natural process can be fraught with difficulties and frustrations.

Because of the sensitivity and delicacy of the interaction between thyroid hormones and the hormonal compound prolactin, even a slight thyroid imbalance can interfere with the normal development and maintenance of new mother's breast milk supply.

The hormone fluctuations of pregnancy and childbirth can often exacerbate mild, even previously undiagnosed cases of hypothyroidism. Some women who have never experienced thyroid disease before pregnancy may find their efforts at breastfeeding thwarted by deficiencies in the thyroid hormone supply.

In addition, because of the harsh nature of several common treatments for thyroid disease, it is important to consult with your doctor whether these agents could be passed on to a nursing infant via the breast milk. Women who are undergoing radioactive iodine treatment, for example, cannot breastfeed safely. On the other hand, thyroid hormone replacement therapy is often safe for breastfeeding mothers, although it should be closely monitored by a physician.

If you're concerned about the connection between your thyroid and breast health, talk to a doctor to get a more personalized assessment of this link and of the treatments that will work with your unique health history. With a bit of planning and extra vigilance, most women with thyroid disease can achieve and maintain optimal breast health throughout their life span.

For Further Reading

• http://cpmcnet.columbia.edu/dept/thyroid/women.html

• http://www.thyroid.ca/Guides/HG08.html#Breast