Thyroid problems are common in women. Here is what you need to know. By Kari Bohlke, ScD
You may not give your thyroid a second thought if it’s functioning as it should, but this small gland plays a key role in many aspects health. Located at the front of the neck below the larynx, the thyroid produces hormones that affect metabolism, brain development, breathing, heart and nervous system functions, body temperature, muscle strength, skin dryness, menstrual cycles, weight, cholesterol levels, and more.1
Thyroid problems are common and tend to affect women more often than men. “The thyroid disorders that are most common are autoimmune conditions, which tend to be more prevalent in women,” explains Geanina Popoveniuc, MD, endocrinology fellow at Georgetown University Hospital/Washington Hospital Center. “That is probably because of the hormonal influences of both estrogen and progesterone.”
Thyroid disorders may cause the thyroid to produce too much thyroid hormone (hyperthyroidism) or too little thyroid hormone (hypothyroidism) or to develop benign or cancerous nodules. Fortunately, recognition and treatment of these problems can improve both health and quality of life.
When the thyroid produces too little thyroid hormone, the problem is called hypothyroidism. “The prevalence of this condition is relatively high in the general population—about 4.5 percent,” says Dr. Popoveniuc. “Moreover, in adults who are more than 65 years of age, the prevalence goes as high as 10 percent.”
Symptoms of hypothyroidism include fatigue, weight gain, puffy face, cold intolerance, joint and muscle pain, constipation, dry skin, dry and thinning hair, decreased sweating, heavy or irregular menstrual periods, impaired fertility, depression, and slowed heart rate.2
The most common cause of hypothyroidism is an autoimmune disease known Hashimoto’s thyroiditis. In people with Hashimoto’s, the immune system produces anti-thyroid antibodies that attack the thyroid and reduce hormone production. Hypothyroidism can also be caused by other types of thyroiditis, certain types of medications, and thyroid treatments that reduce or eliminate thyroid function (such as radioactive iodine treatment or surgery to remove all or part of the thyroid).
Treatment of hypothyroidism typically involves medication that contains synthetic thyroid hormone.
When the thyroid produces too much thyroid hormone, the problem is called hyperthyroidism. “It’s less frequent than hypothyroidism,” says Dr. Popoveniuc, “but it can reach a prevalence of about 1 percent in the general population.”
People with hyperthyroidism may notice a broad range of symptoms, such as nervousness or irritability, fatigue, heat intolerance, trouble sleeping, hand tremors, rapid or irregular heartbeat, frequent bowel movements, weight loss, and mood swings. Some people may also develop a goiter, which is a lump in the neck caused by enlargement of the thyroid.3
Once again an autoimmune disease bears much of the blame: the most common cause of hyperthyroidism is an autoimmune disease known as Graves’ disease. In people with Graves’ disease, the immune system produces an antibody known as thyroid-stimulating immunoglobulin. This antibody causes the thyroid to overproduce thyroid hormone. Problems such as thyroid nodules and thyroiditis (inflammation of the thyroid) can also cause temporary or longer-term hyperthyroidism. If thyroiditis is to blame, an initial period of hyperthyroidism often develops into hypothyroidism.
Depending on the underlying cause of the hyperthyroidism, treatment may involve anti-thyroid medications, radioactive iodine that destroys thyroid cells, or surgery to remove all or part of the thyroid. Treatments such as radioactive iodine and surgery often lead to hypothyroidism, but this can be treated with thyroid hormone medication.
During the first year after pregnancy, roughly 5 percent of women develop a condition known as postpartum thyroiditis.4 Like Hashimoto’s thyroiditis and Graves’ disease, postpartum thyroiditis is thought to be an autoimmune disease. The course of the condition can vary from woman to woman, but it often starts with a period of hyperthyroidism that is followed by a period of hypothyroidism. Normal thyroid function often returns by one year after delivery, but some women develop permanent hypothyroidism.5 Women may be more likely to develop postpartum thyroiditis if they have another autoimmune disease, a personal or family history of thyroid problems, or previously had postpartum thyroiditis.
The need for treatment depends on the type and the severity of the symptoms. Bothersome hypothyroidism can be treated with thyroid hormone, which may be necessary for only a few months.
In the simplest terms, thyroid nodules are lumps in the thyroid. Nodules are common (particularly in women) and may be discovered during a physical examination or during imaging for another condition.6 “Thyroid nodules are important particularly because they may harbor malignancy,” says Dr. Popoveniuc. “In general, a person who has been diagnosed with a thyroid nodule will have a risk of that nodule’s being malignant of about 5 percent.”
Evaluation of thyroid nodules may include a physical examination, blood tests to evaluate thyroid function, ultrasound of the thyroid, and a biopsy to collect a small sample of the nodule for further evaluation.
If testing reveals that the nodule or nodules are benign (non-cancerous), treatment may not be necessary. If benign nodules are large or have altered thyroid function, however, a doctor may recommend treatment with surgery or another approach.
Surgery may also be necessary if test results are indeterminate (unable to say for certain whether cancer is present).6 In this case, surgery to remove all or part of the thyroid allows for more-extensive evaluation of the thyroid. New tests, however, may reduce the number of surgeries that need to be performed for this reason (see sidebar “Tests Seek to Reduce Number of Thyroid Surgeries”).
In some cases, thyroid nodules are found to contain cancer. Each year in the United States, thyroid cancer is diagnosed in roughly 43,000 women and 13,000 men.7 There are several different types of thyroid cancer, and the most common types—papillary and follicular thyroid cancers—are often quite curable if diagnosed at an early stage.8 Treatment depends on the type and the stage of the cancer but may include surgery, thyroid hormone treatment, radioactive iodine therapy, external radiation therapy, chemotherapy, and/or targeted therapy. Targeted therapies are drugs that interfere with certain biologic pathways that contribute to cancer cell growth or survival.
If You Suspect a Problem
If you suspect that you have a thyroid problem, being evaluated by your primary care provider is a good place to start. If an initial evaluation identifies a thyroid abnormality, says Dr. Popoveniuc, “a referral to an endocrinologist may be the best approach to ensure a comprehensive evaluation of the thyroid gland.”
Although thyroid problems can affect anyone, people with a family history of one of these conditions should be particularly vigilant: “Thyroid disorders tend to run in families,” notes Dr. Popoveniuc, “so if family history is present, basic evaluation of thyroid function should be performed. If there is a family history of thyroid nodules or thyroid cancer, then thyroid ultrasound should be performed.”
People with other types of autoimmune conditions—such as type 1 diabetes or rheumatoid arthritis—are also at increased risk for thyroid disease and may wish to discuss this risk with their physician.
“Thyroid disorders are very common entities, however the signs and the symptoms are generally nonspecific,” concludes Dr. Popoveniuc. “Patients should seek medical attention if they suspect a thyroid problem or if they have a strong family history of thyroid dysfunction, thyroid nodules, or thyroid cancer. And it’s important to know that the evaluation and the treatment should be done early to avoid undesired and life-threatening complications from untreated conditions.” _
1. Thyroid Function Tests. National Endocrine and Metabolic Diseases Information Service, National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) website. Available at: http://www.endocrine.niddk.nih.gov/pubs/thyroidtests/index.aspx. Accessed January 2, 2013.
2. Hypothyroidism. National Endocrine and Metabolic Diseases Information Service, NIDDK website. Available at: http://www.endocrine.niddk.nih.gov/pubs/hypothyroidism/index.aspx. Accessed January 2, 2013.
3. Hyperthyroidism. National Endocrine and Metabolic Diseases Information Service, NIDDK website. Available at: http://www.endocrine.niddk.nih.gov/pubs/hyperthyroidism/index.aspx. Accessed January 2, 2013.
4. Stagnaro-Green A, Pearce E. Thyroid disorders in pregnancy. Nature Reviews Endocrinology. 2012;8:650-8.
5. Yazbeck CF, Sullivan SD. Thyroid disorders during pregnancy. Medical Clinics of North America. 2012;96:235-56.
6. Popoveniuc G, Jonklaas J. Thyroid nodules. Medical Clinics of North America. 2012;96:329-49.
7. Cancer Facts & Figures 2012. American Cancer Society website. Available at: http://www.cancer.org/research/cancerfactsfigures/cancerfactsfigures/cancer-facts-figures-2012. Accessed January 2, 2013.
8. What You Need to Know About™ Thyroid Cancer. National Cancer Institute website. Available at: http://www.cancer.gov/cancertopics/wyntk/thyroid/page1. Accessed January 2, 2013.
9. Pregnancy and Thyroid Disease. National Endocrine and Metabolic Diseases Information Services NIDDK website. Available at: http://www.endocrine.niddk.nih.gov/pubs/pregnancy/index.aspx. Accessed January 2, 2013.
10. Alexander EK, Kennedy GC, Baloch ZW, et al. Preoperative diagnosis of benign thyroid nodules with indeterminate cytology. New England Journal of Medicine. 2012;367:705-15.
Thyroid Disorders during Pregnancy
During pregnancy, healthy levels of thyroid hormone in the mother are important to the health of both the mother and the baby. Although certain types of thyroid tests and treatments should not be used during pregnancy, there are safe ways to diagnosis and manage thyroid disease. Treatment of hypothyroidism with thyroid hormone medication, for example, not only is safe during pregnancy but is also important for the well-being of the baby.9
Tests Seek to Reduce Number of Thyroid Surgeries
Although most thyroid nodules are benign (non-cancerous), thyroid nodules are often tested for cancer using a procedure known as a fine-needle aspiration (FNA) biopsy. Roughly 25 percent of the time, the biopsy produces an indeterminate result; this means that it’s uncertain whether cancer is present.6 Patients with an indeterminate result often undergo surgery to remove all or part of the thyroid for further evaluation.
In an effort to reduce the number of surgeries that are performed because of indeterminate biopsy results, researchers have developed tests that can be performed on the biopsy sample after an indeterminate result. The Afirma Thyroid FNA Analysis, for example, evaluates the activity of certain genes and classifies the sample as either benign or suspicious for cancer.10 Another test—miRInform—assesses several molecular characteristics that are suggestive of cancer. This type of testing may help physicians and patients decide how to manage an indeterminate thyroid nodule.